linux-stable.git/kernel, branch v5.13.2

cred: add missing return error code when set_cred_ucounts() failed

2021-07-14T15:07:52+00:00

commit 5e6b8a50a7cec5686ee2c4bda1d49899c79a7eae upstream.

If set_cred_ucounts() failed, we need return the error code.

Fixes: 905ae01c4ae2 ("Add a reference to ucounts for each cred")
Reported-by: Hulk Robot 
Signed-off-by: Yang Yingliang 
Link: https://lkml.kernel.org/r/20210526143805.2549649-1-yangyingliang@huawei.com
Reviewed-by: Alexey Gladkov 
Signed-off-by: Eric W. Biederman 
Signed-off-by: Greg Kroah-Hartman

sched: Stop PF_NO_SETAFFINITY from being inherited by various init system threads

2021-07-14T15:07:51+00:00

commit a8ea6fc9b089156d9230bfeef964dd9be101a4a9 upstream.

Commit:

00b89fe0197f ("sched: Make the idle task quack like a per-CPU kthread")

... added PF_KTHREAD | PF_NO_SETAFFINITY to the idle kernel threads.

Unfortunately these properties are inherited to the init/0 children
through kernel_thread() calls: init/1 and kthreadd. There are several
side effects to that:

1) kthreadd affinity can not be reset anymore from userspace. Also
PF_NO_SETAFFINITY propagates to all kthreadd children, including
the unbound kthreads Therefore it's not possible anymore to overwrite
the affinity of any of them. Here is an example of warning reported
by rcutorture:

WARNING: CPU: 0 PID: 116 at kernel/rcu/tree_nocb.h:1306 rcu_bind_current_to_nocb+0x31/0x40
Call Trace:
rcu_torture_fwd_prog+0x62/0x730
kthread+0x122/0x140
ret_from_fork+0x22/0x30

2) init/1 does an exec() in the end which clears both
PF_KTHREAD and PF_NO_SETAFFINITY so we are fine once kernel_init()
escapes to userspace. But until then, no initcall or init code can
successfully call sched_setaffinity() to init/1.

Also PF_KTHREAD looks legit on init/1 before it calls exec() but
we better be careful with unknown introduced side effects.

One way to solve the PF_NO_SETAFFINITY issue is to not inherit this flag
on copy_process() at all. The cases where it matters are:

* fork_idle(): explicitly set the flag already.
* fork() syscalls: userspace tasks that shouldn't be concerned by that.
* create_io_thread(): the callers explicitly attribute the flag to the
newly created tasks.
* kernel_thread():
- Fix the issues on init/1 and kthreadd
- Fix the issues on kthreadd children.
- Usermode helper created by an unbound workqueue. This shouldn't
matter. In the worst case it gives more control to userspace
on setting affinity to these short living tasks although this can
be tuned with inherited unbound workqueues affinity already.

Fixes: 00b89fe0197f ("sched: Make the idle task quack like a per-CPU kthread")
Reported-by: Paul E. McKenney
Signed-off-by: Frederic Weisbecker
Signed-off-by: Ingo Molnar
Tested-by: Paul E. McKenney
Link: https://lore.kernel.org/r/20210525235849.441842-1-frederic@kernel.org
Signed-off-by: Greg Kroah-Hartman

rcu: Invoke rcu_spawn_core_kthreads() from rcu_spawn_gp_kthread()

2021-07-14T15:07:25+00:00

[ Upstream commit 8e4b1d2bc198e34b48fc7cc3a3c5a2fcb269e271 ]

Currently, rcu_spawn_core_kthreads() is invoked via an early_initcall(),
which works, except that rcu_spawn_gp_kthread() is also invoked via an
early_initcall() and rcu_spawn_core_kthreads() relies on adjustments to
kthread_prio that are carried out by rcu_spawn_gp_kthread().  There is
no guaranttee of ordering among early_initcall() handlers, and thus no
guarantee that kthread_prio will be properly checked and range-limited
at the time that rcu_spawn_core_kthreads() needs it.

In most cases, this bug is harmless.  After all, the only reason that
rcu_spawn_gp_kthread() adjusts the value of kthread_prio is if the user
specified a nonsensical value for this boot parameter, which experience
indicates is rare.

Nevertheless, a bug is a bug.  This commit therefore causes the
rcu_spawn_core_kthreads() function to be invoked directly from
rcu_spawn_gp_kthread() after any needed adjustments to kthread_prio have
been carried out.

