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[ Upstream commit b2aa3b4d64e460ac606f386c24e7d8a873ce6f1a ]
There currently isn't a max limit an event probe can be. One could make an
event greater than PAGE_SIZE, which makes the event useless because if
it's bigger than the max event that can be recorded into the ring buffer,
then it will never be recorded.
A event probe should never need to be greater than 3K, so make that the
max size. As long as the max is less than the max that can be recorded
onto the ring buffer, it should be fine.
Cc: stable@vger.kernel.org
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Fixes: 93ccae7a22274 ("tracing/kprobes: Support basic types on dynamic events")
Link: https://patch.msgid.link/20260428122302.706610ba@gandalf.local.home
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
[ adjusted context to place MAX_PROBE_EVENT_SIZE near MAX_STRING_SIZE and appended EVENT_TOO_BIG after NEED_STRING_TYPE ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit fad217e16fded7f3c09f8637b0f6a224d58b5f2e ]
When a tracepoint goes through the 0 -> 1 transition, tracepoint_add_func()
invokes the subsystem's ext->regfunc() before attempting to install the
new probe via func_add(). If func_add() then fails (for example, when
allocate_probes() cannot allocate a new probe array under memory pressure
and returns -ENOMEM), the function returns the error without calling the
matching ext->unregfunc(), leaving the side effects of regfunc() behind
with no installed probe to justify them.
For syscall tracepoints this is particularly unpleasant: syscall_regfunc()
bumps sys_tracepoint_refcount and sets SYSCALL_TRACEPOINT on every task.
After a leaked failure, the refcount is stuck at a non-zero value with no
consumer, and every task continues paying the syscall trace entry/exit
overhead until reboot. Other subsystems providing regfunc()/unregfunc()
pairs exhibit similarly scoped persistent state.
Mirror the existing 1 -> 0 cleanup and call ext->unregfunc() in the
func_add() error path, gated on the same condition used there so the
unwind is symmetric with the registration.
Fixes: 8cf868affdc4 ("tracing: Have the reg function allow to fail")
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20260413190601.21993-1-devnexen@gmail.com
Signed-off-by: David Carlier <devnexen@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
[ changed `tp->ext->unregfunc` to `tp->unregfunc` to match older struct layout ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit c6e80201e057dfb7253385e60bf541121bf5dc33 ]
to_ratio() computes BW_SHIFT-scaled bandwidth ratios from u64 period and
runtime values, but it returns unsigned long. tg_rt_schedulable() also
stores the current group limit and the accumulated child sum in unsigned
long.
On 32-bit builds, large bandwidth ratios can be truncated and the RT
group sum can wrap when enough siblings are present. That can let an
overcommitted RT hierarchy pass the schedulability check, and it also
narrows the helper result for other callers.
Return u64 from to_ratio() and use u64 for the RT group totals so
bandwidth ratios are preserved and compared at full width on both 32-bit
and 64-bit builds.
Fixes: b40b2e8eb521 ("sched: rt: multi level group constraints")
Assisted-by: Codex:GPT-5
Signed-off-by: Joseph Salisbury <joseph.salisbury@oracle.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260403210014.2713404-1-joseph.salisbury@oracle.com
[ dropped `extern` keyword from `to_ratio()` declaration ]
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit b8e753128ed074fcb48e9ceded940752f6b1c19f upstream.
Currently, the coredump_task_exit() function sets the task state
to TASK_UNINTERRUPTIBLE|TASK_FREEZABLE, which usually works well.
But a combination of large memory and slow (and/or highly contended)
mass storage can cause application core dumps to take more than
two minutes, which can cause check_hung_task(), which is invoked by
check_hung_uninterruptible_tasks(), to produce task-blocked splats.
There does not seem to be any reasonable benefit to getting these splats.
Furthermore, as Oleg Nesterov points out, TASK_UNINTERRUPTIBLE could
be misleading because the task sleeping in coredump_task_exit() really
is killable, albeit indirectly. See the check of signal->core_state
in prepare_signal() and the check of fatal_signal_pending()
in dump_interrupted(), which bypass the normal unkillability of
TASK_UNINTERRUPTIBLE, resulting in coredump_finish() invoking
wake_up_process() on any threads sleeping in coredump_task_exit().
Therefore, change that TASK_UNINTERRUPTIBLE to TASK_IDLE.
Reported-by: Anhad Jai Singh <ffledgling@meta.com>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Acked-by: Oleg Nesterov <oleg@redhat.com>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Chris Mason <clm@fb.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit c1fa0bb633e4a6b11e83ffc57fa5abe8ebb87891 upstream.
When an already-exiting task oopses, make_task_dead() currently calls
do_task_dead() with preemption enabled. That is forbidden:
do_task_dead() calls __schedule(), which has a comment saying "WARNING:
must be called with preemption disabled!".
If an oopsing task is preempted in do_task_dead(), between becoming
TASK_DEAD and entering the scheduler explicitly, bad things happen:
finish_task_switch() assumes that once the scheduler has switched away
from a TASK_DEAD task, the task can never run again and its stack is no
longer needed; but that assumption apparently doesn't hold if the dead
task was preempted (the SM_PREEMPT case).
This means that the scheduler ends up repeatedly dropping references on
the dead task's stack, which can lead to use-after-free or double-free
of the entire task stack; in other words, two tasks can end up running
on the same stack, resulting in various kinds of memory corruption.
(This does not just affect "recursively oopsing" tasks; it is enough to
oops once during task exit, for example in a file_operations::release
handler)
Fixes: 7f80a2fd7db9 ("exit: Stop poorly open coding do_task_dead in make_task_dead")
Cc: stable@kernel.org
Signed-off-by: Jann Horn <jannh@google.com>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 69772f509e084ec6bca12dbcdeeeff41b0103774 ]
Inside mark_stack_slot_misc, we should not upgrade STACK_INVALID to
STACK_MISC when allow_ptr_leaks is false, since invalid contents
shouldn't be read unless the program has the relevant capabilities.
The relaxation only makes sense when env->allow_ptr_leaks is true.
However, such conversion in privileged mode becomes unnecessary, as
invalid slots can be read without being upgraded to STACK_MISC.
Currently, the condition is inverted (i.e. checking for true instead of
false), simply remove it to restore correct behavior.
Fixes: eaf18febd6eb ("bpf: preserve STACK_ZERO slots on partial reg spills")
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Reported-by: Tao Lyu <tao.lyu@epfl.ch>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20241204044757.1483141-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 482d548d40b0af9af730e4869903d4433e44f014 ]
When verifier validates BPF_ST_MEM instruction that stores known
constant to stack (e.g., *(u64 *)(r10 - 8) = 123), it effectively spills
a fake register with a constant (but initially imprecise) value to
a stack slot. Because read-side logic treats it as a proper register
fill from stack slot, we need to mark such stack slot initialization as
INSN_F_STACK_ACCESS instruction to stop precision backtracking from
missing it.
Fixes: 41f6f64e6999 ("bpf: support non-r10 register spill/fill to/from stack in precision tracking")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/r/20231209010958.66758-1-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 18a433b62061e3d787bfc3e670fa711fecbd7cb4 ]
Now that precision backtracing is supporting register spill/fill to/from
stack, there is another oportunity to be exploited here: minimizing
precise STACK_ZERO cases. With a simple code change we can rely on
initially imprecise register spill tracking for cases when register
spilled to stack was a known zero.
This is a very common case for initializing on the stack variables,
including rather large structures. Often times zero has no special
meaning for the subsequent BPF program logic and is often overwritten
with non-zero values soon afterwards. But due to STACK_ZERO vs
STACK_MISC tracking, such initial zero initialization actually causes
duplication of verifier states as STACK_ZERO is clearly different than
STACK_MISC or spilled SCALAR_VALUE register.
The effect of this (now) trivial change is huge, as can be seen below.
These are differences between BPF selftests, Cilium, and Meta-internal
BPF object files relative to previous patch in this series. You can see
improvements ranging from single-digit percentage improvement for
instructions and states, all the way to 50-60% reduction for some of
Meta-internal host agent programs, and even some Cilium programs.
For Meta-internal ones I left only the differences for largest BPF
object files by states/instructions, as there were too many differences
in the overall output. All the differences were improvements, reducting
number of states and thus instructions validated.
Note, Meta-internal BPF object file names are not printed below.
Many copies of balancer_ingress are actually many different
configurations of Katran, so they are different BPF programs, which
explains state reduction going from -16% all the way to 31%, depending
on BPF program logic complexity.
I also tooked a closer look at a few small-ish BPF programs to validate
the behavior. Let's take bpf_iter_netrlink.bpf.o (first row below).
While it's just 8 vs 5 states, verifier log is still pretty long to
include it here. But the reduction in states is due to the following
piece of C code:
unsigned long ino;
...
sk = s->sk_socket;
if (!sk) {
ino = 0;
} else {
inode = SOCK_INODE(sk);
bpf_probe_read_kernel(&ino, sizeof(ino), &inode->i_ino);
}
BPF_SEQ_PRINTF(seq, "%-8u %-8lu\n", s->sk_drops.counter, ino);
return 0;
You can see that in some situations `ino` is zero-initialized, while in
others it's unknown value filled out by bpf_probe_read_kernel(). Before
this change code after if/else branches have to be validated twice. Once
with (precise) ino == 0, due to eager STACK_ZERO logic, and then again
for when ino is just STACK_MISC. But BPF_SEQ_PRINTF() doesn't care about
precise value of ino, so with the change in this patch verifier is able
to prune states from after one of the branches, reducing number of total
states (and instructions) required for successful validation.
Similar principle applies to bigger real-world applications, just at
a much larger scale.
