<feed xmlns='http://www.w3.org/2005/Atom'>
<title>linux-stable.git/kernel, branch v6.2.9</title>
<subtitle>Linux kernel stable tree</subtitle>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/'/>
<entry>
<title>sched/fair: Sanitize vruntime of entity being migrated</title>
<updated>2023-03-30T10:51:42+00:00</updated>
<author>
<name>Vincent Guittot</name>
<email>vincent.guittot@linaro.org</email>
</author>
<published>2023-03-17T16:08:10+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=6cf4184211a92523ee96abaf989ee48282edfdb6'/>
<id>6cf4184211a92523ee96abaf989ee48282edfdb6</id>
<content type='text'>
commit a53ce18cacb477dd0513c607f187d16f0fa96f71 upstream.

Commit 829c1651e9c4 ("sched/fair: sanitize vruntime of entity being placed")
fixes an overflowing bug, but ignore a case that se-&gt;exec_start is reset
after a migration.

For fixing this case, we delay the reset of se-&gt;exec_start after
placing the entity which se-&gt;exec_start to detect long sleeping task.

In order to take into account a possible divergence between the clock_task
of 2 rqs, we increase the threshold to around 104 days.

Fixes: 829c1651e9c4 ("sched/fair: sanitize vruntime of entity being placed")
Originally-by: Zhang Qiao &lt;zhangqiao22@huawei.com&gt;
Signed-off-by: Vincent Guittot &lt;vincent.guittot@linaro.org&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Tested-by: Zhang Qiao &lt;zhangqiao22@huawei.com&gt;
Link: https://lore.kernel.org/r/20230317160810.107988-1-vincent.guittot@linaro.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit a53ce18cacb477dd0513c607f187d16f0fa96f71 upstream.

Commit 829c1651e9c4 ("sched/fair: sanitize vruntime of entity being placed")
fixes an overflowing bug, but ignore a case that se-&gt;exec_start is reset
after a migration.

For fixing this case, we delay the reset of se-&gt;exec_start after
placing the entity which se-&gt;exec_start to detect long sleeping task.

In order to take into account a possible divergence between the clock_task
of 2 rqs, we increase the threshold to around 104 days.

Fixes: 829c1651e9c4 ("sched/fair: sanitize vruntime of entity being placed")
Originally-by: Zhang Qiao &lt;zhangqiao22@huawei.com&gt;
Signed-off-by: Vincent Guittot &lt;vincent.guittot@linaro.org&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Tested-by: Zhang Qiao &lt;zhangqiao22@huawei.com&gt;
Link: https://lore.kernel.org/r/20230317160810.107988-1-vincent.guittot@linaro.org
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>sched/fair: sanitize vruntime of entity being placed</title>
<updated>2023-03-30T10:51:42+00:00</updated>
<author>
<name>Zhang Qiao</name>
<email>zhangqiao22@huawei.com</email>
</author>
<published>2023-01-30T12:22:16+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ab2bc893b74c489f77b9f6530a1161622aefdc76'/>
<id>ab2bc893b74c489f77b9f6530a1161622aefdc76</id>
<content type='text'>
commit 829c1651e9c4a6f78398d3e67651cef9bb6b42cc upstream.

When a scheduling entity is placed onto cfs_rq, its vruntime is pulled
to the base level (around cfs_rq-&gt;min_vruntime), so that the entity
doesn't gain extra boost when placed backwards.

However, if the entity being placed wasn't executed for a long time, its
vruntime may get too far behind (e.g. while cfs_rq was executing a
low-weight hog), which can inverse the vruntime comparison due to s64
overflow.  This results in the entity being placed with its original
vruntime way forwards, so that it will effectively never get to the cpu.

To prevent that, ignore the vruntime of the entity being placed if it
didn't execute for much longer than the characteristic sheduler time
scale.

