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git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fix from Tejun Heo:
"This is a fix for a stall which triggers on ordered workqueues when
there are multiple inactive work items during workqueue property
changes through sysfs, which doesn't happen that frequently.
While really late, the fix is very low risk as it just repeats an
operation which is already being performed:
- Fix incomplete activation of multiple inactive works when
unplugging a pool_workqueue, where the pending_pwqs list
wasn't being updated for subsequent works"
* tag 'wq-for-7.0-rc7-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: Add pool_workqueue to pending_pwqs list when unplugging multiple inactive works
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fixes from Thomas Gleixner:
"Two fixes for the time/timers subsystem:
- Invert the inverted fastpath decision in check_tick_dependency(),
which prevents NOHZ full to stop the tick. That's a regression
introduced in the 7.0 merge window.
- Prevent a unpriviledged DoS in the clockevents code, where user
space can starve the timer interrupt by arming a timerfd or posix
interval timer in a tight loop with an absolute expiry time in the
past. The fix turned out to be incomplete and was was amended
yesterday to make it work on some 20 years old AMD machines as
well. All issues with it have been confirmed to be resolved by
various reporters"
* tag 'timers-urgent-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
clockevents: Prevent timer interrupt starvation
tick/nohz: Fix inverted return value in check_tick_dependency() fast path
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fix from Ingo Molnar:
"Fix DL server related slowdown to deferred fair tasks"
* tag 'sched-urgent-2026-04-12' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/deadline: Use revised wakeup rule for dl_server
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git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing probe fix from Masami Hiramatsu:
"Reject non-closed empty immediate strings
Fix a buffer index underflow bug that occurred when passing an
non-closed empty immediate string to the probe event"
* tag 'probes-fixes-v7.0-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing/probe: reject non-closed empty immediate strings
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git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux
Pull RISC-V updates from Paul Walmsley:
"Before v7.0 is released, fix a few issues with the CFI patchset,
merged earlier in v7.0-rc, that primarily affect interfaces to
non-kernel code:
- Improve the prctl() interface for per-task indirect branch landing
pad control to expand abbreviations and to resemble the speculation
control prctl() interface
- Expand the "LP" and "SS" abbreviations in the ptrace uapi header
file to "branch landing pad" and "shadow stack", to improve
readability
- Fix a typo in a CFI-related macro name in the ptrace uapi header
file
- Ensure that the indirect branch tracking state and shadow stack
state are unlocked immediately after an exec() on the new task so
that libc subsequently can control it
- While working in this area, clean up the kernel-internal,
cross-architecture prctl() function names by expanding the
abbreviations mentioned above"
* tag 'riscv-for-linus-v7.0-rc8' of git://git.kernel.org/pub/scm/linux/kernel/git/riscv/linux:
prctl: cfi: change the branch landing pad prctl()s to be more descriptive
riscv: ptrace: cfi: expand "SS" references to "shadow stack" in uapi headers
prctl: rename branch landing pad implementation functions to be more explicit
riscv: ptrace: expand "LP" references to "branch landing pads" in uapi headers
riscv: cfi: clear CFI lock status in start_thread()
riscv: ptrace: cfi: fix "PRACE" typo in uapi header
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Calvin reported an odd NMI watchdog lockup which claims that the CPU locked
up in user space. He provided a reproducer, which sets up a timerfd based
timer and then rearms it in a loop with an absolute expiry time of 1ns.
As the expiry time is in the past, the timer ends up as the first expiring
timer in the per CPU hrtimer base and the clockevent device is programmed
with the minimum delta value. If the machine is fast enough, this ends up
in a endless loop of programming the delta value to the minimum value
defined by the clock event device, before the timer interrupt can fire,
which starves the interrupt and consequently triggers the lockup detector
because the hrtimer callback of the lockup mechanism is never invoked.
As a first step to prevent this, avoid reprogramming the clock event device
when:
- a forced minimum delta event is pending
- the new expiry delta is less then or equal to the minimum delta
Thanks to Calvin for providing the reproducer and to Borislav for testing
and providing data from his Zen5 machine.
The problem is not limited to Zen5, but depending on the underlying
clock event device (e.g. TSC deadline timer on Intel) and the CPU speed
not necessarily observable.
This change serves only as the last resort and further changes will be made
to prevent this scenario earlier in the call chain as far as possible.
[ tglx: Updated to restore the old behaviour vs. !force and delta <= 0 and
fixed up the tick-broadcast handlers as pointed out by Borislav ]
Fixes: d316c57ff6bf ("[PATCH] clockevents: add core functionality")
Reported-by: Calvin Owens <calvin@wbinvd.org>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Tested-by: Calvin Owens <calvin@wbinvd.org>
Tested-by: Borislav Petkov <bp@alien8.de>
Link: https://lore.kernel.org/lkml/acMe-QZUel-bBYUh@mozart.vkv.me/
Link: https://patch.msgid.link/20260407083247.562657657@kernel.org
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git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux
Pull dma-mapping fix from Marek Szyprowski:
"A fix for DMA-mapping subsystem, which hides annoying, false-positive
warnings from DMA-API debug on coherent platforms like x86_64 (Mikhail
Gavrilov)"
* tag 'dma-mapping-7.0-2026-04-09' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux:
dma-debug: suppress cacheline overlap warning when arch has no DMA alignment requirement
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John noted that commit 115135422562 ("sched/deadline: Fix 'stuck' dl_server")
unfixed the issue from commit a3a70caf7906 ("sched/deadline: Fix dl_server
behaviour").