SELFTESTS
=========
File Program Insns (A) Insns (B) Insns (DIFF) States (A) States (B) States (DIFF)
--------------------------------------- ----------------------- --------- --------- --------------- ---------- ---------- -------------
bpf_iter_netlink.bpf.linked3.o dump_netlink 148 104 -44 (-29.73%) 8 5 -3 (-37.50%)
bpf_iter_unix.bpf.linked3.o dump_unix 8474 8404 -70 (-0.83%) 151 147 -4 (-2.65%)
bpf_loop.bpf.linked3.o stack_check 560 324 -236 (-42.14%) 42 24 -18 (-42.86%)
local_storage_bench.bpf.linked3.o get_local 120 77 -43 (-35.83%) 9 6 -3 (-33.33%)
loop6.bpf.linked3.o trace_virtqueue_add_sgs 10167 9868 -299 (-2.94%) 226 206 -20 (-8.85%)
pyperf600_bpf_loop.bpf.linked3.o on_event 4872 3423 -1449 (-29.74%) 322 229 -93 (-28.88%)
strobemeta.bpf.linked3.o on_event 180697 176036 -4661 (-2.58%) 4780 4734 -46 (-0.96%)
test_cls_redirect.bpf.linked3.o cls_redirect 65594 65401 -193 (-0.29%) 4230 4212 -18 (-0.43%)
test_global_func_args.bpf.linked3.o test_cls 145 136 -9 (-6.21%) 10 9 -1 (-10.00%)
test_l4lb.bpf.linked3.o balancer_ingress 4760 2612 -2148 (-45.13%) 113 102 -11 (-9.73%)
test_l4lb_noinline.bpf.linked3.o balancer_ingress 4845 4877 +32 (+0.66%) 219 221 +2 (+0.91%)
test_l4lb_noinline_dynptr.bpf.linked3.o balancer_ingress 2072 2087 +15 (+0.72%) 97 98 +1 (+1.03%)
test_seg6_loop.bpf.linked3.o __add_egr_x 12440 9975 -2465 (-19.82%) 364 353 -11 (-3.02%)
test_tcp_hdr_options.bpf.linked3.o estab 2558 2572 +14 (+0.55%) 179 180 +1 (+0.56%)
test_xdp_dynptr.bpf.linked3.o _xdp_tx_iptunnel 645 596 -49 (-7.60%) 26 24 -2 (-7.69%)
test_xdp_noinline.bpf.linked3.o balancer_ingress_v6 3520 3516 -4 (-0.11%) 216 216 +0 (+0.00%)
xdp_synproxy_kern.bpf.linked3.o syncookie_tc 82661 81241 -1420 (-1.72%) 5073 5155 +82 (+1.62%)
xdp_synproxy_kern.bpf.linked3.o syncookie_xdp 84964 82297 -2667 (-3.14%) 5130 5157 +27 (+0.53%)
META-INTERNAL
=============
Program Insns (A) Insns (B) Insns (DIFF) States (A) States (B) States (DIFF)
-------------------------------------- --------- --------- ----------------- ---------- ---------- ---------------
balancer_ingress 27925 23608 -4317 (-15.46%) 1488 1482 -6 (-0.40%)
balancer_ingress 31824 27546 -4278 (-13.44%) 1658 1652 -6 (-0.36%)
balancer_ingress 32213 27935 -4278 (-13.28%) 1689 1683 -6 (-0.36%)
balancer_ingress 32213 27935 -4278 (-13.28%) 1689 1683 -6 (-0.36%)
balancer_ingress 31824 27546 -4278 (-13.44%) 1658 1652 -6 (-0.36%)
balancer_ingress 38647 29562 -9085 (-23.51%) 2069 1835 -234 (-11.31%)
balancer_ingress 38647 29562 -9085 (-23.51%) 2069 1835 -234 (-11.31%)
balancer_ingress 40339 30792 -9547 (-23.67%) 2193 1934 -259 (-11.81%)
balancer_ingress 37321 29055 -8266 (-22.15%) 1972 1795 -177 (-8.98%)
balancer_ingress 38176 29753 -8423 (-22.06%) 2008 1831 -177 (-8.81%)
balancer_ingress 29193 20910 -8283 (-28.37%) 1599 1422 -177 (-11.07%)
balancer_ingress 30013 21452 -8561 (-28.52%) 1645 1447 -198 (-12.04%)
balancer_ingress 28691 24290 -4401 (-15.34%) 1545 1531 -14 (-0.91%)
balancer_ingress 34223 28965 -5258 (-15.36%) 1984 1875 -109 (-5.49%)
balancer_ingress 35481 26158 -9323 (-26.28%) 2095 1806 -289 (-13.79%)
balancer_ingress 35481 26158 -9323 (-26.28%) 2095 1806 -289 (-13.79%)
balancer_ingress 35868 26455 -9413 (-26.24%) 2140 1827 -313 (-14.63%)
balancer_ingress 35868 26455 -9413 (-26.24%) 2140 1827 -313 (-14.63%)
balancer_ingress 35481 26158 -9323 (-26.28%) 2095 1806 -289 (-13.79%)
balancer_ingress 35481 26158 -9323 (-26.28%) 2095 1806 -289 (-13.79%)
balancer_ingress 34844 29485 -5359 (-15.38%) 2036 1918 -118 (-5.80%)
fbflow_egress 3256 2652 -604 (-18.55%) 218 192 -26 (-11.93%)
fbflow_ingress 1026 944 -82 (-7.99%) 70 63 -7 (-10.00%)
sslwall_tc_egress 8424 7360 -1064 (-12.63%) 498 458 -40 (-8.03%)
syar_accept_protect 15040 9539 -5501 (-36.58%) 364 220 -144 (-39.56%)
syar_connect_tcp_v6 15036 9535 -5501 (-36.59%) 360 216 -144 (-40.00%)
syar_connect_udp_v4 15039 9538 -5501 (-36.58%) 361 217 -144 (-39.89%)
syar_connect_connect4_protect4 24805 15833 -8972 (-36.17%) 756 480 -276 (-36.51%)
syar_lsm_file_open 167772 151813 -15959 (-9.51%) 1836 1667 -169 (-9.20%)
syar_namespace_create_new 14805 9304 -5501 (-37.16%) 353 209 -144 (-40.79%)
syar_python3_detect 17531 12030 -5501 (-31.38%) 391 247 -144 (-36.83%)
syar_ssh_post_fork 16412 10911 -5501 (-33.52%) 405 261 -144 (-35.56%)
syar_enter_execve 14728 9227 -5501 (-37.35%) 345 201 -144 (-41.74%)
syar_enter_execveat 14728 9227 -5501 (-37.35%) 345 201 -144 (-41.74%)
syar_exit_execve 16622 11121 -5501 (-33.09%) 376 232 -144 (-38.30%)
syar_exit_execveat 16622 11121 -5501 (-33.09%) 376 232 -144 (-38.30%)
syar_syscalls_kill 15288 9787 -5501 (-35.98%) 398 254 -144 (-36.18%)
syar_task_enter_pivot_root 14898 9397 -5501 (-36.92%) 357 213 -144 (-40.34%)
syar_syscalls_setreuid 16678 11177 -5501 (-32.98%) 429 285 -144 (-33.57%)
syar_syscalls_setuid 16678 11177 -5501 (-32.98%) 429 285 -144 (-33.57%)
syar_syscalls_process_vm_readv 14959 9458 -5501 (-36.77%) 364 220 -144 (-39.56%)
syar_syscalls_process_vm_writev 15757 10256 -5501 (-34.91%) 390 246 -144 (-36.92%)
do_uprobe 15519 10018 -5501 (-35.45%) 373 229 -144 (-38.61%)
edgewall 179715 55783 -123932 (-68.96%) 12607 3999 -8608 (-68.28%)
bictcp_state 7570 4131 -3439 (-45.43%) 496 269 -227 (-45.77%)
cubictcp_state 7570 4131 -3439 (-45.43%) 496 269 -227 (-45.77%)
tcp_rate_skb_delivered 447 272 -175 (-39.15%) 29 18 -11 (-37.93%)
kprobe__bbr_set_state 4566 2615 -1951 (-42.73%) 209 124 -85 (-40.67%)
kprobe__bictcp_state 4566 2615 -1951 (-42.73%) 209 124 -85 (-40.67%)
inet_sock_set_state 1501 1337 -164 (-10.93%) 93 85 -8 (-8.60%)
tcp_retransmit_skb 1145 981 -164 (-14.32%) 67 59 -8 (-11.94%)
tcp_retransmit_synack 1183 951 -232 (-19.61%) 67 55 -12 (-17.91%)
bpf_tcptuner 1459 1187 -272 (-18.64%) 99 80 -19 (-19.19%)
tw_egress 801 776 -25 (-3.12%) 69 66 -3 (-4.35%)
tw_ingress 795 770 -25 (-3.14%) 69 66 -3 (-4.35%)
ttls_tc_ingress 19025 19383 +358 (+1.88%) 470 465 -5 (-1.06%)
ttls_nat_egress 490 299 -191 (-38.98%) 33 20 -13 (-39.39%)
ttls_nat_ingress 448 285 -163 (-36.38%) 32 21 -11 (-34.38%)
tw_twfw_egress 511127 212071 -299056 (-58.51%) 16733 8504 -8229 (-49.18%)
tw_twfw_ingress 500095 212069 -288026 (-57.59%) 16223 8504 -7719 (-47.58%)
tw_twfw_tc_eg 511113 212064 -299049 (-58.51%) 16732 8504 -8228 (-49.18%)
tw_twfw_tc_in 500095 212069 -288026 (-57.59%) 16223 8504 -7719 (-47.58%)
tw_twfw_egress 12632 12435 -197 (-1.56%) 276 260 -16 (-5.80%)
tw_twfw_ingress 12631 12454 -177 (-1.40%) 278 261 -17 (-6.12%)
tw_twfw_tc_eg 12595 12435 -160 (-1.27%) 274 259 -15 (-5.47%)
tw_twfw_tc_in 12631 12454 -177 (-1.40%) 278 261 -17 (-6.12%)
tw_xdp_dump 266 209 -57 (-21.43%) 9 8 -1 (-11.11%)
CILIUM
=========
File Program Insns (A) Insns (B) Insns (DIFF) States (A) States (B) States (DIFF)
------------- -------------------------------- --------- --------- ---------------- ---------- ---------- --------------
bpf_host.o cil_to_netdev 6047 4578 -1469 (-24.29%) 362 249 -113 (-31.22%)
bpf_host.o handle_lxc_traffic 2227 1585 -642 (-28.83%) 156 103 -53 (-33.97%)
bpf_host.o tail_handle_ipv4_from_netdev 2244 1458 -786 (-35.03%) 163 106 -57 (-34.97%)
bpf_host.o tail_handle_nat_fwd_ipv4 21022 10479 -10543 (-50.15%) 1289 670 -619 (-48.02%)
bpf_host.o tail_handle_nat_fwd_ipv6 15433 11375 -4058 (-26.29%) 905 643 -262 (-28.95%)
bpf_host.o tail_ipv4_host_policy_ingress 2219 1367 -852 (-38.40%) 161 96 -65 (-40.37%)
bpf_host.o tail_nodeport_nat_egress_ipv4 22460 19862 -2598 (-11.57%) 1469 1293 -176 (-11.98%)
bpf_host.o tail_nodeport_nat_ingress_ipv4 5526 3534 -1992 (-36.05%) 366 243 -123 (-33.61%)
bpf_host.o tail_nodeport_nat_ingress_ipv6 5132 4256 -876 (-17.07%) 241 219 -22 (-9.13%)
bpf_host.o tail_nodeport_nat_ipv6_egress 3702 3542 -160 (-4.32%) 215 205 -10 (-4.65%)
bpf_lxc.o tail_handle_nat_fwd_ipv4 21022 10479 -10543 (-50.15%) 1289 670 -619 (-48.02%)
bpf_lxc.o tail_handle_nat_fwd_ipv6 15433 11375 -4058 (-26.29%) 905 643 -262 (-28.95%)
bpf_lxc.o tail_ipv4_ct_egress 5073 3374 -1699 (-33.49%) 262 172 -90 (-34.35%)
bpf_lxc.o tail_ipv4_ct_ingress 5093 3385 -1708 (-33.54%) 262 172 -90 (-34.35%)
bpf_lxc.o tail_ipv4_ct_ingress_policy_only 5093 3385 -1708 (-33.54%) 262 172 -90 (-34.35%)
bpf_lxc.o tail_ipv6_ct_egress 4593 3878 -715 (-15.57%) 194 151 -43 (-22.16%)
bpf_lxc.o tail_ipv6_ct_ingress 4606 3891 -715 (-15.52%) 194 151 -43 (-22.16%)
bpf_lxc.o tail_ipv6_ct_ingress_policy_only 4606 3891 -715 (-15.52%) 194 151 -43 (-22.16%)
bpf_lxc.o tail_nodeport_nat_ingress_ipv4 5526 3534 -1992 (-36.05%) 366 243 -123 (-33.61%)
bpf_lxc.o tail_nodeport_nat_ingress_ipv6 5132 4256 -876 (-17.07%) 241 219 -22 (-9.13%)