Fixes: 48d07c04b4cc ("rcu: Enable elimination of Tree-RCU softirq processing")
Signed-off-by: Paul E. McKenney 
Signed-off-by: Sasha Levin

bpf: Fix null ptr deref with mixed tail calls and subprogs

2021-07-14T15:07:16+00:00

[ Upstream commit 7506d211b932870155bcb39e3dd9e39fab45a7c7 ]

The sub-programs prog->aux->poke_tab[] is populated in jit_subprogs() and
then used when emitting 'BPF_JMP|BPF_TAIL_CALL' insn->code from the
individual JITs. The poke_tab[] to use is stored in the insn->imm by
the code adding it to that array slot. The JIT then uses imm to find the
right entry for an individual instruction. In the x86 bpf_jit_comp.c
this is done by calling emit_bpf_tail_call_direct with the poke_tab[]
of the imm value.

However, we observed the below null-ptr-deref when mixing tail call
programs with subprog programs. For this to happen we just need to
mix bpf-2-bpf calls and tailcalls with some extra calls or instructions
that would be patched later by one of the fixup routines. So whats
happening?

Before the fixup_call_args() -- where the jit op is done -- various
code patching is done by do_misc_fixups(). This may increase the
insn count, for example when we patch map_lookup_up using map_gen_lookup
hook. This does two things. First, it means the instruction index,
insn_idx field, of a tail call instruction will move by a 'delta'.

In verifier code,

 struct bpf_jit_poke_descriptor desc = {
  .reason = BPF_POKE_REASON_TAIL_CALL,
  .tail_call.map = BPF_MAP_PTR(aux->map_ptr_state),
  .tail_call.key = bpf_map_key_immediate(aux),
  .insn_idx = i + delta,
 };

Then subprog start values subprog_info[i].start will be updated
with the delta and any poke descriptor index will also be updated
with the delta in adjust_poke_desc(). If we look at the adjust
subprog starts though we see its only adjusted when the delta
occurs before the new instructions,

        /* NOTE: fake 'exit' subprog should be updated as well. */
        for (i = 0; i <= env->subprog_cnt; i++) {
                if (env->subprog_info[i].start <= off)
                        continue;

Earlier subprograms are not changed because their start values
are not moved. But, adjust_poke_desc() does the offset + delta
indiscriminately. The result is poke descriptors are potentially
corrupted.

Then in jit_subprogs() we only populate the poke_tab[]
when the above insn_idx is less than the next subprogram start. From
above we corrupted our insn_idx so we might incorrectly assume a
poke descriptor is not used in a subprogram omitting it from the
subprogram. And finally when the jit runs it does the deref of poke_tab
when emitting the instruction and crashes with below. Because earlier
step omitted the poke descriptor.

The fix is straight forward with above context. Simply move same logic
from adjust_subprog_starts() into adjust_poke_descs() and only adjust
insn_idx when needed.

[   82.396354] bpf_testmod: version magic '5.12.0-rc2alu+ SMP preempt mod_unload ' should be '5.12.0+ SMP preempt mod_unload '
[   82.623001] loop10: detected capacity change from 0 to 8
[   88.487424] ==================================================================
[   88.487438] BUG: KASAN: null-ptr-deref in do_jit+0x184a/0x3290
[   88.487455] Write of size 8 at addr 0000000000000008 by task test_progs/5295
[   88.487471] CPU: 7 PID: 5295 Comm: test_progs Tainted: G          I       5.12.0+ #386
[   88.487483] Hardware name: Dell Inc. Precision 5820 Tower/002KVM, BIOS 1.9.2 01/24/2019
[   88.487490] Call Trace:
[   88.487498]  dump_stack+0x93/0xc2
[   88.487515]  kasan_report.cold+0x5f/0xd8
[   88.487530]  ? do_jit+0x184a/0x3290
[   88.487542]  do_jit+0x184a/0x3290
 ...
[   88.487709]  bpf_int_jit_compile+0x248/0x810
 ...
[   88.487765]  bpf_check+0x3718/0x5140
 ...
[   88.487920]  bpf_prog_load+0xa22/0xf10

Fixes: a748c6975dea3 ("bpf: propagate poke descriptors to subprograms")
Reported-by: Jussi Maki 
Signed-off-by: John Fastabend 
Signed-off-by: Alexei Starovoitov 
Reviewed-by: Daniel Borkmann 
Signed-off-by: Sasha Levin

bpf: Fix integer overflow in argument calculation for bpf_map_area_alloc

2021-07-14T15:07:15+00:00

[ Upstream commit 7dd5d437c258bbf4cc15b35229e5208b87b8b4e0 ]

In 32-bit architecture, the result of sizeof() is a 32-bit integer so
the expression becomes the multiplication between 2 32-bit integer which
can potentially leads to integer overflow. As a result,
bpf_map_area_alloc() allocates less memory than needed.