The issue in commit 115135422562 was for wakeups of the server after the
deadline; in which case you *have* to start a new period. The case for
a3a70caf7906 is wakeups before the deadline.
Now, because the server is effectively running a least-laxity policy, it means
that any wakeup during the runnable phase means dl_entity_overflow() will be
true. This means we need to adjust the runtime to allow it to still run until
the existing deadline expires.
Use the revised wakeup rule for dl_defer entities.
Fixes: 115135422562 ("sched/deadline: Fix 'stuck' dl_server")
Reported-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Acked-by: Juri Lelli <juri.lelli@redhat.com>
Tested-by: John Stultz <jstultz@google.com>
Link: https://patch.msgid.link/20260404102244.GB22575@noisy.programming.kicks-ass.net
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git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Pull misc fixes from Andrew Morton:
"Eight hotfixes. All are cc:stable and seven are for MM.
All are singletons - please see the changelogs for details"
* tag 'mm-hotfixes-stable-2026-04-06-15-27' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm:
ocfs2: fix out-of-bounds write in ocfs2_write_end_inline
mm/damon/stat: deallocate damon_call() failure leaking damon_ctx
mm/vma: fix memory leak in __mmap_region()
mm/memory_hotplug: maintain N_NORMAL_MEMORY during hotplug
mm/damon/sysfs: dealloc repeat_call_control if damon_call() fails
mm: reinstate unconditional writeback start in balance_dirty_pages()
liveupdate: propagate file deserialization failures
mm: filemap: fix nr_pages calculation overflow in filemap_map_pages()
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Commit 56534673cea7f ("tick/nohz: Optimize check_tick_dependency() with
early return") added a fast path that returns !val when the tick_stop
tracepoint is disabled.
This is inverted: the slow path returns true when a dependency IS found
(val != 0), but !val returns true when val is zero (no dependency). The
result is that can_stop_full_tick() sees "dependency found" when there are
none, and the tick never stops on nohz_full CPUs.
Fix this by returning !!val instead of !val, matching the slow-path semantics.
Fixes: 56534673cea7f ("tick/nohz: Optimize check_tick_dependency() with early return")
Signed-off-by: Josh Snyder <josh@code406.com>
Signed-off-by: Thomas Gleixner <tglx@kernel.org>
Assisted-by: Claude:claude-opus-4-6
Link: https://patch.msgid.link/20260402-fix-idle-tick2-v1-1-eecb589649d3@code406.com
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luo_session_deserialize() ignored the return value from
luo_file_deserialize(). As a result, a session could be left partially
restored even though the /dev/liveupdate open path treats deserialization
failures as fatal.
Propagate the error so a failed file deserialization aborts session
deserialization instead of silently continuing.
Link: https://lkml.kernel.org/r/20260325044608.8407-1-leotimmins1974@gmail.com
Link: https://lkml.kernel.org/r/20260325044608.8407-2-leotimmins1974@gmail.com
Fixes: 16cec0d26521 ("liveupdate: luo_session: add ioctls for file preservation")
Signed-off-by: Leo Timmins <leotimmins1974@gmail.com>
Reviewed-by: Pasha Tatashin <pasha.tatashin@soleen.com>
Reviewed-by: Pratyush Yadav <pratyush@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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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>
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull scheduler fixes from Ingo Molnar:
- Fix zero_vruntime tracking again (Peter Zijlstra)
- Fix avg_vruntime() usage in sched_debug (Peter Zijlstra)
* tag 'sched-urgent-2026-04-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
sched/debug: Fix avg_vruntime() usage
sched/fair: Fix zero_vruntime tracking fix
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Per Linus' comments requesting the replacement of "INDIR_BR_LP" in the
indirect branch tracking prctl()s with something more readable, and
suggesting the use of the speculation control prctl()s as an exemplar,
reimplement the prctl()s and related constants that control per-task
forward-edge control flow integrity.
This primarily involves two changes. First, the prctls are
restructured to resemble the style of the speculative execution
workaround control prctls PR_{GET,SET}_SPECULATION_CTRL, to make them
easier to extend in the future. Second, the "indir_br_lp" abbrevation
is expanded to "branch_landing_pads" to be less telegraphic. The
kselftest and documentation is adjusted accordingly.
Link: https://lore.kernel.org/linux-riscv/CAHk-=whhSLGZAx3N5jJpb4GLFDqH_QvS07D+6BnkPWmCEzTAgw@mail.gmail.com/
Cc: Deepak Gupta <debug@rivosinc.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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Per Linus' comments about the unreadability of abbreviations such as
"indir_br_lp", rename the three prctl() implementation functions to be more
explicit. This involves renaming "indir_br_lp_status" in the function
names to "branch_landing_pad_state".
While here, add _prctl_ into the function names, following the
speculation control prctl implementation functions.
Link: https://lore.kernel.org/linux-riscv/CAHk-=whhSLGZAx3N5jJpb4GLFDqH_QvS07D+6BnkPWmCEzTAgw@mail.gmail.com/
Cc: Deepak Gupta <debug@rivosinc.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mark Brown <broonie@kernel.org>
Signed-off-by: Paul Walmsley <pjw@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext
Pull sched_ext fixes from Tejun Heo:
"These are late but both fix subtle yet critical problems and the blast
radius is limited strictly to sched_ext.
