From: Pekka Enberg <penberg@kernel.org>
Date: Mon, 8 Nov 2010 19:29:07 +0000 (+0200)
Subject: perf_events: Fix perf_counter_mmap() hook in mprotect()
X-Git-Tag: v2.6.37-rc2~72
X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=63bfd7384b119409685a17d5c58f0b56e5dc03da;p=pandora-kernel.git

perf_events: Fix perf_counter_mmap() hook in mprotect()

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>
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