Fix this by casting 1 operand to u64.

Fixes: 0d2c4f964050 ("bpf: Eliminate rlimit-based memory accounting for sockmap and sockhash maps")
Fixes: 99c51064fb06 ("devmap: Use bpf_map_area_alloc() for allocating hash buckets")
Fixes: 546ac1ffb70d ("bpf: add devmap, a map for storing net device references")
Signed-off-by: Bui Quang Minh 
Signed-off-by: Alexei Starovoitov 
Link: https://lore.kernel.org/bpf/20210613143440.71975-1-minhquangbui99@gmail.com
Signed-off-by: Sasha Levin

bpf: Fix regression on BPF_OBJ_GET with non-O_RDWR flags

2021-07-14T15:07:14+00:00

[ Upstream commit 5dec6d96d12d33900ec315972c8e47a73bcc378d ]

This reverts commit d37300ed1821 ("bpf: program: Refuse non-O_RDWR flags
in BPF_OBJ_GET"). It breaks Android userspace which expects to be able to
fetch programs with just read permissions.

See: https://cs.android.com/android/platform/superproject/+/master:frameworks/libs/net/common/native/bpf_syscall_wrappers/include/BpfSyscallWrappers.h;drc=7005c764be23d31fa1d69e826b4a2f6689a8c81e;l=124

Side-note: another option to fix it would be to extend bpf_prog_new_fd()
and to pass in used file mode flags in the same way as we do for maps via
bpf_map_new_fd(). Meaning, they'd end up in anon_inode_getfd() and thus
would be retained for prog fd operations with bpf() syscall. Right now
these flags are not checked with progs since they are immutable for their
lifetime (as opposed to maps which can be updated from user space). In
future this could potentially change with new features, but at that point
it's still fine to do the bpf_prog_new_fd() extension when needed. For a
simple stable fix, a revert is less churn.

Fixes: d37300ed1821 ("bpf: program: Refuse non-O_RDWR flags in BPF_OBJ_GET")
Signed-off-by: Maciej Żenczykowski 
[ Daniel: added side-note to commit message ]
Signed-off-by: Daniel Borkmann 
Acked-by: Lorenz Bauer 
Acked-by: Greg Kroah-Hartman 
Link: https://lore.kernel.org/bpf/20210618105526.265003-1-zenczykowski@gmail.com
Signed-off-by: Sasha Levin

psi: Fix race between psi_trigger_create/destroy

2021-07-14T15:06:49+00:00

[ Upstream commit 8f91efd870ea5d8bc10b0fcc9740db51cd4c0c83 ]

Race detected between psi_trigger_destroy/create as shown below, which
cause panic by accessing invalid psi_system->poll_wait->wait_queue_entry
and psi_system->poll_timer->entry->next. Under this modification, the
race window is removed by initialising poll_wait and poll_timer in
group_init which are executed only once at beginning.

  psi_trigger_destroy()                   psi_trigger_create()

  mutex_lock(trigger_lock);
  rcu_assign_pointer(poll_task, NULL);
  mutex_unlock(trigger_lock);
					  mutex_lock(trigger_lock);
					  if (!rcu_access_pointer(group->poll_task)) {
					    timer_setup(poll_timer, poll_timer_fn, 0);
					    rcu_assign_pointer(poll_task, task);
					  }
					  mutex_unlock(trigger_lock);

  synchronize_rcu();
  del_timer_sync(poll_timer); <-- poll_timer has been reinitialized by
                                  psi_trigger_create()

So, trigger_lock/RCU correctly protects destruction of
group->poll_task but misses this race affecting poll_timer and
poll_wait.

Fixes: 461daba06bdc ("psi: eliminate kthread_worker from psi trigger scheduling mechanism")
Co-developed-by: ziwei.dai 
Signed-off-by: ziwei.dai 
Co-developed-by: ke.wang 
Signed-off-by: ke.wang 
Signed-off-by: Zhaoyang Huang 
Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Suren Baghdasaryan 
Acked-by: Johannes Weiner 
Link: https://lkml.kernel.org/r/1623371374-15664-1-git-send-email-huangzhaoyang@gmail.com
Signed-off-by: Sasha Levin

perf: Fix task context PMU for Hetero

2021-07-14T15:06:49+00:00

[ Upstream commit 012669c740e6e2afa8bdb95394d06676f933dd2d ]

On HETEROGENEOUS hardware (ARM big.Little, Intel Alderlake etc.) each
CPU might have a different hardware PMU. Since each such PMU is
represented by a different struct pmu, but we only have a single HW
task context.