- Fix stale direct dispatch state in ddsp_dsq_id which can cause
spurious warnings in mark_direct_dispatch() on task wakeup
- Fix is_bpf_migration_disabled() false negative on non-PREEMPT_RCU
configs which can lead to incorrectly dispatching migration-
disabled tasks to remote CPUs"
* tag 'sched_ext-for-7.0-rc6-fixes-2' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
sched_ext: Fix stale direct dispatch state in ddsp_dsq_id
sched_ext: Fix is_bpf_migration_disabled() false negative on non-PREEMPT_RCU
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@p->scx.ddsp_dsq_id can be left set (non-SCX_DSQ_INVALID) triggering a
spurious warning in mark_direct_dispatch() when the next wakeup's
ops.select_cpu() calls scx_bpf_dsq_insert(), such as:
WARNING: kernel/sched/ext.c:1273 at scx_dsq_insert_commit+0xcd/0x140
The root cause is that ddsp_dsq_id was only cleared in dispatch_enqueue(),
which is not reached in all paths that consume or cancel a direct dispatch
verdict.
Fix it by clearing it at the right places:
- direct_dispatch(): cache the direct dispatch state in local variables
and clear it before dispatch_enqueue() on the synchronous path. For
the deferred path, the direct dispatch state must remain set until
process_ddsp_deferred_locals() consumes them.
- process_ddsp_deferred_locals(): cache the dispatch state in local
variables and clear it before calling dispatch_to_local_dsq(), which
may migrate the task to another rq.
- do_enqueue_task(): clear the dispatch state on the enqueue path
(local/global/bypass fallbacks), where the direct dispatch verdict is
ignored.
- dequeue_task_scx(): clear the dispatch state after dispatch_dequeue()
to handle both the deferred dispatch cancellation and the holding_cpu
race, covering all cases where a pending direct dispatch is
cancelled.
- scx_disable_task(): clear the direct dispatch state when
transitioning a task out of the current scheduler. Waking tasks may
have had the direct dispatch state set by the outgoing scheduler's
ops.select_cpu() and then been queued on a wake_list via
ttwu_queue_wakelist(), when SCX_OPS_ALLOW_QUEUED_WAKEUP is set. Such
tasks are not on the runqueue and are not iterated by scx_bypass(),
so their direct dispatch state won't be cleared. Without this clear,
any subsequent SCX scheduler that tries to direct dispatch the task
will trigger the WARN_ON_ONCE() in mark_direct_dispatch().
Fixes: 5b26f7b920f7 ("sched_ext: Allow SCX_DSQ_LOCAL_ON for direct dispatches")
Cc: stable@vger.kernel.org # v6.12+
Cc: Daniel Hodges <hodgesd@meta.com>
Cc: Patrick Somaru <patsomaru@meta.com>
Signed-off-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"These fix a potential NULL pointer dereference in the energy model
netlink interface and a potential double free in an error path in
the common cpufreq governor management code:
- Fix a NULL pointer dereference in the energy model netlink
interface that may occur if a given perf domain ID is not
recognized (Changwoo Min)
- Avoid double free in the cpufreq_dbs_governor_init() error
path when kobject_init_and_add() fails (Guangshuo Li)"
* tag 'pm-7.0-rc7' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
cpufreq: governor: fix double free in cpufreq_dbs_governor_init() error path
PM: EM: Fix NULL pointer dereference when perf domain ID is not found
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Pull bpf fixes from Alexei Starovoitov:
- Fix register equivalence for pointers to packet (Alexei Starovoitov)
- Fix incorrect pruning due to atomic fetch precision tracking (Daniel
Borkmann)
- Fix grace period wait for bpf_link-ed tracepoints (Kumar Kartikeya
Dwivedi)
- Fix use-after-free of sockmap's sk->sk_socket (Kuniyuki Iwashima)
- Reject direct access to nullable PTR_TO_BUF pointers (Qi Tang)
- Reject sleepable kprobe_multi programs at attach time (Varun R
Mallya)
* tag 'bpf-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/bpf/bpf:
selftests/bpf: Add more precision tracking tests for atomics
bpf: Fix incorrect pruning due to atomic fetch precision tracking
bpf: Reject sleepable kprobe_multi programs at attach time
bpf: reject direct access to nullable PTR_TO_BUF pointers
bpf: sockmap: Fix use-after-free of sk->sk_socket in sk_psock_verdict_data_ready().
bpf: Fix grace period wait for tracepoint bpf_link
bpf: Fix regsafe() for pointers to packet
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Since commit 8e4f0b1ebcf2 ("bpf: use rcu_read_lock_dont_migrate() for
trampoline.c"), the BPF prolog (__bpf_prog_enter) calls migrate_disable()
only when CONFIG_PREEMPT_RCU is enabled, via rcu_read_lock_dont_migrate().
Without CONFIG_PREEMPT_RCU, the prolog never touches migration_disabled,
so migration_disabled == 1 always means the task is truly
migration-disabled regardless of whether it is the current task.
The old unconditional p == current check was a false negative in this
case, potentially allowing a migration-disabled task to be dispatched to
a remote CPU and triggering scx_error in task_can_run_on_remote_rq().
Only apply the p == current disambiguation when CONFIG_PREEMPT_RCU is
enabled, where the ambiguity with the BPF prolog still exists.
Fixes: 8e4f0b1ebcf2 ("bpf: use rcu_read_lock_dont_migrate() for trampoline.c")
Cc: stable@vger.kernel.org # v6.18+
Link: https://lore.kernel.org/lkml/20250821090609.42508-8-dongml2@chinatelecom.cn/
Signed-off-by: Changwoo Min <changwoo@igalia.com>
Reviewed-by: Andrea Righi <arighi@nvidia.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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When backtrack_insn encounters a BPF_STX instruction with BPF_ATOMIC
and BPF_FETCH, the src register (or r0 for BPF_CMPXCHG) also acts as
a destination, thus receiving the old value from the memory location.