[rkagan: formatted, adjusted commit log, comments, cutoff value]
Signed-off-by: Zhang Qiao &lt;zhangqiao22@huawei.com&gt;
Co-developed-by: Roman Kagan &lt;rkagan@amazon.de&gt;
Signed-off-by: Roman Kagan &lt;rkagan@amazon.de&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/20230130122216.3555094-1-rkagan@amazon.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 829c1651e9c4a6f78398d3e67651cef9bb6b42cc upstream.

When a scheduling entity is placed onto cfs_rq, its vruntime is pulled
to the base level (around cfs_rq-&gt;min_vruntime), so that the entity
doesn't gain extra boost when placed backwards.

However, if the entity being placed wasn't executed for a long time, its
vruntime may get too far behind (e.g. while cfs_rq was executing a
low-weight hog), which can inverse the vruntime comparison due to s64
overflow.  This results in the entity being placed with its original
vruntime way forwards, so that it will effectively never get to the cpu.

To prevent that, ignore the vruntime of the entity being placed if it
didn't execute for much longer than the characteristic sheduler time
scale.

[rkagan: formatted, adjusted commit log, comments, cutoff value]
Signed-off-by: Zhang Qiao &lt;zhangqiao22@huawei.com&gt;
Co-developed-by: Roman Kagan &lt;rkagan@amazon.de&gt;
Signed-off-by: Roman Kagan &lt;rkagan@amazon.de&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/20230130122216.3555094-1-rkagan@amazon.de
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>kcsan: avoid passing -g for test</title>
<updated>2023-03-30T10:51:38+00:00</updated>
<author>
<name>Marco Elver</name>
<email>elver@google.com</email>
</author>
<published>2023-03-16T22:47:05+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=ec4c55131de8b21ab9bc35738d25c932703ef356'/>
<id>ec4c55131de8b21ab9bc35738d25c932703ef356</id>
<content type='text'>
commit 5eb39cde1e2487ba5ec1802dc5e58a77e700d99e upstream.

Nathan reported that when building with GNU as and a version of clang that
defaults to DWARF5, the assembler will complain with:

  Error: non-constant .uleb128 is not supported

This is because `-g` defaults to the compiler debug info default. If the
assembler does not support some of the directives used, the above errors
occur. To fix, remove the explicit passing of `-g`.

All the test wants is that stack traces print valid function names, and
debug info is not required for that. (I currently cannot recall why I
added the explicit `-g`.)

Link: https://lkml.kernel.org/r/20230316224705.709984-2-elver@google.com
Fixes: 1fe84fd4a402 ("kcsan: Add test suite")
Signed-off-by: Marco Elver &lt;elver@google.com&gt;
Reported-by: Nathan Chancellor &lt;nathan@kernel.org&gt;
Cc: Alexander Potapenko &lt;glider@google.com&gt;
Cc: Dmitry Vyukov &lt;dvyukov@google.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit 5eb39cde1e2487ba5ec1802dc5e58a77e700d99e upstream.

Nathan reported that when building with GNU as and a version of clang that
defaults to DWARF5, the assembler will complain with:

  Error: non-constant .uleb128 is not supported

This is because `-g` defaults to the compiler debug info default. If the
assembler does not support some of the directives used, the above errors
occur. To fix, remove the explicit passing of `-g`.

All the test wants is that stack traces print valid function names, and
debug info is not required for that. (I currently cannot recall why I
added the explicit `-g`.)

Link: https://lkml.kernel.org/r/20230316224705.709984-2-elver@google.com
Fixes: 1fe84fd4a402 ("kcsan: Add test suite")
Signed-off-by: Marco Elver &lt;elver@google.com&gt;
Reported-by: Nathan Chancellor &lt;nathan@kernel.org&gt;
Cc: Alexander Potapenko &lt;glider@google.com&gt;
Cc: Dmitry Vyukov &lt;dvyukov@google.com&gt;
Cc: &lt;stable@vger.kernel.org&gt;
Signed-off-by: Andrew Morton &lt;akpm@linux-foundation.org&gt;
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>entry/rcu: Check TIF_RESCHED _after_ delayed RCU wake-up</title>
<updated>2023-03-30T10:51:24+00:00</updated>
<author>
<name>Frederic Weisbecker</name>
<email>frederic@kernel.org</email>
</author>
<published>2023-03-15T19:43:43+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=4d13a4f0238357f8ea2308b2c9cabb348ec83450'/>
<id>4d13a4f0238357f8ea2308b2c9cabb348ec83450</id>
<content type='text'>
[ Upstream commit b416514054810cf2d2cc348ae477cea619b64da7 ]

