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lockdep/mm: Fix might_fault() lockdep check of current->mm->mmap_lock

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[ Upstream commit a1b65f3f7c6f7f0a08a7dba8be458c6415236487 ]

Turns out that this commit, about 10 years ago:

  9ec23531fd ("sched/preempt, mm/fault: Trigger might_sleep() in might_fault() with disabled pagefaults")

... accidentally (and unnessecarily) put the lockdep part of
__might_fault() under CONFIG_DEBUG_ATOMIC_SLEEP=y.

This is potentially notable because large distributions such as
Ubuntu are running with !CONFIG_DEBUG_ATOMIC_SLEEP.

Restore the debug check.

[ mingo: Update changelog. ]

Fixes: 9ec23531fd ("sched/preempt, mm/fault: Trigger might_sleep() in might_fault() with disabled pagefaults")
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Link: https://lore.kernel.org/r/20241104135517.536628371@infradead.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Peter Zijlstra 2024-11-04 14:39:10 +01:00 committed by Greg Kroah-Hartman
parent 2380b9f5aa
commit 53d472f972
1 changed files with 0 additions and 2 deletions
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2
mm/memory.c
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@ -5848,10 +5848,8 @@ void __might_fault(const char *file, int line)
if (pagefault_disabled())
return;
__might_sleep(file, line);
#if defined(CONFIG_DEBUG_ATOMIC_SLEEP)
if (current->mm)
might_lock_read(&current->mm->mmap_lock);
#endif
}
EXPORT_SYMBOL(__might_fault);
#endif