The current backtracking logic does not account for this. It treats
atomic fetch operations the same as regular stores where the src
register is only an input. This leads the backtrack_insn to fail to
propagate precision to the stack location, which is then not marked
as precise!
Later, the verifier's path pruning can incorrectly consider two states
equivalent when they differ in terms of stack state. Meaning, two
branches can be treated as equivalent and thus get pruned when they
should not be seen as such.
Fix it as follows: Extend the BPF_LDX handling in backtrack_insn to
also cover atomic fetch operations via is_atomic_fetch_insn() helper.
When the fetch dst register is being tracked for precision, clear it,
and propagate precision over to the stack slot. For non-stack memory,
the precision walk stops at the atomic instruction, same as regular
BPF_LDX. This covers all fetch variants.
Before:
0: (b7) r1 = 8 ; R1=8
1: (7b) *(u64 *)(r10 -8) = r1 ; R1=8 R10=fp0 fp-8=8
2: (b7) r2 = 0 ; R2=0
3: (db) r2 = atomic64_fetch_add((u64 *)(r10 -8), r2) ; R2=8 R10=fp0 fp-8=mmmmmmmm
4: (bf) r3 = r10 ; R3=fp0 R10=fp0
5: (0f) r3 += r2
mark_precise: frame0: last_idx 5 first_idx 0 subseq_idx -1
mark_precise: frame0: regs=r2 stack= before 4: (bf) r3 = r10
mark_precise: frame0: regs=r2 stack= before 3: (db) r2 = atomic64_fetch_add((u64 *)(r10 -8), r2)
mark_precise: frame0: regs=r2 stack= before 2: (b7) r2 = 0
6: R2=8 R3=fp8
6: (b7) r0 = 0 ; R0=0
7: (95) exit
After:
0: (b7) r1 = 8 ; R1=8
1: (7b) *(u64 *)(r10 -8) = r1 ; R1=8 R10=fp0 fp-8=8
2: (b7) r2 = 0 ; R2=0
3: (db) r2 = atomic64_fetch_add((u64 *)(r10 -8), r2) ; R2=8 R10=fp0 fp-8=mmmmmmmm
4: (bf) r3 = r10 ; R3=fp0 R10=fp0
5: (0f) r3 += r2
mark_precise: frame0: last_idx 5 first_idx 0 subseq_idx -1
mark_precise: frame0: regs=r2 stack= before 4: (bf) r3 = r10
mark_precise: frame0: regs=r2 stack= before 3: (db) r2 = atomic64_fetch_add((u64 *)(r10 -8), r2)
mark_precise: frame0: regs= stack=-8 before 2: (b7) r2 = 0
mark_precise: frame0: regs= stack=-8 before 1: (7b) *(u64 *)(r10 -8) = r1
mark_precise: frame0: regs=r1 stack= before 0: (b7) r1 = 8
6: R2=8 R3=fp8
6: (b7) r0 = 0 ; R0=0
7: (95) exit
Fixes: 5ffa25502b5a ("bpf: Add instructions for atomic_[cmp]xchg")
Fixes: 5ca419f2864a ("bpf: Add BPF_FETCH field / create atomic_fetch_add instruction")
Reported-by: STAR Labs SG <info@starlabs.sg>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/r/20260331222020.401848-1-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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kprobe.multi programs run in atomic/RCU context and cannot sleep.
However, bpf_kprobe_multi_link_attach() did not validate whether the
program being attached had the sleepable flag set, allowing sleepable
helpers such as bpf_copy_from_user() to be invoked from a non-sleepable
context.
This causes a "sleeping function called from invalid context" splat:
BUG: sleeping function called from invalid context at ./include/linux/uaccess.h:169
in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 1787, name: sudo
preempt_count: 1, expected: 0
RCU nest depth: 2, expected: 0
Fix this by rejecting sleepable programs early in
bpf_kprobe_multi_link_attach(), before any further processing.
Fixes: 0dcac2725406 ("bpf: Add multi kprobe link")
Signed-off-by: Varun R Mallya <varunrmallya@gmail.com>
Acked-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Leon Hwang <leon.hwang@linux.dev>
Acked-by: Jiri Olsa <jolsa@kernel.org>
Link: https://lore.kernel.org/r/20260401191126.440683-1-varunrmallya@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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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>
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John reported that stress-ng-yield could make his machine unhappy and
managed to bisect it to commit b3d99f43c72b ("sched/fair: Fix
zero_vruntime tracking").
The commit in question changes avg_vruntime() from a function that is
a pure reader, to a function that updates variables. This turns an
unlocked sched/debug usage of this function from a minor mistake into
a data corruptor.
Fixes: af4cf40470c2 ("sched/fair: Add cfs_rq::avg_vruntime")
Fixes: b3d99f43c72b ("sched/fair: Fix zero_vruntime tracking")
Reported-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Tested-by: John Stultz <jstultz@google.com>
Link: https://patch.msgid.link/20260401132355.196370805@infradead.org
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John reported that stress-ng-yield could make his machine unhappy and
managed to bisect it to commit b3d99f43c72b ("sched/fair: Fix
zero_vruntime tracking").
The combination of yield and that commit was specific enough to
hypothesize the following scenario:
Suppose we have 2 runnable tasks, both doing yield. Then one will be
eligible and one will not be, because the average position must be in
between these two entities.
Therefore, the runnable task will be eligible, and be promoted a full
slice (all the tasks do is yield after all). This causes it to jump over
the other task and now the other task is eligible and current is no
longer. So we schedule.
