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| author | Pekka Enberg <penberg@kernel.org> | 2010-11-08 21:29:07 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-12-09 13:27:03 -0800 |
| commit | 8d5be245dde97e848d0a52340e1fecbec829eb0f (patch) | |
| tree | 568b4fa92c65f1c0e056ec62289ba767125a9b1d /mm | |
| parent | 38e6b47228e9a04b90f79b91a9569d2d21288444 (diff) | |
| download | lwn-8d5be245dde97e848d0a52340e1fecbec829eb0f.tar.gz lwn-8d5be245dde97e848d0a52340e1fecbec829eb0f.zip | |
perf_events: Fix perf_counter_mmap() hook in mprotect()
commit 63bfd7384b119409685a17d5c58f0b56e5dc03da upstream.
As pointed out by Linus, commit dab5855 ("perf_counter: Add mmap event hooks to
mprotect()") is fundamentally wrong as mprotect_fixup() can free 'vma' due to
merging. Fix the problem by moving perf_event_mmap() hook to
mprotect_fixup().
Note: there's another successful return path from mprotect_fixup() if old
flags equal to new flags. We don't, however, need to call
perf_event_mmap() there because 'perf' already knows the VMA is
executable.
Reported-by: Dave Jones <davej@redhat.com>
Analyzed-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Pekka Enberg <penberg@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'mm')
| -rw-r--r-- | mm/mprotect.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/mprotect.c b/mm/mprotect.c index 8bc969d8112d..1737c7e7af53 100644 --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -212,6 +212,7 @@ success: mmu_notifier_invalidate_range_end(mm, start, end); vm_stat_account(mm, oldflags, vma->vm_file, -nrpages); vm_stat_account(mm, newflags, vma->vm_file, nrpages); + perf_event_mmap(vma); return 0; fail: @@ -300,7 +301,6 @@ SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len, error = mprotect_fixup(vma, &prev, nstart, tmp, newflags); if (error) goto out; - perf_event_mmap(vma); nstart = tmp; if (nstart < prev->vm_end) |