47 lines
1.7 KiB
Diff
47 lines
1.7 KiB
Diff
From: Pekka Enberg <penberg@kernel.org>
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Date: Mon, 8 Nov 2010 19:29:07 +0000 (+0200)
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Subject: perf_events: Fix perf_counter_mmap() hook in mprotect()
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X-Git-Tag: v2.6.37-rc2~72
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X-Git-Url: http://git.kernel.org/?p=linux%2Fkernel%2Fgit%2Ftorvalds%2Flinux-2.6.git;a=commitdiff_plain;h=63bfd7384b119409685a17d5c58f0b56e5dc03da
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perf_events: Fix perf_counter_mmap() hook in mprotect()
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As pointed out by Linus, commit dab5855 ("perf_counter: Add mmap event hooks to
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mprotect()") is fundamentally wrong as mprotect_fixup() can free 'vma' due to
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merging. Fix the problem by moving perf_event_mmap() hook to
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mprotect_fixup().
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Note: there's another successful return path from mprotect_fixup() if old
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flags equal to new flags. We don't, however, need to call
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perf_event_mmap() there because 'perf' already knows the VMA is
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executable.
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Reported-by: Dave Jones <davej@redhat.com>
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Analyzed-by: Linus Torvalds <torvalds@linux-foundation.org>
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Cc: Ingo Molnar <mingo@elte.hu>
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Reviewed-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
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Signed-off-by: Pekka Enberg <penberg@kernel.org>
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Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
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---
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diff --git a/mm/mprotect.c b/mm/mprotect.c
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index 2d1bf7c..4c51338 100644
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--- a/mm/mprotect.c
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+++ b/mm/mprotect.c
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@@ -211,6 +211,7 @@ success:
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mmu_notifier_invalidate_range_end(mm, start, end);
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vm_stat_account(mm, oldflags, vma->vm_file, -nrpages);
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vm_stat_account(mm, newflags, vma->vm_file, nrpages);
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+ perf_event_mmap(vma);
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return 0;
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fail:
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@@ -299,7 +300,6 @@ SYSCALL_DEFINE3(mprotect, unsigned long, start, size_t, len,
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error = mprotect_fixup(vma, &prev, nstart, tmp, newflags);
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if (error)
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goto out;
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- perf_event_mmap(vma);
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nstart = tmp;
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if (nstart < prev->vm_end)
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