Since we are runnable, there is no {de,en}queue. All we have is the
__{en,de}queue_entity() from {put_prev,set_next}_task(). But per the
fingered commit, those two no longer move zero_vruntime.
All that moves zero_vruntime are tick and full {de,en}queue.
This means, that if the two tasks playing leapfrog can reach the
critical speed to reach the overflow point inside one tick's worth of
time, we're up a creek.
Additionally, when multiple cgroups are involved, there is no guarantee
the tick will in fact hit every cgroup in a timely manner. Statistically
speaking it will, but that same statistics does not rule out the
possibility of one cgroup not getting a tick for a significant amount of
time -- however unlikely.
Therefore, just like with the yield() case, force an update at the end
of every slice. This ensures the update is never more than a single
slice behind and the whole thing is within 2 lag bounds as per the
comment on entity_key().
Fixes: b3d99f43c72b ("sched/fair: Fix zero_vruntime tracking")
Reported-by: John Stultz <jstultz@google.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Vincent Guittot <vincent.guittot@linaro.org>
Tested-by: K Prateek Nayak <kprateek.nayak@amd.com>
Tested-by: John Stultz <jstultz@google.com>
Link: https://patch.msgid.link/20260401132355.081530332@infradead.org
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inactive works
In unplug_oldest_pwq(), the first inactive work item on the
pool_workqueue is activated correctly. However, if multiple inactive
works exist on the same pool_workqueue, subsequent works fail to
activate because wq_node_nr_active.pending_pwqs is empty — the list
insertion is skipped when the pool_workqueue is plugged.
Fix this by checking for additional inactive works in
unplug_oldest_pwq() and updating wq_node_nr_active.pending_pwqs
accordingly.
Fixes: 4c065dbce1e8 ("workqueue: Enable unbound cpumask update on ordered workqueues")
Cc: stable@vger.kernel.org
Cc: Carlos Santa <carlos.santa@intel.com>
Cc: Ryan Neph <ryanneph@google.com>
Cc: Lai Jiangshan <jiangshanlai@gmail.com>
Cc: Waiman Long <longman@redhat.com>
Cc: linux-kernel@vger.kernel.org
Signed-off-by: Matthew Brost <matthew.brost@intel.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Waiman Long <longman@redhat.com>
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Recently, tracepoints were switched from using disabled preemption
(which acts as RCU read section) to SRCU-fast when they are not
faultable. This means that to do a proper grace period wait for programs
running in such tracepoints, we must use SRCU's grace period wait.
This is only for non-faultable tracepoints, faultable ones continue
using RCU Tasks Trace.
However, bpf_link_free() currently does call_rcu() for all cases when
the link is non-sleepable (hence, for tracepoints, non-faultable). Fix
this by doing a call_srcu() grace period wait.
As far RCU Tasks Trace gp -> RCU gp chaining is concerned, it is deemed
unnecessary for tracepoint programs. The link and program are either
accessed under RCU Tasks Trace protection, or SRCU-fast protection now.
The earlier logic of chaining both RCU Tasks Trace and RCU gp waits was
to generalize the logic, even if it conceded an extra RCU gp wait,
however that is unnecessary for tracepoints even before this change.
In practice no cost was paid since rcu_trace_implies_rcu_gp() was always
true. Hence we need not chaining any RCU gp after the SRCU gp.
For instance, in the non-faultable raw tracepoint, the RCU read section
of the program in __bpf_trace_run() is enclosed in the SRCU gp, likewise
for faultable raw tracepoint, the program is under the RCU Tasks Trace
protection. Hence, the outermost scope can be waited upon to ensure
correctness.
Also, sleepable programs cannot be attached to non-faultable
tracepoints, so whenever program or link is sleepable, only RCU Tasks
Trace protection is being used for the link and prog.
Fixes: a46023d5616e ("tracing: Guard __DECLARE_TRACE() use of __DO_TRACE_CALL() with SRCU-fast")
Reviewed-by: Sun Jian <sun.jian.kdev@gmail.com>
Reviewed-by: Puranjay Mohan <puranjay@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Acked-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Link: https://lore.kernel.org/r/20260331211021.1632902-2-memxor@gmail.com
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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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
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext
Pull sched_ext fixes from Tejun Heo:
- Fix SCX_KICK_WAIT deadlock where multiple CPUs waiting for each other
in hardirq context form a cycle. Move the wait to a balance callback
which can drop the rq lock and process IPIs.
- Fix inconsistent NUMA node lookup in scx_select_cpu_dfl() where
the waker_node used cpu_to_node() while prev_cpu used
scx_cpu_node_if_enabled(), leading to undefined behavior when
per-node idle tracking is disabled.
* tag 'sched_ext-for-7.0-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/sched_ext:
selftests/sched_ext: Add cyclic SCX_KICK_WAIT stress test
sched_ext: Fix SCX_KICK_WAIT deadlock by deferring wait to balance callback
sched_ext: Fix inconsistent NUMA node lookup in scx_select_cpu_dfl()
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq
Pull workqueue fix from Tejun Heo:
- Fix false positive stall reports on weakly ordered architectures
where the lockless worklist/timestamp check in the watchdog can
observe stale values due to memory reordering.
Recheck under pool->lock to confirm.
* tag 'wq-for-7.0-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/wq:
workqueue: Better describe stall check
workqueue: Fix false positive stall reports
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git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup
Pull cgroup fixes from Tejun Heo:
- Fix cgroup rmdir racing with dying tasks.
Deferred task cgroup unlink introduced a window where cgroup.procs
is empty but the cgroup is still populated, causing rmdir to fail
with -EBUSY and selftest failures.