RCU sometimes needs to perform a delayed wake up for specific kthreads
handling offloaded callbacks (RCU_NOCB).  These wakeups are performed
by timers and upon entry to idle (also to guest and to user on nohz_full).

However the delayed wake-up on kernel exit is actually performed after
the thread flags are fetched towards the fast path check for work to
do on exit to user. As a result, and if there is no other pending work
to do upon that kernel exit, the current task will resume to userspace
with TIF_RESCHED set and the pending wake up ignored.

Fix this with fetching the thread flags _after_ the delayed RCU-nocb
kthread wake-up.

Fixes: 47b8ff194c1f ("entry: Explicitly flush pending rcuog wakeup before last rescheduling point")
Signed-off-by: Frederic Weisbecker &lt;frederic@kernel.org&gt;
Signed-off-by: Paul E. McKenney &lt;paulmck@kernel.org&gt;
Signed-off-by: Joel Fernandes (Google) &lt;joel@joelfernandes.org&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/r/20230315194349.10798-3-joel@joelfernandes.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit b416514054810cf2d2cc348ae477cea619b64da7 ]

RCU sometimes needs to perform a delayed wake up for specific kthreads
handling offloaded callbacks (RCU_NOCB).  These wakeups are performed
by timers and upon entry to idle (also to guest and to user on nohz_full).

However the delayed wake-up on kernel exit is actually performed after
the thread flags are fetched towards the fast path check for work to
do on exit to user. As a result, and if there is no other pending work
to do upon that kernel exit, the current task will resume to userspace
with TIF_RESCHED set and the pending wake up ignored.

Fix this with fetching the thread flags _after_ the delayed RCU-nocb
kthread wake-up.

Fixes: 47b8ff194c1f ("entry: Explicitly flush pending rcuog wakeup before last rescheduling point")
Signed-off-by: Frederic Weisbecker &lt;frederic@kernel.org&gt;
Signed-off-by: Paul E. McKenney &lt;paulmck@kernel.org&gt;
Signed-off-by: Joel Fernandes (Google) &lt;joel@joelfernandes.org&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/r/20230315194349.10798-3-joel@joelfernandes.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>entry: Fix noinstr warning in __enter_from_user_mode()</title>
<updated>2023-03-30T10:51:24+00:00</updated>
<author>
<name>Josh Poimboeuf</name>
<email>jpoimboe@kernel.org</email>
</author>
<published>2023-02-26T00:01:36+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=c90dc514c2e2be786159c8c2a08111fad82b3482'/>
<id>c90dc514c2e2be786159c8c2a08111fad82b3482</id>
<content type='text'>
[ Upstream commit f87d28673b71b35b248231a2086f9404afbb7f28 ]

__enter_from_user_mode() is triggering noinstr warnings with
CONFIG_DEBUG_PREEMPT due to its call of preempt_count_add() via
ct_state().

The preemption disable isn't needed as interrupts are already disabled.
And the context_tracking_enabled() check in ct_state() also isn't needed
as that's already being done by the CT_WARN_ON().

Just use __ct_state() instead.