bpf_overlay.o tail_handle_nat_fwd_ipv4 20524 10114 -10410 (-50.72%) 1271 638 -633 (-49.80%)
bpf_overlay.o tail_nodeport_nat_egress_ipv4 22718 19490 -3228 (-14.21%) 1475 1275 -200 (-13.56%)
bpf_overlay.o tail_nodeport_nat_ingress_ipv4 5526 3534 -1992 (-36.05%) 366 243 -123 (-33.61%)
bpf_overlay.o tail_nodeport_nat_ingress_ipv6 5132 4256 -876 (-17.07%) 241 219 -22 (-9.13%)
bpf_overlay.o tail_nodeport_nat_ipv6_egress 3638 3548 -90 (-2.47%) 209 203 -6 (-2.87%)
bpf_overlay.o tail_rev_nodeport_lb4 4368 3820 -548 (-12.55%) 248 215 -33 (-13.31%)
bpf_overlay.o tail_rev_nodeport_lb6 2867 2428 -439 (-15.31%) 167 140 -27 (-16.17%)
bpf_sock.o cil_sock6_connect 1718 1703 -15 (-0.87%) 100 99 -1 (-1.00%)
bpf_xdp.o tail_handle_nat_fwd_ipv4 12917 12443 -474 (-3.67%) 875 849 -26 (-2.97%)
bpf_xdp.o tail_handle_nat_fwd_ipv6 13515 13264 -251 (-1.86%) 715 702 -13 (-1.82%)
bpf_xdp.o tail_lb_ipv4 39492 36367 -3125 (-7.91%) 2430 2251 -179 (-7.37%)
bpf_xdp.o tail_lb_ipv6 80441 78058 -2383 (-2.96%) 3647 3523 -124 (-3.40%)
bpf_xdp.o tail_nodeport_ipv6_dsr 1038 901 -137 (-13.20%) 61 55 -6 (-9.84%)
bpf_xdp.o tail_nodeport_nat_egress_ipv4 13027 12096 -931 (-7.15%) 868 809 -59 (-6.80%)
bpf_xdp.o tail_nodeport_nat_ingress_ipv4 7617 5900 -1717 (-22.54%) 522 413 -109 (-20.88%)
bpf_xdp.o tail_nodeport_nat_ingress_ipv6 7575 7395 -180 (-2.38%) 383 374 -9 (-2.35%)
bpf_xdp.o tail_rev_nodeport_lb4 6808 6739 -69 (-1.01%) 403 396 -7 (-1.74%)
bpf_xdp.o tail_rev_nodeport_lb6 16173 15847 -326 (-2.02%) 1010 990 -20 (-1.98%)
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231205184248.1502704-9-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
|
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[ Upstream commit e322f0bcb8d371f4606eaf141c7f967e1a79bcb7 ]
Similar to special handling of STACK_ZERO, when reading 1/2/4 bytes from
stack from slot that has register spilled into it and that register has
a constant value zero, preserve that zero and mark spilled register as
precise for that. This makes spilled const zero register and STACK_ZERO
cases equivalent in their behavior.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231205184248.1502704-7-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit eaf18febd6ebc381aeb61543705148b3e28c7c47 ]
Instead of always forcing STACK_ZERO slots to STACK_MISC, preserve it in
situations where this is possible. E.g., when spilling register as
1/2/4-byte subslots on the stack, all the remaining bytes in the stack
slot do not automatically become unknown. If we knew they contained
zeroes, we can preserve those STACK_ZERO markers.
Add a helper mark_stack_slot_misc(), similar to scrub_spilled_slot(),
but that doesn't overwrite either STACK_INVALID nor STACK_ZERO. Note
that we need to take into account possibility of being in unprivileged
mode, in which case STACK_INVALID is forced to STACK_MISC for correctness,
as treating STACK_INVALID as equivalent STACK_MISC is only enabled in
privileged mode.
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231205184248.1502704-5-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 41f6f64e6999a837048b1bd13a2f8742964eca6b ]
Use instruction (jump) history to record instructions that performed
register spill/fill to/from stack, regardless if this was done through
read-only r10 register, or any other register after copying r10 into it
*and* potentially adjusting offset.
To make this work reliably, we push extra per-instruction flags into
instruction history, encoding stack slot index (spi) and stack frame
number in extra 10 bit flags we take away from prev_idx in instruction
history. We don't touch idx field for maximum performance, as it's
checked most frequently during backtracking.
This change removes basically the last remaining practical limitation of
precision backtracking logic in BPF verifier. It fixes known
deficiencies, but also opens up new opportunities to reduce number of
verified states, explored in the subsequent patches.
There are only three differences in selftests' BPF object files
according to veristat, all in the positive direction (less states).
File Program Insns (A) Insns (B) Insns (DIFF) States (A) States (B) States (DIFF)
-------------------------------------- ------------- --------- --------- ------------- ---------- ---------- -------------
test_cls_redirect_dynptr.bpf.linked3.o cls_redirect 2987 2864 -123 (-4.12%) 240 231 -9 (-3.75%)
xdp_synproxy_kern.bpf.linked3.o syncookie_tc 82848 82661 -187 (-0.23%) 5107 5073 -34 (-0.67%)
xdp_synproxy_kern.bpf.linked3.o syncookie_xdp 85116 84964 -152 (-0.18%) 5162 5130 -32 (-0.62%)
Note, I avoided renaming jmp_history to more generic insn_hist to
minimize number of lines changed and potential merge conflicts between
bpf and bpf-next trees.
Notice also cur_hist_entry pointer reset to NULL at the beginning of
instruction verification loop. This pointer avoids the problem of
relying on last jump history entry's insn_idx to determine whether we
already have entry for current instruction or not. It can happen that we
added jump history entry because current instruction is_jmp_point(), but
also we need to add instruction flags for stack access. In this case, we
don't want to entries, so we need to reuse last added entry, if it is
present.
Relying on insn_idx comparison has the same ambiguity problem as the one
that was fixed recently in [0], so we avoid that.
[0] https://patchwork.kernel.org/project/netdevbpf/patch/20231110002638.4168352-3-andrii@kernel.org/
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Reported-by: Tao Lyu <tao.lyu@epfl.ch>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20231205184248.1502704-2-andrii@kernel.org
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
[ Note: Adapted the expected log format for selftests as the map format
in verifier logs was changed in commits 1db747d75b1d and
0c95c9fdb696. ]
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 3bfdc63936dd4773109b7b8c280c0f3b5ae7d349 upstream.
remove_waiter() is used by the slowlock paths, but it is also used for
proxy-lock rollback in rt_mutex_start_proxy_lock() when invoked from
futex_requeue().
In the latter case waiter::task is not current, but remove_waiter()
operates on current for the dequeue operation. That results in several
problems:
1) the rbtree dequeue happens without waiter::task::pi_lock being held
2) the waiter task's pi_blocked_on state is not cleared, which leaves a
dangling pointer primed for UAF around.
3) rt_mutex_adjust_prio_chain() operates on the wrong top priority waiter
task
Use waiter::task instead of current in all related operations in
remove_waiter() to cure those problems.
[ tglx: Fixup rt_mutex_adjust_prio_chain(), add a comment and amend the
changelog ]
Fixes: 8161239a8bcc ("rtmutex: Simplify PI algorithm and make highest prio task get lock")
Reported-by: Yuan Tan <yuantan098@gmail.com>
Reported-by: Yifan Wu <yifanwucs@gmail.com>
Reported-by: Juefei Pu <tomapufckgml@gmail.com>
Reported-by: Xin Liu <bird@lzu.edu.cn>
Signed-off-by: Keenan Dong <keenanat2000@gmail.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 16c4f0211aaa1ec1422b11b59f64f1abe9009fc0 upstream.
delay accounting started populating taskstats records with a valid version
field via fill_pid() and fill_tgid().
Later, commit ad4ecbcba728 ("[PATCH] delay accounting taskstats interface
send tgid once") changed the TGID exit path to send the cached
signal->stats aggregate directly instead of building the outgoing record
through fill_tgid(). Unlike fill_tgid(), fill_tgid_exit() only
accumulates accounting data and never initializes stats->version.
As a result, TGID exit notifications can reach userspace with version == 0
even though PID exit notifications and TASKSTATS_CMD_GET replies carry a
valid taskstats version.
This is easy to reproduce with `tools/accounting/getdelays.c`.
I have a small follow-up patch for that tool which:
1. increases the receive buffer/message size so the pid+tgid
combined exit notification is not dropped/truncated
2. prints `stats->version`.
With that patch, the reproducer is:
Terminal 1:
./getdelays -d -v -l -m 0
Terminal 2:
taskset -c 0 python3 -c 'import threading,time; t=threading.Thread(target=time.sleep,args=(0.1,)); t.start(); t.join()'
That produces both PID and TGID exit notifications for the same
process. The PID exit record reports a valid taskstats version, while
the TGID exit record reports `version 0`.
This patch (of 2):
Set stats->version = TASKSTATS_VERSION after copying the cached TGID
aggregate into the outgoing netlink payload so all taskstats records are
self-describing again.