Make rmdir wait for dying tasks to fully leave and fix selftests to
not depend on synchronous populated updates.
- Fix cpuset v1 task migration failure from empty cpusets under strict
security policies.
When CPU hotplug removes the last CPU from a v1 cpuset, tasks must be
migrated to an ancestor without a security_task_setscheduler() check
that would block the migration.
* tag 'cgroup-for-7.0-rc6-fixes' of git://git.kernel.org/pub/scm/linux/kernel/git/tj/cgroup:
cgroup/cpuset: Skip security check for hotplug induced v1 task migration
cgroup/cpuset: Simplify setsched decision check in task iteration loop of cpuset_can_attach()
cgroup: Fix cgroup_drain_dying() testing the wrong condition
selftests/cgroup: Don't require synchronous populated update on task exit
cgroup: Wait for dying tasks to leave on rmdir
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When a CPU hot removal causes a v1 cpuset to lose all its CPUs, the
cpuset hotplug handler will schedule a work function to migrate tasks
in that cpuset with no CPU to its ancestor to enable those tasks to
continue running.
If a strict security policy is in place, however, the task migration
may fail when security_task_setscheduler() call in cpuset_can_attach()
returns a -EACCES error. That will mean that those tasks will have
no CPU to run on. The system administrators will have to explicitly
intervene to either add CPUs to that cpuset or move the tasks elsewhere
if they are aware of it.
This problem was found by a reported test failure in the LTP's
cpuset_hotplug_test.sh. Fix this problem by treating this special case as
an exception to skip the setsched security check in cpuset_can_attach()
when a v1 cpuset with tasks have no CPU left.
With that patch applied, the cpuset_hotplug_test.sh test can be run
successfully without failure.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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cpuset_can_attach()
Centralize the check required to run security_task_setscheduler() in
the task iteration loop of cpuset_can_attach() outside of the loop as
it has no dependency on the characteristics of the tasks themselves.
There is no functional change.
Signed-off-by: Waiman Long <longman@redhat.com>
Signed-off-by: Tejun Heo <tj@kernel.org>
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|
dev_energymodel_nl_get_perf_domains_doit() calls
em_perf_domain_get_by_id() but does not check the return value before
passing it to __em_nl_get_pd_size(). When a caller supplies a
non-existent perf domain ID, em_perf_domain_get_by_id() returns NULL,
and __em_nl_get_pd_size() immediately dereferences pd->cpus
(struct offset 0x30), causing a NULL pointer dereference.
The sister handler dev_energymodel_nl_get_perf_table_doit() already
handles this correctly via __em_nl_get_pd_table_id(), which returns
NULL and causes the caller to return -EINVAL. Add the same NULL check
in the get-perf-domains do handler.
Fixes: 380ff27af25e ("PM: EM: Add dump to get-perf-domains in the EM YNL spec")
Reported-by: Yi Lai <yi1.lai@linux.intel.com>
Closes: https://lore.kernel.org/lkml/aXiySM79UYfk+ytd@ly-workstation/
Signed-off-by: Changwoo Min <changwoo@igalia.com>
Cc: 6.19+ <stable@vger.kernel.org> # 6.19+
[ rjw: Subject and changelog edits ]
Link: https://patch.msgid.link/20260329073615.649976-1-changwoo@igalia.com
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
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|
SCX_KICK_WAIT busy-waits in kick_cpus_irq_workfn() using
smp_cond_load_acquire() until the target CPU's kick_sync advances. Because
the irq_work runs in hardirq context, the waiting CPU cannot reschedule and
its own kick_sync never advances. If multiple CPUs form a wait cycle, all
CPUs deadlock.
Replace the busy-wait in kick_cpus_irq_workfn() with resched_curr() to
force the CPU through do_pick_task_scx(), which queues a balance callback
to perform the wait. The balance callback drops the rq lock and enables
IRQs following the sched_core_balance() pattern, so the CPU can process
IPIs while waiting. The local CPU's kick_sync is advanced on entry to
do_pick_task_scx() and continuously during the wait, ensuring any CPU that
starts waiting for us sees the advancement and cannot form cyclic
dependencies.
Fixes: 90e55164dad4 ("sched_ext: Implement SCX_KICK_WAIT")
Cc: stable@vger.kernel.org # v6.12+
Reported-by: Christian Loehle <christian.loehle@arm.com>
Link: https://lore.kernel.org/r/20260316100249.1651641-1-christian.loehle@arm.com
Signed-off-by: Tejun Heo <tj@kernel.org>
Tested-by: Christian Loehle <christian.loehle@arm.com>
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|
requirement
When CONFIG_DMA_API_DEBUG is enabled, the DMA debug infrastructure
tracks active mappings per cacheline and warns if two different DMA
mappings share the same cacheline ("cacheline tracking EEXIST,
overlapping mappings aren't supported").
On x86_64, ARCH_KMALLOC_MINALIGN defaults to 8, so small kmalloc
allocations (e.g. the 8-byte hub->buffer and hub->status in the USB
hub driver) frequently land in the same 64-byte cacheline. When both
are DMA-mapped, this triggers a false positive warning.
This has been reported repeatedly since v5.14 (when the EEXIST check
was added) across various USB host controllers and devices including
xhci_hcd with USB hubs, USB audio devices, and USB ethernet adapters.
The cacheline overlap is only a real concern on architectures that
require DMA buffer alignment to cacheline boundaries (i.e. where
ARCH_DMA_MINALIGN >= L1_CACHE_BYTES). On architectures like x86_64
where dma_get_cache_alignment() returns 1, the hardware is
cache-coherent and overlapping cacheline mappings are harmless.