Fixes the following warnings:

  vmlinux.o: warning: objtool: enter_from_user_mode+0xba: call to preempt_count_add() leaves .noinstr.text section
  vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0xf9: call to preempt_count_add() leaves .noinstr.text section
  vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0xc7: call to preempt_count_add() leaves .noinstr.text section
  vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0xba: call to preempt_count_add() leaves .noinstr.text section

Fixes: 171476775d32 ("context_tracking: Convert state to atomic_t")
Signed-off-by: Josh Poimboeuf &lt;jpoimboe@kernel.org&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/r/d8955fa6d68dc955dda19baf13ae014ae27926f5.1677369694.git.jpoimboe@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit f87d28673b71b35b248231a2086f9404afbb7f28 ]

__enter_from_user_mode() is triggering noinstr warnings with
CONFIG_DEBUG_PREEMPT due to its call of preempt_count_add() via
ct_state().

The preemption disable isn't needed as interrupts are already disabled.
And the context_tracking_enabled() check in ct_state() also isn't needed
as that's already being done by the CT_WARN_ON().

Just use __ct_state() instead.

Fixes the following warnings:

  vmlinux.o: warning: objtool: enter_from_user_mode+0xba: call to preempt_count_add() leaves .noinstr.text section
  vmlinux.o: warning: objtool: syscall_enter_from_user_mode+0xf9: call to preempt_count_add() leaves .noinstr.text section
  vmlinux.o: warning: objtool: syscall_enter_from_user_mode_prepare+0xc7: call to preempt_count_add() leaves .noinstr.text section
  vmlinux.o: warning: objtool: irqentry_enter_from_user_mode+0xba: call to preempt_count_add() leaves .noinstr.text section

Fixes: 171476775d32 ("context_tracking: Convert state to atomic_t")
Signed-off-by: Josh Poimboeuf &lt;jpoimboe@kernel.org&gt;
Signed-off-by: Thomas Gleixner &lt;tglx@linutronix.de&gt;
Link: https://lore.kernel.org/r/d8955fa6d68dc955dda19baf13ae014ae27926f5.1677369694.git.jpoimboe@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>bpf: Adjust insufficient default bpf_jit_limit</title>
<updated>2023-03-30T10:51:19+00:00</updated>
<author>
<name>Daniel Borkmann</name>
<email>daniel@iogearbox.net</email>
</author>
<published>2023-03-20T14:37:25+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=68ed00a37d2d1c932ff7be40be4b90c4bec48c56'/>
<id>68ed00a37d2d1c932ff7be40be4b90c4bec48c56</id>
<content type='text'>
[ Upstream commit 10ec8ca8ec1a2f04c4ed90897225231c58c124a7 ]

We've seen recent AWS EKS (Kubernetes) user reports like the following:

  After upgrading EKS nodes from v20230203 to v20230217 on our 1.24 EKS
  clusters after a few days a number of the nodes have containers stuck
  in ContainerCreating state or liveness/readiness probes reporting the
  following error:

    Readiness probe errored: rpc error: code = Unknown desc = failed to
    exec in container: failed to start exec "4a11039f730203ffc003b7[...]":
    OCI runtime exec failed: exec failed: unable to start container process:
    unable to init seccomp: error loading seccomp filter into kernel:
    error loading seccomp filter: errno 524: unknown

  However, we had not been seeing this issue on previous AMIs and it only
  started to occur on v20230217 (following the upgrade from kernel 5.4 to
  5.10) with no other changes to the underlying cluster or workloads.

  We tried the suggestions from that issue (sysctl net.core.bpf_jit_limit=452534528)
  which helped to immediately allow containers to be created and probes to
  execute but after approximately a day the issue returned and the value
  returned by cat /proc/vmallocinfo | grep bpf_jit | awk '{s+=$2} END {print s}'
  was steadily increasing.

I tested bpf tree to observe bpf_jit_charge_modmem, bpf_jit_uncharge_modmem
their sizes passed in as well as bpf_jit_current under tcpdump BPF filter,
seccomp BPF and native (e)BPF programs, and the behavior all looks sane
and expected, that is nothing "leaking" from an upstream perspective.