Link: https://lkml.kernel.org/r/ba83d934e59edd431b693607de573eb9ca059309.1774810498.git.cyyzero16@gmail.com
Fixes: ad4ecbcba728 ("[PATCH] delay accounting taskstats interface send tgid once")
Signed-off-by: Yiyang Chen <cyyzero16@gmail.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Dr. Thomas Orgis <thomas.orgis@uni-hamburg.de>
Cc: Fan Yu <fan.yu9@zte.com.cn>
Cc: Wang Yaxin <wang.yaxin@zte.com.cn>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 37beb42560165869838e7d91724f3e629db64129 upstream.
kstack_offset was previously maintained per-cpu, but this caused a
couple of issues. So let's instead make it per-task.
Issue 1: add_random_kstack_offset() and choose_random_kstack_offset()
expected and required to be called with interrupts and preemption
disabled so that it could manipulate per-cpu state. But arm64, loongarch
and risc-v are calling them with interrupts and preemption enabled. I
don't _think_ this causes any functional issues, but it's certainly
unexpected and could lead to manipulating the wrong cpu's state, which
could cause a minor performance degradation due to bouncing the cache
lines. By maintaining the state per-task those functions can safely be
called in preemptible context.
Issue 2: add_random_kstack_offset() is called before executing the
syscall and expands the stack using a previously chosen random offset.
choose_random_kstack_offset() is called after executing the syscall and
chooses and stores a new random offset for the next syscall. With
per-cpu storage for this offset, an attacker could force cpu migration
during the execution of the syscall and prevent the offset from being
updated for the original cpu such that it is predictable for the next
syscall on that cpu. By maintaining the state per-task, this problem
goes away because the per-task random offset is updated after the
syscall regardless of which cpu it is executing on.
Fixes: 39218ff4c625 ("stack: Optionally randomize kernel stack offset each syscall")
Closes: https://lore.kernel.org/all/dd8c37bc-795f-4c7a-9086-69e584d8ab24@arm.com/
Cc: stable@vger.kernel.org
Acked-by: Mark Rutland <mark.rutland@arm.com>
Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Link: https://patch.msgid.link/20260303150840.3789438-2-ryan.roberts@arm.com
Signed-off-by: Kees Cook <kees@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6b839b3b76cf17296ebd4a893841f32cae08229c upstream.
While browsing through ChromeOS crash reports, I found one with an
allocation failure that looked like this:
chrome: page allocation failure: order:7,
mode:0x40dc0(GFP_KERNEL|__GFP_COMP|__GFP_ZERO),
nodemask=(null),cpuset=urgent,mems_allowed=0
CPU: 7 PID: 3295 Comm: chrome Not tainted
5.15.133-20574-g8044615ac35c #1 (HASH:1162 1)
Hardware name: Google Lazor (rev3 - 8) with KB Backlight (DT)
Call trace:
...
warn_alloc+0x104/0x174
__alloc_pages+0x5f0/0x6e4
kmalloc_order+0x44/0x98
kmalloc_order_trace+0x34/0x124
__kmalloc+0x228/0x36c
__regset_get+0x68/0xcc
regset_get_alloc+0x1c/0x28
elf_core_dump+0x3d8/0xd8c
do_coredump+0xeb8/0x1378
get_signal+0x14c/0x804
...
An order 7 allocation is (1 << 7) contiguous pages, or 512K. It's not
a surprise that this allocation failed on a system that's been running
for a while.
More digging showed that it was fairly easy to see the order 7
allocation by just sending a SIGQUIT to chrome (or other processes) to
generate a core dump. The actual amount being allocated was 279,584
bytes and it was for "core_note_type" NT_ARM_SVE.
There was quite a bit of discussion [1] on the mailing lists in
response to my v1 patch attempting to switch to vmalloc. The overall
conclusion was that we could likely reduce the 279,584 byte allocation
by quite a bit and Mark Brown has sent a patch to that effect [2].
However even with the 279,584 byte allocation gone there are still
65,552 byte allocations. These are just barely more than the 65,536
bytes and thus would require an order 5 allocation.
An order 5 allocation is still something to avoid unless necessary and
nothing needs the memory here to be contiguous. Change the allocation
to kvzalloc() which should still be efficient for small allocations
but doesn't force the memory subsystem to work hard (and maybe fail)
at getting a large contiguous chunk.
[1] https://lore.kernel.org/r/20240201171159.1.Id9ad163b60d21c9e56c2d686b0cc9083a8ba7924@changeid
[2] https://lore.kernel.org/r/20240203-arm64-sve-ptrace-regset-size-v1-1-2c3ba1386b9e@kernel.org
Link: https://lkml.kernel.org/r/20240205092626.v2.1.Id9ad163b60d21c9e56c2d686b0cc9083a8ba7924@changeid
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>
Cc: Al Viro <viro@ZenIV.linux.org.uk>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Dave Martin <Dave.Martin@arm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Kees Cook <keescook@chromium.org>
Cc: Mark Brown <broonie@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Wen Yang <wen.yang@linux.dev>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 71203f68c7749609d7fc8ae6ad054bdedeb24f91 ]
There is a race condition/UAF in padata_reorder that goes back
to the initial commit. A reference count is taken at the start
of the process in padata_do_parallel, and released at the end in
padata_serial_worker.
This reference count is (and only is) required for padata_replace
to function correctly. If padata_replace is never called then
there is no issue.
In the function padata_reorder which serves as the core of padata,
as soon as padata is added to queue->serial.list, and the associated
spin lock released, that padata may be processed and the reference
count on pd would go away.
Fix this by getting the next padata before the squeue->serial lock
is released.
In order to make this possible, simplify padata_reorder by only
calling it once the next padata arrives.
Fixes: 16295bec6398 ("padata: Generic parallelization/serialization interface")
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
[ Adjust context of padata_find_next(). Replace
cpumask_next_wrap(cpu, pd->cpumask.pcpu) with
cpumask_next_wrap(cpu, pd->cpumask.pcpu, -1, false) in padata_reorder() in
v6.6 according to dc5bb9b769c9 ("cpumask: deprecate cpumask_next_wrap()") and
f954a2d37637 ("padata: switch padata_find_next() to using cpumask_next_wrap()")
. ]
Signed-off-by: Bin Lan <lanbincn@139.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 31e62c2ebbfdc3fe3dbdf5e02c92a9dc67087a3a upstream.
The 'dumpability' of a task is fundamentally about the memory image of
the task - the concept comes from whether it can core dump or not - and
makes no sense when you don't have an associated mm.
And almost all users do in fact use it only for the case where the task
has a mm pointer.
But we have one odd special case: ptrace_may_access() uses 'dumpable' to
check various other things entirely independently of the MM (typically
explicitly using flags like PTRACE_MODE_READ_FSCREDS). Including for
threads that no longer have a VM (and maybe never did, like most kernel
threads).
It's not what this flag was designed for, but it is what it is.
The ptrace code does check that the uid/gid matches, so you do have to
be uid-0 to see kernel thread details, but this means that the
traditional "drop capabilities" model doesn't make any difference for
this all.
Make it all make a *bit* more sense by saying that if you don't have a
MM pointer, we'll use a cached "last dumpability" flag if the thread
ever had a MM (it will be zero for kernel threads since it is never
set), and require a proper CAP_SYS_PTRACE capability to override.
Reported-by: Qualys Security Advisory <qsa@qualys.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Kees Cook <kees@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit da46b5dfef48658d03347cda21532bcdbb521e67 ]
tracing_record_cmdline() internally uses __this_cpu_read() and
__this_cpu_write() on the per-CPU variable trace_cmdline_save, and
trace_save_cmdline() explicitly asserts preemption is disabled via
lockdep_assert_preemption_disabled(). These operations are only safe
when preemption is off, as they were designed to be called from the
scheduler context (probe_wakeup_sched_switch() / probe_wakeup()).
__blk_add_trace() was calling tracing_record_cmdline(current) early in
the blk_tracer path, before ring buffer reservation, from process
context where preemption is fully enabled. This triggers the following
using blktests/blktrace/002:
blktrace/002 (blktrace ftrace corruption with sysfs trace) [failed]
runtime 0.367s ... 0.437s
something found in dmesg:
[ 81.211018] run blktests blktrace/002 at 2026-02-25 22:24:33
[ 81.239580] null_blk: disk nullb1 created
[ 81.357294] BUG: using __this_cpu_read() in preemptible [00000000] code: dd/2516
[ 81.362842] caller is tracing_record_cmdline+0x10/0x40
[ 81.362872] CPU: 16 UID: 0 PID: 2516 Comm: dd Tainted: G N 7.0.0-rc1lblk+ #84 PREEMPT(full)
[ 81.362877] Tainted: [N]=TEST
[ 81.362878] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
[ 81.362881] Call Trace:
[ 81.362884] <TASK>
[ 81.362886] dump_stack_lvl+0x8d/0xb0
...
(See '/mnt/sda/blktests/results/nodev/blktrace/002.dmesg' for the entire message)
[ 81.211018] run blktests blktrace/002 at 2026-02-25 22:24:33
[ 81.239580] null_blk: disk nullb1 created
[ 81.357294] BUG: using __this_cpu_read() in preemptible [00000000] code: dd/2516
[ 81.362842] caller is tracing_record_cmdline+0x10/0x40
[ 81.362872] CPU: 16 UID: 0 PID: 2516 Comm: dd Tainted: G N 7.0.0-rc1lblk+ #84 PREEMPT(full)
[ 81.362877] Tainted: [N]=TEST
[ 81.362878] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.17.0-0-gb52ca86e094d-prebuilt.qemu.org 04/01/2014
[ 81.362881] Call Trace:
[ 81.362884] <TASK>
[ 81.362886] dump_stack_lvl+0x8d/0xb0
[ 81.362895] check_preemption_disabled+0xce/0xe0
[ 81.362902] tracing_record_cmdline+0x10/0x40
[ 81.362923] __blk_add_trace+0x307/0x5d0
[ 81.362934] ? lock_acquire+0xe0/0x300
[ 81.362940] ? iov_iter_extract_pages+0x101/0xa30
[ 81.362959] blk_add_trace_bio+0x106/0x1e0
[ 81.362968] submit_bio_noacct_nocheck+0x24b/0x3a0
[ 81.362979] ? lockdep_init_map_type+0x58/0x260
[ 81.362988] submit_bio_wait+0x56/0x90
[ 81.363009] __blkdev_direct_IO_simple+0x16c/0x250
[ 81.363026] ? __pfx_submit_bio_wait_endio+0x10/0x10
[ 81.363038] ? rcu_read_lock_any_held+0x73/0xa0
[ 81.363051] blkdev_read_iter+0xc1/0x140
[ 81.363059] vfs_read+0x20b/0x330
[ 81.363083] ksys_read+0x67/0xe0
[ 81.363090] do_syscall_64+0xbf/0xf00
[ 81.363102] entry_SYSCALL_64_after_hwframe+0x76/0x7e
[ 81.363106] RIP: 0033:0x7f281906029d
[ 81.363111] Code: 31 c0 e9 c6 fe ff ff 50 48 8d 3d 66 63 0a 00 e8 59 ff 01 00 66 0f 1f 84 00 00 00 00 00 80 3d 41 33 0e 00 00 74 17 31 c0 0f 05 <48> 3d 00 f0 ff ff 77 5b c3 66 2e 0f 1f 84 00 00 00 00 00 48 83 ec
[ 81.363113] RSP: 002b:00007ffca127dd48 EFLAGS: 00000246 ORIG_RAX: 0000000000000000
[ 81.363120] RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f281906029d
[ 81.363122] RDX: 0000000000001000 RSI: 0000559f8bfae000 RDI: 0000000000000000
[ 81.363123] RBP: 0000000000001000 R08: 0000002863a10a81 R09: 00007f281915f000
[ 81.363124] R10: 00007f2818f77b60 R11: 0000000000000246 R12: 0000559f8bfae000
[ 81.363126] R13: 0000000000000000 R14: 0000000000000000 R15: 000000000000000a
[ 81.363142] </TASK>
The same BUG fires from blk_add_trace_plug(), blk_add_trace_unplug(),
and blk_add_trace_rq() paths as well.