Suppress the EEXIST warning when dma_get_cache_alignment() is less
than L1_CACHE_BYTES, indicating the architecture does not require
cacheline-aligned DMA buffers.
Verified with a kernel module reproducer that performs two kmalloc(8)
allocations back-to-back and DMA-maps both:
Before: allocations share a cacheline, EEXIST fires within ~50 pairs
After: same cacheline pair found, but no warning emitted
Fixes: 2b4bbc6231d7 ("dma-debug: report -EEXIST errors in add_dma_entry")
Link: https://bugzilla.kernel.org/show_bug.cgi?id=215740
Suggested-by: Harry Yoo <harry@kernel.org>
Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Signed-off-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Link: https://lore.kernel.org/r/20260327124156.24820-1-mikhail.v.gavrilov@gmail.com
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull timer fix from Ingo Molnar:
"Fix an argument order bug in the alarm timer forwarding logic, which
may cause missed expirations or incorrect overrun accounting"
* tag 'timers-urgent-2026-03-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
alarmtimer: Fix argument order in alarm_timer_forward()
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git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull futex fixes from Ingo Molnar:
- Tighten up the sys_futex_requeue() ABI a bit, to disallow dissimilar
futex flags and potential UaF access (Peter Zijlstra)
- Fix UaF between futex_key_to_node_opt() and vma_replace_policy()
(Hao-Yu Yang)
- Clear stale exiting pointer in futex_lock_pi() retry path, which
triggered a warning (and potential misbehavior) in stress-testing
(Davidlohr Bueso)
* tag 'locking-urgent-2026-03-29' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
futex: Clear stale exiting pointer in futex_lock_pi() retry path
futex: Fix UaF between futex_key_to_node_opt() and vma_replace_policy()
futex: Require sys_futex_requeue() to have identical flags
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git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace
Pull tracing fixes from Steven Rostedt:
- Fix potential deadlock in osnoise and hotplug
The interface_lock can be called by a osnoise thread and the CPU
shutdown logic of osnoise can wait for this thread to finish. But
cpus_read_lock() can also be taken while holding the interface_lock.
This produces a circular lock dependency and can cause a deadlock.
Swap the ordering of cpus_read_lock() and the interface_lock to have
interface_lock taken within the cpus_read_lock() context to prevent
this circular dependency.
- Fix freeing of event triggers in early boot up
If the same trigger is added on the kernel command line, the second
one will fail to be applied and the trigger created will be freed.
This calls into the deferred logic and creates a kernel thread to do
the freeing. But the command line logic is called before kernel
threads can be created and this leads to a NULL pointer dereference.
Delay freeing event triggers until late init.
* tag 'trace-v7.0-rc5' of git://git.kernel.org/pub/scm/linux/kernel/git/trace/linux-trace:
tracing: Drain deferred trigger frees if kthread creation fails
tracing: Fix potential deadlock in cpu hotplug with osnoise
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|
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
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Boot-time trigger registration can fail before the trigger-data cleanup
kthread exists. Deferring those frees until late init is fine, but the
post-boot fallback must still drain the deferred list if kthread
creation never succeeds.
Otherwise, boot-deferred nodes can accumulate on
trigger_data_free_list, later frees fall back to synchronously freeing
only the current object, and the older queued entries are leaked
forever.
To trigger this, add the following to the kernel command line:
trace_event=sched_switch trace_trigger=sched_switch.traceon,sched_switch.traceon
The second traceon trigger will fail and be freed. This triggers a NULL
pointer dereference and crashes the kernel.
Keep the deferred boot-time behavior, but when kthread creation fails,
drain the whole queued list synchronously. Do the same in the late-init
drain path so queued entries are not stranded there either.
Cc: stable@vger.kernel.org
Link: https://patch.msgid.link/20260324221326.1395799-3-atwellwea@gmail.com
Fixes: 61d445af0a7c ("tracing: Add bulk garbage collection of freeing event_trigger_data")
Signed-off-by: Wesley Atwell <atwellwea@gmail.com>
Signed-off-by: Steven Rostedt (Google) <rostedt@goodmis.org>
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git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl
Pull sysctl fix from Joel Granados:
"Fix uninitialized variable error when writing to a sysctl bitmap
Removed the possibility of returning an unjustified -EINVAL when
writing to a sysctl bitmap"
* tag 'sysctl-7.00-fixes-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/sysctl/sysctl:
sysctl: fix uninitialized variable in proc_do_large_bitmap
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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>
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git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm
Pull power management fixes from Rafael Wysocki:
"These fix two cpufreq issues, one in the core and one in the
conservative governor, and two issues related to system sleep:
- Restore the cpufreq core behavior changed inadvertently during the
6.19 development cycle to call cpufreq_frequency_table_cpuinfo()
for cpufreq policies getting re-initialized which ensures that
policy->max and policy->cpuinfo_max_freq will be valid going
forward (Viresh Kumar)
- Adjust the cached requested frequency in the conservative cpufreq
governor on policy limits changes to prevent it from becoming stale
in some cases (Viresh Kumar)
- Prevent pm_restore_gfp_mask() from triggering a WARN_ON() in some