The bpf_jit_limit knob was originally added in order to avoid a situation
where unprivileged applications loading BPF programs (e.g. seccomp BPF
policies) consuming all the module memory space via BPF JIT such that loading
of kernel modules would be prevented. The default limit was defined back in
2018 and while good enough back then, we are generally seeing far more BPF
consumers today.

Adjust the limit for the BPF JIT pool from originally 1/4 to now 1/2 of the
module memory space to better reflect today's needs and avoid more users
running into potentially hard to debug issues.

Fixes: fdadd04931c2 ("bpf: fix bpf_jit_limit knob for PAGE_SIZE &gt;= 64K")
Reported-by: Stephen Haynes &lt;sh@synk.net&gt;
Reported-by: Lefteris Alexakis &lt;lefteris.alexakis@kpn.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Link: https://github.com/awslabs/amazon-eks-ami/issues/1179
Link: https://github.com/awslabs/amazon-eks-ami/issues/1219
Reviewed-by: Kuniyuki Iwashima &lt;kuniyu@amazon.com&gt;
Link: https://lore.kernel.org/r/20230320143725.8394-1-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 10ec8ca8ec1a2f04c4ed90897225231c58c124a7 ]

We've seen recent AWS EKS (Kubernetes) user reports like the following:

  After upgrading EKS nodes from v20230203 to v20230217 on our 1.24 EKS
  clusters after a few days a number of the nodes have containers stuck
  in ContainerCreating state or liveness/readiness probes reporting the
  following error:

    Readiness probe errored: rpc error: code = Unknown desc = failed to
    exec in container: failed to start exec "4a11039f730203ffc003b7[...]":
    OCI runtime exec failed: exec failed: unable to start container process:
    unable to init seccomp: error loading seccomp filter into kernel:
    error loading seccomp filter: errno 524: unknown

  However, we had not been seeing this issue on previous AMIs and it only
  started to occur on v20230217 (following the upgrade from kernel 5.4 to
  5.10) with no other changes to the underlying cluster or workloads.

  We tried the suggestions from that issue (sysctl net.core.bpf_jit_limit=452534528)
  which helped to immediately allow containers to be created and probes to
  execute but after approximately a day the issue returned and the value
  returned by cat /proc/vmallocinfo | grep bpf_jit | awk '{s+=$2} END {print s}'
  was steadily increasing.

I tested bpf tree to observe bpf_jit_charge_modmem, bpf_jit_uncharge_modmem
their sizes passed in as well as bpf_jit_current under tcpdump BPF filter,
seccomp BPF and native (e)BPF programs, and the behavior all looks sane
and expected, that is nothing "leaking" from an upstream perspective.

The bpf_jit_limit knob was originally added in order to avoid a situation
where unprivileged applications loading BPF programs (e.g. seccomp BPF
policies) consuming all the module memory space via BPF JIT such that loading
of kernel modules would be prevented. The default limit was defined back in
2018 and while good enough back then, we are generally seeing far more BPF
consumers today.

Adjust the limit for the BPF JIT pool from originally 1/4 to now 1/2 of the
module memory space to better reflect today's needs and avoid more users
running into potentially hard to debug issues.

Fixes: fdadd04931c2 ("bpf: fix bpf_jit_limit knob for PAGE_SIZE &gt;= 64K")
Reported-by: Stephen Haynes &lt;sh@synk.net&gt;
Reported-by: Lefteris Alexakis &lt;lefteris.alexakis@kpn.com&gt;
Signed-off-by: Daniel Borkmann &lt;daniel@iogearbox.net&gt;
Link: https://github.com/awslabs/amazon-eks-ami/issues/1179
Link: https://github.com/awslabs/amazon-eks-ami/issues/1219
Reviewed-by: Kuniyuki Iwashima &lt;kuniyu@amazon.com&gt;
Link: https://lore.kernel.org/r/20230320143725.8394-1-daniel@iogearbox.net
Signed-off-by: Alexei Starovoitov &lt;ast@kernel.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>tracing/hwlat: Replace sched_setaffinity with set_cpus_allowed_ptr</title>
<updated>2023-03-30T10:50:48+00:00</updated>
<author>
<name>Costa Shulyupin</name>
<email>costa.shul@redhat.com</email>
</author>
<published>2023-03-16T14:45:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=0ca90dc98e4f8b48c2bb67ce9b5b4bce85ef05b5'/>
<id>0ca90dc98e4f8b48c2bb67ce9b5b4bce85ef05b5</id>
<content type='text'>
[ Upstream commit 71c7a30442b724717a30d5e7d1662ba4904eb3d4 ]