The purpose of tracing_record_cmdline() is to cache the task->comm for
a given PID so that the trace can later resolve it. It is only
meaningful when a trace event is actually being recorded. Ring buffer
reservation via ring_buffer_lock_reserve() disables preemption, and
preemption remains disabled until the event is committed :-
__blk_add_trace()
__trace_buffer_lock_reserve()
__trace_buffer_lock_reserve()
ring_buffer_lock_reserve()
preempt_disable_notrace(); <---
With this fix blktests for blktrace pass:
blktests (master) # ./check blktrace
blktrace/001 (blktrace zone management command tracing) [passed]
runtime 3.650s ... 3.647s
blktrace/002 (blktrace ftrace corruption with sysfs trace) [passed]
runtime 0.411s ... 0.384s
Fixes: 7ffbd48d5cab ("tracing: Cache comms only after an event occurred")
Reported-by: Shinichiro Kawasaki <shinichiro.kawasaki@wdc.com>
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Rajani Kantha <681739313@139.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 4346be6577aaa04586167402ae87bbdbe32484a4 ]
parse_probe_arg() accepts quoted immediate strings and passes the body
after the opening quote to __parse_imm_string(). That helper currently
computes strlen(str) and immediately dereferences str[len - 1], which
underflows when the body is empty and not closed with double-quotation.
Reject empty non-closed immediate strings before checking for the closing quote.
Link: https://lore.kernel.org/all/20260401160315.88518-1-pengpeng@iscas.ac.cn/
Fixes: a42e3c4de964 ("tracing/probe: Add immediate string parameter support")
Signed-off-by: Pengpeng Hou <pengpeng@iscas.ac.cn>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 35e351780fa9d8240dd6f7e4f245f9ea37e96c19 ]
Thorvald reported a WARNING [1]. And the root cause is below race:
CPU 1 CPU 2
fork hugetlbfs_fallocate
dup_mmap hugetlbfs_punch_hole
i_mmap_lock_write(mapping);
vma_interval_tree_insert_after -- Child vma is visible through i_mmap tree.
i_mmap_unlock_write(mapping);
hugetlb_dup_vma_private -- Clear vma_lock outside i_mmap_rwsem!
i_mmap_lock_write(mapping);
hugetlb_vmdelete_list
vma_interval_tree_foreach
hugetlb_vma_trylock_write -- Vma_lock is cleared.
tmp->vm_ops->open -- Alloc new vma_lock outside i_mmap_rwsem!
hugetlb_vma_unlock_write -- Vma_lock is assigned!!!
i_mmap_unlock_write(mapping);
hugetlb_dup_vma_private() and hugetlb_vm_op_open() are called outside
i_mmap_rwsem lock while vma lock can be used in the same time. Fix this
by deferring linking file vma until vma is fully initialized. Those vmas
should be initialized first before they can be used.
[tk: Adapted to 6.6 stable where vma_iter_bulk_store() can fail
(unlike mainline which uses __mt_dup() for pre-allocation).
Preserved error handling via goto fail_nomem_vmi_store. Previous
backport (cec11fa2eb512) was reverted (dd782da470761) due to
xfstests failures.]
Link: https://lkml.kernel.org/r/20240410091441.3539905-1-linmiaohe@huawei.com
Fixes: 8d9bfb260814 ("hugetlb: add vma based lock for pmd sharing")
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reported-by: Thorvald Natvig <thorvald@google.com>
Closes: https://lore.kernel.org/linux-mm/20240129161735.6gmjsswx62o4pbja@revolver/T/ [1]
Reviewed-by: Jane Chu <jane.chu@oracle.com>
Cc: Christian Brauner <brauner@kernel.org>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Kent Overstreet <kent.overstreet@linux.dev>
Cc: Liam R. Howlett <Liam.Howlett@oracle.com>
Cc: Mateusz Guzik <mjguzik@gmail.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Miaohe Lin <linmiaohe@huawei.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peng Zhang <zhangpeng.00@bytedance.com>
Cc: Tycho Andersen <tandersen@netflix.com>
Cc: stable@vger.kernel.org
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Assisted-by: Claude:claude-opus-4.6
Suggested-by: David Nyström <david.nystrom@est.tech>
Signed-off-by: Tugrul Kukul <tugrul.kukul@est.tech>
Acked-by: Alex Williamson <alex@shazbot.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit b0db1accbc7395657c2b79db59fa9fae0d6656f3 ]
check_mem_access() matches PTR_TO_BUF via base_type() which strips
PTR_MAYBE_NULL, allowing direct dereference without a null check.
Map iterator ctx->key and ctx->value are PTR_TO_BUF | PTR_MAYBE_NULL.
On stop callbacks these are NULL, causing a kernel NULL dereference.
Add a type_may_be_null() guard to the PTR_TO_BUF branch, matching the
existing PTR_TO_BTF_ID pattern.
Fixes: 20b2aff4bc15 ("bpf: Introduce MEM_RDONLY flag")
Signed-off-by: Qi Tang <tpluszz77@gmail.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260402092923.38357-2-tpluszz77@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit a8502a79e832b861e99218cbd2d8f4312d62e225 ]
In case rold->reg->range == BEYOND_PKT_END && rcur->reg->range == N
regsafe() may return true which may lead to current state with
valid packet range not being explored. Fix the bug.
Fixes: 6d94e741a8ff ("bpf: Support for pointers beyond pkt_end.")
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Reviewed-by: Daniel Borkmann <daniel@iogearbox.net>
Reviewed-by: Amery Hung <ameryhung@gmail.com>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Link: https://lore.kernel.org/bpf/20260331204228.26726-1-alexei.starovoitov@gmail.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit 210d36d892de5195e6766c45519dfb1e65f3eb83 upstream.
Fuzzying/stressing futexes triggered:
WARNING: kernel/futex/core.c:825 at wait_for_owner_exiting+0x7a/0x80, CPU#11: futex_lock_pi_s/524
When futex_lock_pi_atomic() sees the owner is exiting, it returns -EBUSY
and stores a refcounted task pointer in 'exiting'.
After wait_for_owner_exiting() consumes that reference, the local pointer
is never reset to nil. Upon a retry, if futex_lock_pi_atomic() returns a
different error, the bogus pointer is passed to wait_for_owner_exiting().
CPU0 CPU1 CPU2
futex_lock_pi(uaddr)
// acquires the PI futex
exit()
futex_cleanup_begin()
futex_state = EXITING;
futex_lock_pi(uaddr)
futex_lock_pi_atomic()
attach_to_pi_owner()
// observes EXITING
*exiting = owner; // takes ref
return -EBUSY
wait_for_owner_exiting(-EBUSY, owner)
put_task_struct(); // drops ref
// exiting still points to owner
goto retry;
futex_lock_pi_atomic()
lock_pi_update_atomic()
cmpxchg(uaddr)
*uaddr ^= WAITERS // whatever
// value changed
return -EAGAIN;
wait_for_owner_exiting(-EAGAIN, exiting) // stale
WARN_ON_ONCE(exiting)
Fix this by resetting upon retry, essentially aligning it with requeue_pi.
Fixes: 3ef240eaff36 ("futex: Prevent exit livelock")
Signed-off-by: Davidlohr Bueso <dave@stgolabs.net>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260326001759.4129680-1-dave@stgolabs.net
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 1f9885732248d22f788e4992c739a98c88ab8a55 ]
The following sequence may leads deadlock in cpu hotplug:
task1 task2 task3
----- ----- -----
mutex_lock(&interface_lock)
[CPU GOING OFFLINE]
cpus_write_lock();
osnoise_cpu_die();
kthread_stop(task3);
wait_for_completion();
osnoise_sleep();
mutex_lock(&interface_lock);
cpus_read_lock();
[DEAD LOCK]
Fix by swap the order of cpus_read_lock() and mutex_lock(&interface_lock).
Cc: stable@vger.kernel.org
Cc: <mathieu.desnoyers@efficios.com>
Cc: <zhang.run@zte.com.cn>
Cc: <yang.tao172@zte.com.cn>
Cc: <ran.xiaokai@zte.com.cn>
Fixes: bce29ac9ce0bb ("trace: Add osnoise tracer")
Link: https://patch.msgid.link/20260326141953414bVSj33dAYktqp9Oiyizq8@zte.com.cn
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Luo Haiyang <luo.haiyang@zte.com.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 930d2b32c0af6895ba4c6ca6404e7f7b6dc214ed ]
The osnoise_hotplug_workfn() grabs two mutexes and cpu_read_lock(). It has
various gotos to handle unlocking them. Switch them over to guard() and
let the compiler worry about it.
The osnoise_cpus_read() has a temporary mask_str allocated and there's
some gotos to make sure it gets freed on error paths. Switch that over to
__free() to let the compiler worry about it.
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lore.kernel.org/20241225222931.517329690@goodmis.org
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Stable-dep-of: 1f9885732248 ("tracing: Fix potential deadlock in cpu hotplug with osnoise")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5d16467ae56343b9205caedf85e3a131e0914ad8 upstream.
alarm_timer_forward() passes arguments to alarm_forward() in the wrong
order:
alarm_forward(alarm, timr->it_interval, now);
However, alarm_forward() is defined as:
u64 alarm_forward(struct alarm *alarm, ktime_t now, ktime_t interval);
and uses the second argument as the current time:
delta = ktime_sub(now, alarm->node.expires);
Passing the interval as "now" results in incorrect delta computation,
which can lead to missed expirations or incorrect overrun accounting.