code paths in which it is legitimately called without invoking
pm_restrict_gfp_mask() previously (Youngjun Park)
- Update snapshot_write_finalize() to take trailing zero pages into
account properly which prevents user space restore from failing
subsequently in some cases (Alberto Garcia)"
* tag 'pm-7.0-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/rafael/linux-pm:
PM: sleep: Drop spurious WARN_ON() from pm_restore_gfp_mask()
PM: hibernate: Drain trailing zero pages on userspace restore
cpufreq: conservative: Reset requested_freq on limits change
cpufreq: Don't skip cpufreq_frequency_table_cpuinfo()
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|
git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux
Pull dma-mapping fixes from Marek Szyprowski:
"A set of fixes for DMA-mapping subsystem, which resolve false-
positive warnings from KMSAN and DMA-API debug (Shigeru Yoshida
and Leon Romanovsky) as well as a simple build fix (Miguel Ojeda)"
* tag 'dma-mapping-7.0-2026-03-25' of git://git.kernel.org/pub/scm/linux/kernel/git/mszyprowski/linux:
dma-mapping: add missing `inline` for `dma_free_attrs`
mm/hmm: Indicate that HMM requires DMA coherency
RDMA/umem: Tell DMA mapping that UMEM requires coherency
iommu/dma: add support for DMA_ATTR_REQUIRE_COHERENT attribute
dma-direct: prevent SWIOTLB path when DMA_ATTR_REQUIRE_COHERENT is set
dma-mapping: Introduce DMA require coherency attribute
dma-mapping: Clarify valid conditions for CPU cache line overlap
dma-mapping: handle DMA_ATTR_CPU_CACHE_CLEAN in trace output
dma-debug: Allow multiple invocations of overlapping entries
dma: swiotlb: add KMSAN annotations to swiotlb_bounce()
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|
During futex_key_to_node_opt() execution, vma->vm_policy is read under
speculative mmap lock and RCU. Concurrently, mbind() may call
vma_replace_policy() which frees the old mempolicy immediately via
kmem_cache_free().
This creates a race where __futex_key_to_node() dereferences a freed
mempolicy pointer, causing a use-after-free read of mpol->mode.
[ 151.412631] BUG: KASAN: slab-use-after-free in __futex_key_to_node (kernel/futex/core.c:349)
[ 151.414046] Read of size 2 at addr ffff888001c49634 by task e/87
[ 151.415969] Call Trace:
[ 151.416732] __asan_load2 (mm/kasan/generic.c:271)
[ 151.416777] __futex_key_to_node (kernel/futex/core.c:349)
[ 151.416822] get_futex_key (kernel/futex/core.c:374 kernel/futex/core.c:386 kernel/futex/core.c:593)
Fix by adding rcu to __mpol_put().
Fixes: c042c505210d ("futex: Implement FUTEX2_MPOL")
Reported-by: Hao-Yu Yang <naup96721@gmail.com>
Suggested-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Hao-Yu Yang <naup96721@gmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Eric Dumazet <edumazet@google.com>
Acked-by: David Hildenbrand (Arm) <david@kernel.org>
Link: https://patch.msgid.link/20260324174418.GB1850007@noisy.programming.kicks-ass.net
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Nicholas reported that his LLM found it was possible to create a UaF
when sys_futex_requeue() is used with different flags. The initial
motivation for allowing different flags was the variable sized futex,
but since that hasn't been merged (yet), simply mandate the flags are
identical, as is the case for the old style sys_futex() requeue
operations.
Fixes: 0f4b5f972216 ("futex: Add sys_futex_requeue()")
Reported-by: Nicholas Carlini <npc@anthropic.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
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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>
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git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux
Pull RCU fixes from Boqun Feng:
"Fix a regression introduced by commit c27cea4416a3 ("rcu: Re-implement
RCU Tasks Trace in terms of SRCU-fast"): BPF contexts can run with
preemption disabled or scheduler locks held, so call_srcu() must work
in all such contexts.
Fix this by converting SRCU's spinlocks to raw spinlocks and avoiding
scheduler lock acquisition in call_srcu() by deferring to an irq_work
(similar to call_rcu_tasks_generic()), for both tree SRCU and tiny
SRCU.
Also fix a follow-on lockdep splat caused by srcu_node allocation
under the newly introduced raw spinlock by deferring the allocation to
grace-period worker context"
* tag 'rcu-fixes.v7.0-20260325a' of git://git.kernel.org/pub/scm/linux/kernel/git/rcu/linux:
srcu: Use irq_work to start GP in tiny SRCU
rcu: Use an intermediate irq_work to start process_srcu()
srcu: Push srcu_node allocation to GP when non-preemptible
srcu: Use raw spinlocks so call_srcu() can be used under preempt_disable()
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cgroup_drain_dying() was using cgroup_is_populated() to test whether there are
dying tasks to wait for. cgroup_is_populated() tests nr_populated_csets,
nr_populated_domain_children and nr_populated_threaded_children, but
cgroup_drain_dying() only needs to care about this cgroup's own tasks - whether
there are children is cgroup_destroy_locked()'s concern.
This caused hangs during shutdown. When systemd tried to rmdir a cgroup that had
no direct tasks but had a populated child, cgroup_drain_dying() would enter its
wait loop because cgroup_is_populated() was true from
nr_populated_domain_children. The task iterator found nothing to wait for, yet
the populated state never cleared because it was driven by live tasks in the
child cgroup.
Fix it by using cgroup_has_tasks() which only tests nr_populated_csets.
v3: Fix cgroup_is_populated() -> cgroup_has_tasks() (Sebastian).
v2: https://lore.kernel.org/r/20260323200205.1063629-1-tj@kernel.org
Reported-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Fixes: 1b164b876c36 ("cgroup: Wait for dying tasks to leave on rmdir")
Signed-off-by: Tejun Heo <tj@kernel.org>
Tested-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
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