There is a problem with the behavior of hwlat in a container,
resulting in incorrect output. A warning message is generated:
"cpumask changed while in round-robin mode, switching to mode none",
and the tracing_cpumask is ignored. This issue arises because
the kernel thread, hwlatd, is not a part of the container, and
the function sched_setaffinity is unable to locate it using its PID.
Additionally, the task_struct of hwlatd is already known.
Ultimately, the function set_cpus_allowed_ptr achieves
the same outcome as sched_setaffinity, but employs task_struct
instead of PID.

Test case:

  # cd /sys/kernel/tracing
  # echo 0 &gt; tracing_on
  # echo round-robin &gt; hwlat_detector/mode
  # echo hwlat &gt; current_tracer
  # unshare --fork --pid bash -c 'echo 1 &gt; tracing_on'
  # dmesg -c

Actual behavior:

[573502.809060] hwlat_detector: cpumask changed while in round-robin mode, switching to mode none

Link: https://lore.kernel.org/linux-trace-kernel/20230316144535.1004952-1-costa.shul@redhat.com

Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Fixes: 0330f7aa8ee63 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs")
Signed-off-by: Costa Shulyupin &lt;costa.shul@redhat.com&gt;
Acked-by: Daniel Bristot de Oliveira &lt;bristot@kernel.org&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit 71c7a30442b724717a30d5e7d1662ba4904eb3d4 ]

There is a problem with the behavior of hwlat in a container,
resulting in incorrect output. A warning message is generated:
"cpumask changed while in round-robin mode, switching to mode none",
and the tracing_cpumask is ignored. This issue arises because
the kernel thread, hwlatd, is not a part of the container, and
the function sched_setaffinity is unable to locate it using its PID.
Additionally, the task_struct of hwlatd is already known.
Ultimately, the function set_cpus_allowed_ptr achieves
the same outcome as sched_setaffinity, but employs task_struct
instead of PID.

Test case:

  # cd /sys/kernel/tracing
  # echo 0 &gt; tracing_on
  # echo round-robin &gt; hwlat_detector/mode
  # echo hwlat &gt; current_tracer
  # unshare --fork --pid bash -c 'echo 1 &gt; tracing_on'
  # dmesg -c

Actual behavior:

[573502.809060] hwlat_detector: cpumask changed while in round-robin mode, switching to mode none

Link: https://lore.kernel.org/linux-trace-kernel/20230316144535.1004952-1-costa.shul@redhat.com

Cc: Masami Hiramatsu &lt;mhiramat@kernel.org&gt;
Fixes: 0330f7aa8ee63 ("tracing: Have hwlat trace migrate across tracing_cpumask CPUs")
Signed-off-by: Costa Shulyupin &lt;costa.shul@redhat.com&gt;
Acked-by: Daniel Bristot de Oliveira &lt;bristot@kernel.org&gt;
Signed-off-by: Steven Rostedt (Google) &lt;rostedt@goodmis.org&gt;
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf: fix perf_event_context-&gt;time</title>
<updated>2023-03-30T10:50:48+00:00</updated>
<author>
<name>Song Liu</name>
<email>song@kernel.org</email>
</author>
<published>2023-03-13T17:16:08+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=f23e237ed3153ec462f0458f459ae5c6e4617684'/>
<id>f23e237ed3153ec462f0458f459ae5c6e4617684</id>
<content type='text'>
[ Upstream commit baf1b12a67f5b24f395baca03e442ce27cab0c18 ]

Time readers rely on perf_event_context-&gt;[time|timestamp|timeoffset] to get
accurate time_enabled and time_running for an event. The difference between
ctx-&gt;timestamp and ctx-&gt;time is the among of time when the context is not
enabled. __update_context_time(ctx, false) is used to increase timestamp,
but not time. Therefore, it should only be called in ctx_sched_in() when
EVENT_TIME was not enabled.