This issue has been present since the introduction of
alarm_timer_forward().
Fix this by swapping the arguments.
Fixes: e7561f1633ac ("alarmtimer: Implement forward callback")
Signed-off-by: Zhan Xusheng <zhanxusheng@xiaomi.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260323061130.29991-1-zhanxusheng@xiaomi.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit f63a9df7e3f9f842945d292a19d9938924f066f9 ]
proc_do_large_bitmap() does not initialize variable c, which is expected
to be set to a trailing character by proc_get_long().
However, proc_get_long() only sets c when the input buffer contains a
trailing character after the parsed value.
If c is not initialized it may happen to contain a '-'. If this is the
case proc_do_large_bitmap() expects to be able to parse a second part of
the input buffer. If there is no second part an unjustified -EINVAL will
be returned.
Initialize c to 0 to prevent returning -EINVAL on valid input.
Fixes: 9f977fb7ae9d ("sysctl: add proc_do_large_bitmap")
Signed-off-by: Marc Buerg <buermarc@googlemail.com>
Reviewed-by: Joel Granados <joel.granados@kernel.org>
Signed-off-by: Joel Granados <joel.granados@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 734eba62cd32cb9ceffa09e57cdc03d761528525 ]
Commit 005e8dddd497 ("PM: hibernate: don't store zero pages in the
image file") added an optimization to skip zero-filled pages in the
hibernation image. On restore, zero pages are handled internally by
snapshot_write_next() in a loop that processes them without returning
to the caller.
With the userspace restore interface, writing the last non-zero page
to /dev/snapshot is followed by the SNAPSHOT_ATOMIC_RESTORE ioctl. At
this point there are no more calls to snapshot_write_next() so any
trailing zero pages are not processed, snapshot_image_loaded() fails
because handle->cur is smaller than expected, the ioctl returns -EPERM
and the image is not restored.
The in-kernel restore path is not affected by this because the loop in
load_image() in swap.c calls snapshot_write_next() until it returns 0.
It is this final call that drains any trailing zero pages.
Fixed by calling snapshot_write_next() in snapshot_write_finalize(),
giving the kernel the chance to drain any trailing zero pages.
Fixes: 005e8dddd497 ("PM: hibernate: don't store zero pages in the image file")
Signed-off-by: Alberto Garcia <berto@igalia.com>
Acked-by: Brian Geffon <bgeffon@google.com>
Link: https://patch.msgid.link/ef5a7c5e3e3dbd17dcb20efaa0c53a47a23498bb.1773075892.git.berto@igalia.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit f4311756a83fb01c28a9bf841cbb7eb2b318eebf ]
set_memory_ro() and set_memory_rw() can fail, leaving memory
unprotected.
Take the returned value into account and abort in case of
failure.
Signed-off-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Reviewed-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Stable-dep-of: 734eba62cd32 ("PM: hibernate: Drain trailing zero pages on userspace restore")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 6f770b73d0311a5b099277653199bb6421c4fed2 ]
When a device performs DMA to a bounce buffer, KMSAN is unaware of
the write and does not mark the data as initialized. When
swiotlb_bounce() later copies the bounce buffer back to the original
buffer, memcpy propagates the uninitialized shadow to the original
buffer, causing false positive uninit-value reports.
Fix this by calling kmsan_unpoison_memory() on the bounce buffer
before copying it back in the DMA_FROM_DEVICE path, so that memcpy
naturally propagates initialized shadow to the destination.
Suggested-by: Alexander Potapenko <glider@google.com>
Link: https://lore.kernel.org/CAG_fn=WUGta-paG1BgsGRoAR+fmuCgh3xo=R3XdzOt_-DqSdHw@mail.gmail.com/
Fixes: 7ade4f10779c ("dma: kmsan: unpoison DMA mappings")
Signed-off-by: Shigeru Yoshida <syoshida@redhat.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260315082750.2375581-1-syoshida@redhat.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit f9d69d5e7bde2295eb7488a56f094ac8f5383b92 ]
The module loader doesn't check for bounds of the ELF section index in
simplify_symbols():
for (i = 1; i < symsec->sh_size / sizeof(Elf_Sym); i++) {
const char *name = info->strtab + sym[i].st_name;
switch (sym[i].st_shndx) {
case SHN_COMMON:
[...]
default:
/* Divert to percpu allocation if a percpu var. */
if (sym[i].st_shndx == info->index.pcpu)
secbase = (unsigned long)mod_percpu(mod);
else
/** HERE --> **/ secbase = info->sechdrs[sym[i].st_shndx].sh_addr;
sym[i].st_value += secbase;
break;
}
}
A symbol with an out-of-bounds st_shndx value, for example 0xffff
(known as SHN_XINDEX or SHN_HIRESERVE), may cause a kernel panic:
BUG: unable to handle page fault for address: ...
RIP: 0010:simplify_symbols+0x2b2/0x480
...
Kernel panic - not syncing: Fatal exception
This can happen when module ELF is legitimately using SHN_XINDEX or
when it is corrupted.
Add a bounds check in simplify_symbols() to validate that st_shndx is
within the valid range before using it.
This issue was discovered due to a bug in llvm-objcopy, see relevant
discussion for details [1].
[1] https://lore.kernel.org/linux-modules/20251224005752.201911-1-ihor.solodrai@linux.dev/
Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
Reviewed-by: Daniel Gomez <da.gomez@samsung.com>
Reviewed-by: Petr Pavlu <petr.pavlu@suse.com>
Signed-off-by: Sami Tolvanen <samitolvanen@google.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit c77b30bd1dcb61f66c640ff7d2757816210c7cb0 ]
The BPF interpreter's signed 32-bit division and modulo handlers use
the kernel abs() macro on s32 operands. The abs() macro documentation
(include/linux/math.h) explicitly states the result is undefined when
the input is the type minimum. When DST contains S32_MIN (0x80000000),
abs((s32)DST) triggers undefined behavior and returns S32_MIN unchanged
on arm64/x86. This value is then sign-extended to u64 as
0xFFFFFFFF80000000, causing do_div() to compute the wrong result.
The verifier's abstract interpretation (scalar32_min_max_sdiv) computes
the mathematically correct result for range tracking, creating a
verifier/interpreter mismatch that can be exploited for out-of-bounds
map value access.
Introduce abs_s32() which handles S32_MIN correctly by casting to u32
before negating, avoiding signed overflow entirely. Replace all 8
abs((s32)...) call sites in the interpreter's sdiv32/smod32 handlers.
s32 is the only affected case -- the s64 division/modulo handlers do
not use abs().
Fixes: ec0e2da95f72 ("bpf: Support new signed div/mod instructions.")
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Mykyta Yatsenko <yatsenko@meta.com>
Signed-off-by: Jenny Guanni Qu <qguanni@gmail.com>
Link: https://lore.kernel.org/r/20260311011116.2108005-2-qguanni@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 146bd2a87a65aa407bb17fac70d8d583d19aba06 ]
Gregory reported in [0] that the global_map_resize test when run in
repeatedly ends up failing during program load. This stems from the fact
that BTF reference has not dropped to zero after the previous run's
module is unloaded, and the older module's BTF is still discoverable and
visible. Later, in libbpf, load_module_btfs() will find the ID for this
stale BTF, open its fd, and then it will be used during program load
where later steps taking module reference using btf_try_get_module()
fail since the underlying module for the BTF is gone.
Logically, once a module is unloaded, it's associated BTF artifacts
should become hidden. The BTF object inside the kernel may still remain
alive as long its reference counts are alive, but it should no longer be
discoverable.
To fix this, let us call btf_free_id() from the MODULE_STATE_GOING case
for the module unload to free the BTF associated IDR entry, and disable
its discovery once module unload returns to user space. If a race
happens during unload, the outcome is non-deterministic anyway. However,
user space should be able to rely on the guarantee that once it has
synchronously established a successful module unload, no more stale
artifacts associated with this module can be obtained subsequently.
Note that we must be careful to not invoke btf_free_id() in btf_put()
when btf_is_module() is true now. There could be a window where the
module unload drops a non-terminal reference, frees the IDR, but the
same ID gets reused and the second unconditional btf_free_id() ends up
releasing an unrelated entry.
To avoid a special case for btf_is_module() case, set btf->id to zero to
make btf_free_id() idempotent, such that we can unconditionally invoke it
from btf_put(), and also from the MODULE_STATE_GOING case. Since zero is
an invalid IDR, the idr_remove() should be a noop.
Note that we can be sure that by the time we reach final btf_put() for
btf_is_module() case, the btf_free_id() is already done, since the
module itself holds the BTF reference, and it will call this function
for the BTF before dropping its own reference.
[0]: https://lore.kernel.org/bpf/cover.1773170190.git.grbell@redhat.com
Fixes: 36e68442d1af ("bpf: Load and verify kernel module BTFs")
Acked-by: Martin KaFai Lau <martin.lau@kernel.org>
Suggested-by: Martin KaFai Lau <martin.lau@kernel.org>
Reported-by: Gregory Bell <grbell@redhat.com>
Reviewed-by: Emil Tsalapatis <emil@etsalapatis.com>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Link: https://lore.kernel.org/r/20260312205307.1346991-1-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 4b9ce671960627b2505b3f64742544ae9801df97 ]
Oliver reported that x86_pmu_del() ended up doing an out-of-bound memory access
when group_sched_in() fails and needs to roll back.
This *should* be handled by the transaction callbacks, but he found that when
the group leader is a software event, the transaction handlers of the wrong PMU
are used. Despite the move_group case in perf_event_open() and group_sched_in()
using pmu_ctx->pmu.
Turns out, inherit uses event->pmu to clone the events, effectively undoing the
move_group case for all inherited contexts. Fix this by also making inherit use
pmu_ctx->pmu, ensuring all inherited counters end up in the same pmu context.
Similarly, __perf_event_read() should use equally use pmu_ctx->pmu for the
group case.
Fixes: bd2756811766 ("perf: Rewrite core context handling")
Reported-by: Oliver Rosenberg <olrose55@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Ian Rogers <irogers@google.com>
Link: https://patch.msgid.link/20260309133713.GB606826@noisy.programming.kicks-ass.net
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 9a32bd9901fe5b1dcf544389dbf04f3b0a2fbab4 ]
The context time update code is repeated verbatim a few times.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Kan Liang <kan.liang@linux.intel.com>
Reviewed-by: Namhyung Kim <namhyung@kernel.org>
Link: https://lore.kernel.org/r/20240807115550.031212518@infradead.org
Stable-dep-of: 4b9ce6719606 ("perf: Make sure to use pmu_ctx->pmu for groups")
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit f4c31b07b136839e0fb3026f8a5b6543e3b14d2f ]
There are two special cases in the idle loop that are handled
inconsistently even though they are analogous.
