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A single fix for perf:

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perf_event_clear_cpumask() uses list_for_each_entry_rcu() without being
   in a RCU read side critical section, which triggers a "suspicious RCU
   usage" warning.
 
   It turns out that the list walk does not be RCU protected because the
   write side lock is held in this contxt.
 
   Change it to a regular list walk.
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Merge tag 'perf-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

Pull perf fix from Thomas Gleixner:
 "perf_event_clear_cpumask() uses list_for_each_entry_rcu() without
  being in a RCU read side critical section, which triggers a
  'suspicious RCU usage' warning.

  It turns out that the list walk does not be RCU protected because the
  write side lock is held in this context.

  Change it to a regular list walk"

* tag 'perf-urgent-2024-11-03' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf: Fix missing RCU reader protection in perf_event_clear_cpumask()
This commit is contained in:
Linus Torvalds 2024-11-03 08:13:52 -10:00
commit 68f05b251b
1 changed files with 1 additions and 1 deletions
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2
kernel/events/core.c
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@ -13959,7 +13959,7 @@ static void perf_event_clear_cpumask(unsigned int cpu)
}
/* migrate */
list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
list_for_each_entry(pmu, &pmus, entry) {
if (pmu->scope == PERF_PMU_SCOPE_NONE ||
WARN_ON_ONCE(pmu->scope >= PERF_PMU_MAX_SCOPE))
continue;