That means that the task context needs to switch PMU type when it
switches CPUs.

Not doing this means that ctx->pmu calls (pmu_{dis,en}able(),
{start,commit,cancel}_txn() etc.) are called against the wrong PMU and
things will go wobbly.

Fixes: f83d2f91d259 ("perf/x86/intel: Add Alder Lake Hybrid support")
Reported-by: Kan Liang 
Signed-off-by: Peter Zijlstra (Intel) 
Tested-by: Kan Liang 
Link: https://lkml.kernel.org/r/YMsy7BuGT8nBTspT@hirez.programming.kicks-ass.net
Signed-off-by: Sasha Levin

lockdep: Fix wait-type for empty stack

2021-07-14T15:06:48+00:00

[ Upstream commit f8b298cc39f0619544c607eaef09fd0b2afd10f3 ]

Even the very first lock can violate the wait-context check, consider
the various IRQ contexts.

Fixes: de8f5e4f2dc1 ("lockdep: Introduce wait-type checks")
Signed-off-by: Peter Zijlstra (Intel) 
Tested-by: Joerg Roedel 
Link: https://lore.kernel.org/r/20210617190313.256987481@infradead.org
Signed-off-by: Sasha Levin

sched/uclamp: Fix uclamp_tg_restrict()

2021-07-14T15:06:48+00:00

[ Upstream commit 0213b7083e81f4acd69db32cb72eb4e5f220329a ]

Now cpu.uclamp.min acts as a protection, we need to make sure that the
uclamp request of the task is within the allowed range of the cgroup,
that is it is clamp()'ed correctly by tg->uclamp[UCLAMP_MIN] and
tg->uclamp[UCLAMP_MAX].

As reported by Xuewen [1] we can have some corner cases where there's
inversion between uclamp requested by task (p) and the uclamp values of
the taskgroup it's attached to (tg). Following table demonstrates
2 corner cases:

	           |  p  |  tg  |  effective
	-----------+-----+------+-----------
	CASE 1
	-----------+-----+------+-----------
	uclamp_min | 60% | 0%   |  60%
	-----------+-----+------+-----------
	uclamp_max | 80% | 50%  |  50%
	-----------+-----+------+-----------
	CASE 2
	-----------+-----+------+-----------
	uclamp_min | 0%  | 30%  |  30%
	-----------+-----+------+-----------
	uclamp_max | 20% | 50%  |  20%
	-----------+-----+------+-----------

With this fix we get:

	           |  p  |  tg  |  effective
	-----------+-----+------+-----------
	CASE 1
	-----------+-----+------+-----------
	uclamp_min | 60% | 0%   |  50%
	-----------+-----+------+-----------
	uclamp_max | 80% | 50%  |  50%
	-----------+-----+------+-----------
	CASE 2
	-----------+-----+------+-----------
	uclamp_min | 0%  | 30%  |  30%
	-----------+-----+------+-----------
	uclamp_max | 20% | 50%  |  30%
	-----------+-----+------+-----------

Additionally uclamp_update_active_tasks() must now unconditionally
update both UCLAMP_MIN/MAX because changing the tg's UCLAMP_MAX for
instance could have an impact on the effective UCLAMP_MIN of the tasks.

	           |  p  |  tg  |  effective
	-----------+-----+------+-----------
	old
	-----------+-----+------+-----------
	uclamp_min | 60% | 0%   |  50%
	-----------+-----+------+-----------
	uclamp_max | 80% | 50%  |  50%
	-----------+-----+------+-----------
	*new*
	-----------+-----+------+-----------
	uclamp_min | 60% | 0%   | *60%*
	-----------+-----+------+-----------
	uclamp_max | 80% |*70%* | *70%*
	-----------+-----+------+-----------

[1] https://lore.kernel.org/lkml/CAB8ipk_a6VFNjiEnHRHkUMBKbA+qzPQvhtNjJ_YNzQhqV_o8Zw@mail.gmail.com/

Fixes: 0c18f2ecfcc2 ("sched/uclamp: Fix wrong implementation of cpu.uclamp.min")
Reported-by: Xuewen Yan 
Signed-off-by: Qais Yousef 
Signed-off-by: Peter Zijlstra (Intel) 
Link: https://lkml.kernel.org/r/20210617165155.3774110-1-qais.yousef@arm.com
Signed-off-by: Sasha Levin