The first one is when a cpuidle driver is absent and the default CPU
idle time power management implemented by the architecture code is used.
In that case, the scheduler tick is stopped every time before invoking
default_idle_call().
The second one is when a cpuidle driver is present, but there is only
one idle state in its table. In that case, the scheduler tick is never
stopped at all.
Since each of these approaches has its drawbacks, reconcile them with
the help of one simple heuristic. Namely, stop the tick if the CPU has
been woken up by it in the previous iteration of the idle loop, or let
it tick otherwise.
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Christian Loehle <christian.loehle@arm.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Reviewed-by: Qais Yousef <qyousef@layalina.io>
Reviewed-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
Fixes: ed98c3491998 ("sched: idle: Do not stop the tick before cpuidle_idle_call()")
[ rjw: Added Fixes tag, changelog edits ]
Link: https://patch.msgid.link/4741364.LvFx2qVVIh@rafael.j.wysocki
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 5ef268cb7a0aac55521fd9881f1939fa94a8988e ]
Remove unneeded warnings for handled errors from __arm_kprobe_ftrace()
because all caller handled the error correctly.
Link: https://lore.kernel.org/all/177261531182.1312989.8737778408503961141.stgit@mhiramat.tok.corp.google.com/
Reported-by: Zw Tang <shicenci@gmail.com>
Closes: https://lore.kernel.org/all/CAPHJ_V+J6YDb_wX2nhXU6kh466Dt_nyDSas-1i_Y8s7tqY-Mzw@mail.gmail.com/
Fixes: 9c89bb8e3272 ("kprobes: treewide: Cleanup the error messages for kprobes")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 5e5b8b49335971b68b54afeb0e7ded004945af07 ]
Remove unneeded gotos. Since the labels referred by these gotos have
only one reference for each, we can replace those gotos with the
referred code.
Link: https://lore.kernel.org/all/173371211203.480397.13988907319659165160.stgit@devnote2/
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Stable-dep-of: 5ef268cb7a0a ("kprobes: Remove unneeded warnings from __arm_kprobe_ftrace()")
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 98c88dc8a1ace642d9021b103b28cba7b51e3abc ]
Samuel and Alex reported regressions of the util_avg of RT rq with
commit 17e3e88ed0b6 ("sched/fair: Fix pelt lost idle time detection").
It happens that fair is updating and syncing the pelt clock with task one
when pick_next_task_fair() fails to pick a task but before the prev
scheduling class got a chance to update its pelt signals.
Move update_idle_rq_clock_pelt() in set_next_task_idle() which is called
after prev class has been called.
Fixes: 17e3e88ed0b6 ("sched/fair: Fix pelt lost idle time detection")
Reported-by: Samuel Wu <wusamuel@google.com>
Closes: https://lore.kernel.org/all/CAG2KctpO6VKS6GN4QWDji0t92_gNBJ7HjjXrE+6H+RwRXt=iLg@mail.gmail.com/
Reported-by: Alex Hoh <Alex.Hoh@mediatek.com>
Closes: https://lore.kernel.org/all/8cf19bf0e0054dcfed70e9935029201694f1bb5a.camel@mediatek.com/
Signed-off-by: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Samuel Wu <wusamuel@google.com>
Tested-by: Alex Hoh <Alex.Hoh@mediatek.com>
Link: https://patch.msgid.link/20260121163317.505635-1-vincent.guittot@linaro.org
(cherry picked from commit 98c88dc8a1ace642d9021b103b28cba7b51e3abc)
[ wusamuel: Did not include line 'exec_start = rq_clock_task()', which
is not present in 6.6.y but found in mainline ]
Signed-off-by: Samuel Wu <wusamuel@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 1bba3900ca18bdae28d1b9fa10f16a8f8cb2ada1 ]
In the preparation stage of CPU online, if the corresponding
the rdp's->nocb_cb_kthread does not exist, will be created,
there is a situation where the rdp's rcuop kthreads creation fails,
and then de-offload this CPU's rdp, does not assign this CPU's
rdp->nocb_cb_kthread pointer, but this rdp's->nocb_gp_rdp and
rdp's->rdp_gp->nocb_gp_kthread is still valid.
This will cause the subsequent re-offload operation of this offline
CPU, which will pass the conditional check and the kthread_unpark()
will access invalid rdp's->nocb_cb_kthread pointer.
This commit therefore use rdp's->nocb_gp_kthread instead of
rdp_gp's->nocb_gp_kthread for safety check.
Signed-off-by: Zqiang <qiang.zhang1211@gmail.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Signed-off-by: Neeraj Upadhyay (AMD) <neeraj.upadhyay@kernel.org>
[ Minor conflict resolved. ]
Signed-off-by: Jianqiang kang <jianqkang@sina.cn>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit d55c571e4333fac71826e8db3b9753fadfbead6a ]
This script
#!/usr/bin/bash
echo 0 > /proc/sys/kernel/randomize_va_space
echo 'void main(void) {}' > TEST.c
# -fcf-protection to ensure that the 1st endbr32 insn can't be emulated
gcc -m32 -fcf-protection=branch TEST.c -o test
bpftrace -e 'uprobe:./test:main {}' -c ./test
"hangs", the probed ./test task enters an endless loop.
The problem is that with randomize_va_space == 0
get_unmapped_area(TASK_SIZE - PAGE_SIZE) called by xol_add_vma() can not
just return the "addr == TASK_SIZE - PAGE_SIZE" hint, this addr is used
by the stack vma.
arch_get_unmapped_area_topdown() doesn't take TIF_ADDR32 into account and
in_32bit_syscall() is false, this leads to info.high_limit > TASK_SIZE.
vm_unmapped_area() happily returns the high address > TASK_SIZE and then
get_unmapped_area() returns -ENOMEM after the "if (addr > TASK_SIZE - len)"
check.
handle_swbp() doesn't report this failure (probably it should) and silently
restarts the probed insn. Endless loop.
I think that the right fix should change the x86 get_unmapped_area() paths
to rely on TIF_ADDR32 rather than in_32bit_syscall(). Note also that if
CONFIG_X86_X32_ABI=y, in_x32_syscall() falsely returns true in this case
because ->orig_ax = -1.
But we need a simple fix for -stable, so this patch just sets TS_COMPAT if
the probed task is 32-bit to make in_ia32_syscall() true.
Fixes: 1b028f784e8c ("x86/mm: Introduce mmap_compat_base() for 32-bit mmap()")
Reported-by: Paulo Andrade <pandrade@redhat.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lore.kernel.org/all/aV5uldEvV7pb4RA8@redhat.com/
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/aWO7Fdxn39piQnxu@redhat.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 6279846b9b2532e1b04559ef8bd0dec049f29383 upstream.
Syzbot reported a kernel warning due to a range invariant violation on
the following BPF program.
0: call bpf_get_netns_cookie
1: if r0 == 0 goto <exit>
2: if r0 & Oxffffffff goto <exit>
The issue is on the path where we fall through both jumps.
That path is unreachable at runtime: after insn 1, we know r0 != 0, but
with the sign extension on the jset, we would only fallthrough insn 2
if r0 == 0. Unfortunately, is_branch_taken() isn't currently able to
figure this out, so the verifier walks all branches. The verifier then
refines the register bounds using the second condition and we end
up with inconsistent bounds on this unreachable path:
1: if r0 == 0 goto <exit>
r0: u64=[0x1, 0xffffffffffffffff] var_off=(0, 0xffffffffffffffff)
2: if r0 & 0xffffffff goto <exit>
r0 before reg_bounds_sync: u64=[0x1, 0xffffffffffffffff] var_off=(0, 0)
r0 after reg_bounds_sync: u64=[0x1, 0] var_off=(0, 0)
Improving the range refinement for JSET to cover all cases is tricky. We
also don't expect many users to rely on JSET given LLVM doesn't generate
those instructions. So instead of improving the range refinement for
JSETs, Eduard suggested we forget the ranges whenever we're narrowing
tnums after a JSET. This patch implements that approach.
Reported-by: syzbot+c711ce17dd78e5d4fdcf@syzkaller.appspotmail.com
Suggested-by: Eduard Zingerman <eddyz87@gmail.com>
Acked-by: Yonghong Song <yonghong.song@linux.dev>
Acked-by: Eduard Zingerman <eddyz87@gmail.com>
Signed-off-by: Paul Chaignon <paul.chaignon@gmail.com>
Link: https://lore.kernel.org/r/9d4fd6432a095d281f815770608fdcd16028ce0b.1752171365.git.paul.chaignon@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
[ shung-hsi.yu: no detection or kernel warning for invariant violation before
6.8, but the same umin=1,umax=0 state can occur when jset is preceed by r0 < 1.
Changes were made to adapt to older range refinement logic before commit
67420501e868 ("bpf: generalize reg_set_min_max() to handle non-const register
comparisons"). ]
Signed-off-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 5f1ef0dfcb5b7f4a91a9b0e0ba533efd9f7e2cdb ]
A bug was reported about an infinite recursion caused by tracing the rcu
events with the kernel stack trace trigger enabled. The stack trace code
called back into RCU which then called the stack trace again.
Expand the ftrace recursion protection to add a set of bits to protect
events from recursion. Each bit represents the context that the event is
in (normal, softirq, interrupt and NMI).
Have the stack trace code use the interrupt context to protect against
recursion.
Note, the bug showed an issue in both the RCU code as well as the tracing
stacktrace code. This only handles the tracing stack trace side of the
bug. The RCU fix will be handled separately.
Link: https://lore.kernel.org/all/20260102122807.7025fc87@gandalf.local.home/
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Joel Fernandes <joel@joelfernandes.org>
Cc: "Paul E. McKenney" <paulmck@kernel.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Link: https://patch.msgid.link/20260105203141.515cd49f@gandalf.local.home
Reported-by: Yao Kai <yaokai34@huawei.com>
Tested-by: Yao Kai <yaokai34@huawei.com>
Fixes: 5f5fa7ea89dc ("rcu: Don't use negative nesting depth in __rcu_read_unlock()")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Leon Chen <leonchen.oss@139.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit d008ba8be8984760e36d7dcd4adbd5a41a645708 upstream.
