From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932749Ab0LHBDf (ORCPT ); Tue, 7 Dec 2010 20:03:35 -0500 Received: from kroah.org ([198.145.64.141]:33736 "EHLO coco.kroah.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932736Ab0LHBDc (ORCPT ); Tue, 7 Dec 2010 20:03:32 -0500 X-Mailbox-Line: From gregkh@clark.site Tue Dec 7 16:57:45 2010 Message-Id: <20101208005745.295405482@clark.site> User-Agent: quilt/0.48-11.2 Date: Tue, 07 Dec 2010 17:00:16 -0800 From: Greg KH To: linux-kernel@vger.kernel.org, stable@kernel.org Cc: stable-review@kernel.org, torvalds@linux-foundation.org, akpm@linux-foundation.org, alan@lxorguk.ukuu.org.uk, Ingo Molnar , Pekka Enberg Subject: [239/289] perf_events: Fix perf_counter_mmap() hook in mprotect() In-Reply-To: <20101208005821.GA2922@kroah.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2.6.36-stable review patch. If anyone has any objections, please let us know. ------------------ From: Pekka Enberg 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 Analyzed-by: Linus Torvalds Cc: Ingo Molnar Reviewed-by: Peter Zijlstra Signed-off-by: Pekka Enberg Signed-off-by: Linus Torvalds Signed-off-by: Greg Kroah-Hartman --- mm/mprotect.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -211,6 +211,7 @@ 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: @@ -299,7 +300,6 @@ SYSCALL_DEFINE3(mprotect, unsigned long, error = mprotect_fixup(vma, &prev, nstart, tmp, newflags); if (error) goto out; - perf_event_mmap(vma); nstart = tmp; if (nstart < prev->vm_end)