Fixes: 09f5e7dc7ad7 ("perf: Fix perf_event_read_local() time")
Signed-off-by: Song Liu &lt;song@kernel.org&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lkml.kernel.org/r/20230313171608.298734-1-song@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit baf1b12a67f5b24f395baca03e442ce27cab0c18 ]

Time readers rely on perf_event_context-&gt;[time|timestamp|timeoffset] to get
accurate time_enabled and time_running for an event. The difference between
ctx-&gt;timestamp and ctx-&gt;time is the among of time when the context is not
enabled. __update_context_time(ctx, false) is used to increase timestamp,
but not time. Therefore, it should only be called in ctx_sched_in() when
EVENT_TIME was not enabled.

Fixes: 09f5e7dc7ad7 ("perf: Fix perf_event_read_local() time")
Signed-off-by: Song Liu &lt;song@kernel.org&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Acked-by: Namhyung Kim &lt;namhyung@kernel.org&gt;
Link: https://lkml.kernel.org/r/20230313171608.298734-1-song@kernel.org
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf/core: Fix perf_output_begin parameter is incorrectly invoked in perf_event_bpf_output</title>
<updated>2023-03-30T10:50:48+00:00</updated>
<author>
<name>Yang Jihong</name>
<email>yangjihong1@huawei.com</email>
</author>
<published>2023-03-14T04:47:35+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=3a776fddb4e5598c8bfcd4ad094fba34f9856fc9'/>
<id>3a776fddb4e5598c8bfcd4ad094fba34f9856fc9</id>
<content type='text'>
[ Upstream commit eb81a2ed4f52be831c9fb879752d89645a312c13 ]

syzkaller reportes a KASAN issue with stack-out-of-bounds.
The call trace is as follows:
  dump_stack+0x9c/0xd3
  print_address_description.constprop.0+0x19/0x170
  __kasan_report.cold+0x6c/0x84
  kasan_report+0x3a/0x50
  __perf_event_header__init_id+0x34/0x290
  perf_event_header__init_id+0x48/0x60
  perf_output_begin+0x4a4/0x560
  perf_event_bpf_output+0x161/0x1e0
  perf_iterate_sb_cpu+0x29e/0x340
  perf_iterate_sb+0x4c/0xc0
  perf_event_bpf_event+0x194/0x2c0
  __bpf_prog_put.constprop.0+0x55/0xf0
  __cls_bpf_delete_prog+0xea/0x120 [cls_bpf]
  cls_bpf_delete_prog_work+0x1c/0x30 [cls_bpf]
  process_one_work+0x3c2/0x730
  worker_thread+0x93/0x650
  kthread+0x1b8/0x210
  ret_from_fork+0x1f/0x30

commit 267fb27352b6 ("perf: Reduce stack usage of perf_output_begin()")
use on-stack struct perf_sample_data of the caller function.

However, perf_event_bpf_output uses incorrect parameter to convert
small-sized data (struct perf_bpf_event) into large-sized data
(struct perf_sample_data), which causes memory overwriting occurs in
__perf_event_header__init_id.