Some of the sizing logic through tracer_alloc_buffers() uses int
internally, causing unexpected behavior if the user passes a value that
does not fit in an int (on my x86 machine, the result is uselessly tiny
buffers).
Fix by plumbing the parameter's real type (unsigned long) through to the
ring buffer allocation functions, which already use unsigned long.
It has always been possible to create larger ring buffers via the sysfs
interface: this only affects the cmdline parameter.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/bff42a4288aada08bdf74da3f5b67a2c28b761f8.1772852067.git.calvin@wbinvd.org
Fixes: 73c5162aa362 ("tracing: keep ring buffer to minimum size till used")
Signed-off-by: Calvin Owens <calvin@wbinvd.org>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 0a663b764dbdf135a126284f454c9f01f95a87d4 upstream.
When multiple syscall events are specified in the kernel command line
(e.g., trace_event=syscalls:sys_enter_openat,syscalls:sys_enter_close),
they are often not captured after boot, even though they appear enabled
in the tracing/set_event file.
The issue stems from how syscall events are initialized. Syscall
tracepoints require the global reference count (sys_tracepoint_refcount)
to transition from 0 to 1 to trigger the registration of the syscall
work (TIF_SYSCALL_TRACEPOINT) for tasks, including the init process (pid 1).
The current implementation of early_enable_events() with disable_first=true
used an interleaved sequence of "Disable A -> Enable A -> Disable B -> Enable B".
If multiple syscalls are enabled, the refcount never drops to zero,
preventing the 0->1 transition that triggers actual registration.
Fix this by splitting early_enable_events() into two distinct phases:
1. Disable all events specified in the buffer.
2. Enable all events specified in the buffer.
This ensures the refcount hits zero before re-enabling, allowing syscall
events to be properly activated during early boot.
The code is also refactored to use a helper function to avoid logic
duplication between the disable and enable phases.
Cc: stable@vger.kernel.org
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Link: https://patch.msgid.link/20260224023544.1250787-1-hehuiwen@kylinos.cn
Fixes: ce1039bd3a89 ("tracing: Fix enabling of syscall events on the command line")
Signed-off-by: Huiwen He <hehuiwen@kylinos.cn>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit 755a648e78f12574482d4698d877375793867fa1 ]
The trace_clock_jiffies() function that handles the "uptime" clock for
tracing calls jiffies_64_to_clock_t(). This causes the function tracer to
constantly recurse when the tracing clock is set to "uptime". Mark it
notrace to prevent unnecessary recursion when using the "uptime" clock.
Fixes: 58d4e21e50ff3 ("tracing: Fix wraparound problems in "uptime" trace clock")
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Link: https://patch.msgid.link/20260306212403.72270bb2@robin
Signed-off-by: Sasha Levin <sashal@kernel.org>
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commit e113f0b46d19626ec15388bcb91432c9a4fd6261 upstream.
After we hit ftrace is killed by some errors, the kernel crash if
we remove modules in which kprobe probes.
BUG: unable to handle page fault for address: fffffbfff805000d
PGD 817fcc067 P4D 817fcc067 PUD 817fc8067 PMD 101555067 PTE 0
Oops: Oops: 0000 [#1] SMP KASAN PTI
CPU: 4 UID: 0 PID: 2012 Comm: rmmod Tainted: G W OE
Tainted: [W]=WARN, [O]=OOT_MODULE, [E]=UNSIGNED_MODULE
RIP: 0010:kprobes_module_callback+0x89/0x790
RSP: 0018:ffff88812e157d30 EFLAGS: 00010a02
RAX: 1ffffffff805000d RBX: dffffc0000000000 RCX: ffffffff86a8de90
RDX: ffffed1025c2af9b RSI: 0000000000000008 RDI: ffffffffc0280068
RBP: 0000000000000000 R08: 0000000000000001 R09: ffffed1025c2af9a
R10: ffff88812e157cd7 R11: 205d323130325420 R12: 0000000000000002
R13: ffffffffc0290488 R14: 0000000000000002 R15: ffffffffc0280040
FS: 00007fbc450dd740(0000) GS:ffff888420331000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: fffffbfff805000d CR3: 000000010f624000 CR4: 00000000000006f0
Call Trace:
<TASK>
notifier_call_chain+0xc6/0x280
blocking_notifier_call_chain+0x60/0x90
__do_sys_delete_module.constprop.0+0x32a/0x4e0
do_syscall_64+0x5d/0xfa0
entry_SYSCALL_64_after_hwframe+0x76/0x7e
This is because the kprobe on ftrace does not correctly handles
the kprobe_ftrace_disabled flag set by ftrace_kill().
To prevent this error, check kprobe_ftrace_disabled in
__disarm_kprobe_ftrace() and skip all ftrace related operations.
Link: https://lore.kernel.org/all/176473947565.1727781.13110060700668331950.stgit@mhiramat.tok.corp.google.com/
Reported-by: Ye Bin <yebin10@huawei.com>
Closes: https://lore.kernel.org/all/20251125020536.2484381-1-yebin@huaweicloud.com/
Fixes: ae6aa16fdc16 ("kprobes: introduce ftrace based optimization")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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commit 5ee01f1a7343d6a3547b6802ca2d4cdce0edacb1 upstream.
When a task is migrated out of a css_set, cgroup_migrate_add_task()
first moves it from cset->tasks to cset->mg_tasks via:
list_move_tail(&task->cg_list, &cset->mg_tasks);
If a css_task_iter currently has it->task_pos pointing to this task,
css_set_move_task() calls css_task_iter_skip() to keep the iterator
valid. However, since the task has already been moved to ->mg_tasks,
the iterator is advanced relative to the mg_tasks list instead of the
original tasks list. As a result, remaining tasks on cset->tasks, as
well as tasks queued on cset->mg_tasks, can be skipped by iteration.
Fix this by calling css_set_skip_task_iters() before unlinking
task->cg_list from cset->tasks. This advances all active iterators to
the next task on cset->tasks, so iteration continues correctly even
when a task is concurrently being migrated.
This race is hard to hit in practice without instrumentation, but it
can be reproduced by artificially slowing down cgroup_procs_show().
For example, on an Android device a temporary
/sys/kernel/cgroup/cgroup_test knob can be added to inject a delay
into cgroup_procs_show(), and then:
1) Spawn three long-running tasks (PIDs 101, 102, 103).
2) Create a test cgroup and move the tasks into it.
3) Enable a large delay via /sys/kernel/cgroup/cgroup_test.
4) In one shell, read cgroup.procs from the test cgroup.
5) Within the delay window, in another shell migrate PID 102 by
writing it to a different cgroup.procs file.
Under this setup, cgroup.procs can intermittently show only PID 101
while skipping PID 103. Once the migration completes, reading the
file again shows all tasks as expected.
Note that this change does not allow removing the existing
css_set_skip_task_iters() call in css_set_move_task(). The new call
in cgroup_migrate_add_task() only handles iterators that are racing
with migration while the task is still on cset->tasks. Iterators may
also start after the task has been moved to cset->mg_tasks. If we
dropped css_set_skip_task_iters() from css_set_move_task(), such
iterators could keep task_pos pointing to a migrating task, causing
css_task_iter_advance() to malfunction on the destination css_set,
up to and including crashes or infinite loops.
The race window between migration and iteration is very small, and
css_task_iter is not on a hot path. In the worst case, when an
iterator is positioned on the first thread of the migrating process,
cgroup_migrate_add_task() may have to skip multiple tasks via
css_set_skip_task_iters(). However, this only happens when migration
and iteration actually race, so the performance impact is negligible
compared to the correctness fix provided here.
Fixes: b636fd38dc40 ("cgroup: Implement css_task_iter_skip()")
Cc: stable@vger.kernel.org # v5.2+
Signed-off-by: Qingye Zhao <zhaoqingye@honor.com>
Reviewed-by: Michal Koutný <mkoutny@suse.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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[ Upstream commit d557640e4ce589a24dca5ca7ce3b9680f471325f ]
If the cpuidle governor .select() callback is skipped because there
is only one idle state in the cpuidle driver, the .reflect() callback
should be skipped as well, at least for consistency (if not for
correctness), so do it.
Fixes: e5c9ffc6ae1b ("cpuidle: Skip governor when only one idle state is available")
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Reviewed-by: Christian Loehle <christian.loehle@arm.com>
Reviewed-by: Aboorva Devarajan <aboorvad@linux.ibm.com>
Reviewed-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://patch.msgid.link/12857700.O9o76ZdvQC@rafael.j.wysocki
Signed-off-by: Sasha Levin <sashal@kernel.org>
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[ Upstream commit 6c4b2243cb6c0755159bd567130d5e12e7b10d9f ]
There's an unpleasant corner case in unshare(2), when we have a
CLONE_NEWNS in flags and current->fs hadn't been shared at all; in that
case copy_mnt_ns() gets passed current->fs instead of a private copy,
which causes interesting warts in proof of correctness]
> I guess if private means fs->users == 1, the condition could still be true.
Unfortunately, it's worse than just a convoluted proof of correctness.
Consider the case when we have CLONE_NEWCGROUP in addition to CLONE_NEWNS
(and current->fs->users == 1).
We pass current->fs to copy_mnt_ns(), all right. Suppose it succeeds and
flips current->fs->{pwd,root} to corresponding locations in the new namespace.
Now we proceed to copy_cgroup_ns(), which fails (e.g. with -ENOMEM).
We call put_mnt_ns() on the namespace created by copy_mnt_ns(), it's
destroyed and its mount tree is dissolved, but... current->fs->root and
current->fs->pwd are both left pointing to now detached mounts.
They are pinning those, so it's not a UAF, but it leaves the calling
process with unshare(2) failing with -ENOMEM _and_ leaving it with
pwd and root on detached isolated mounts. The last part is clearly a bug.
There is other fun related to that mess (races with pivot_root(), including
the one between pivot_root() and fork(), of all things), but this one
is easy to isolate and fix - treat CLONE_NEWNS as "allocate a new
fs_struct even if it hadn't been shared in the first place". Sure, we could
go for something like "if both CLONE_NEWNS *and* one of the things that might
end up failing after copy_mnt_ns() call in create_new_namespaces() are set,
force allocation of new fs_struct", but let's keep it simple - the cost
of copy_fs_struct() is trivial.
Another benefit is that copy_mnt_ns() with CLONE_NEWNS *always* gets
a freshly allocated fs_struct, yet to be attached to anything. That
seriously simplifies the analysis...
FWIW, that bug had been there since the introduction of unshare(2) ;-/
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
Link: https://patch.msgid.link/20260207082524.GE3183987@ZenIV
Tested-by: Waiman Long <longman@redhat.com>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Signed-off-by: Sasha Levin <sashal@kernel.org>
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