Fixes: 267fb27352b6 ("perf: Reduce stack usage of perf_output_begin()")
Signed-off-by: Yang Jihong &lt;yangjihong1@huawei.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/20230314044735.56551-1-yangjihong1@huawei.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
[ Upstream commit eb81a2ed4f52be831c9fb879752d89645a312c13 ]

syzkaller reportes a KASAN issue with stack-out-of-bounds.
The call trace is as follows:
  dump_stack+0x9c/0xd3
  print_address_description.constprop.0+0x19/0x170
  __kasan_report.cold+0x6c/0x84
  kasan_report+0x3a/0x50
  __perf_event_header__init_id+0x34/0x290
  perf_event_header__init_id+0x48/0x60
  perf_output_begin+0x4a4/0x560
  perf_event_bpf_output+0x161/0x1e0
  perf_iterate_sb_cpu+0x29e/0x340
  perf_iterate_sb+0x4c/0xc0
  perf_event_bpf_event+0x194/0x2c0
  __bpf_prog_put.constprop.0+0x55/0xf0
  __cls_bpf_delete_prog+0xea/0x120 [cls_bpf]
  cls_bpf_delete_prog_work+0x1c/0x30 [cls_bpf]
  process_one_work+0x3c2/0x730
  worker_thread+0x93/0x650
  kthread+0x1b8/0x210
  ret_from_fork+0x1f/0x30

commit 267fb27352b6 ("perf: Reduce stack usage of perf_output_begin()")
use on-stack struct perf_sample_data of the caller function.

However, perf_event_bpf_output uses incorrect parameter to convert
small-sized data (struct perf_bpf_event) into large-sized data
(struct perf_sample_data), which causes memory overwriting occurs in
__perf_event_header__init_id.

Fixes: 267fb27352b6 ("perf: Reduce stack usage of perf_output_begin()")
Signed-off-by: Yang Jihong &lt;yangjihong1@huawei.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/20230314044735.56551-1-yangjihong1@huawei.com
Signed-off-by: Sasha Levin &lt;sashal@kernel.org&gt;
</pre>
</div>
</content>
</entry>
<entry>
<title>perf: Fix check before add_event_to_groups() in perf_group_detach()</title>
<updated>2023-03-22T12:38:10+00:00</updated>
<author>
<name>Budimir Markovic</name>
<email>markovicbudimir@gmail.com</email>
</author>
<published>2023-03-15T07:29:01+00:00</published>
<link rel='alternate' type='text/html' href='https://git.tavy.me/linux-stable.git/commit/?id=2c6d1b32838d8cf0114dfdbbb93f4d808e498760'/>
<id>2c6d1b32838d8cf0114dfdbbb93f4d808e498760</id>
<content type='text'>
commit fd0815f632c24878e325821943edccc7fde947a2 upstream.

Events should only be added to a groups rb tree if they have not been
removed from their context by list_del_event(). Since remove_on_exec
made it possible to call list_del_event() on individual events before
they are detached from their group, perf_group_detach() should check each
sibling's attach_state before calling add_event_to_groups() on it.

Fixes: 2e498d0a74e5 ("perf: Add support for event removal on exec")
Signed-off-by: Budimir Markovic &lt;markovicbudimir@gmail.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/ZBFzvQV9tEqoHEtH@gentoo
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</content>
<content type='xhtml'>
<div xmlns='http://www.w3.org/1999/xhtml'>
<pre>
commit fd0815f632c24878e325821943edccc7fde947a2 upstream.

Events should only be added to a groups rb tree if they have not been
removed from their context by list_del_event(). Since remove_on_exec
made it possible to call list_del_event() on individual events before
they are detached from their group, perf_group_detach() should check each
sibling's attach_state before calling add_event_to_groups() on it.

Fixes: 2e498d0a74e5 ("perf: Add support for event removal on exec")
Signed-off-by: Budimir Markovic &lt;markovicbudimir@gmail.com&gt;
Signed-off-by: Peter Zijlstra (Intel) &lt;peterz@infradead.org&gt;
Link: https://lkml.kernel.org/r/ZBFzvQV9tEqoHEtH@gentoo
Signed-off-by: Greg Kroah-Hartman &lt;gregkh@linuxfoundation.org&gt;
</pre>
</div>
</content>
</entry>
</feed>
