From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753682AbcHRIJx (ORCPT ); Thu, 18 Aug 2016 04:09:53 -0400 Received: from terminus.zytor.com ([198.137.202.10]:54222 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752936AbcHRIJs (ORCPT ); Thu, 18 Aug 2016 04:09:48 -0400 Date: Thu, 18 Aug 2016 01:07:34 -0700 From: tip-bot for Oleg Nesterov Message-ID: Cc: hpa@zytor.com, vdavydov@virtuozzo.com, oleg@redhat.com, mingo@kernel.org, alexander.shishkin@linux.intel.com, torvalds@linux-foundation.org, bblanco@plumgrid.com, tglx@linutronix.de, acme@kernel.org, jolsa@redhat.com, acme@redhat.com, mhocko@kernel.org, hannes@cmpxchg.org, alexei.starovoitov@gmail.com, peterz@infradead.org, linux-kernel@vger.kernel.org Reply-To: bblanco@plumgrid.com, jolsa@redhat.com, acme@kernel.org, tglx@linutronix.de, acme@redhat.com, mhocko@kernel.org, hannes@cmpxchg.org, alexei.starovoitov@gmail.com, peterz@infradead.org, linux-kernel@vger.kernel.org, hpa@zytor.com, vdavydov@virtuozzo.com, alexander.shishkin@linux.intel.com, torvalds@linux-foundation.org, mingo@kernel.org, oleg@redhat.com In-Reply-To: <20160817153629.GB29724@redhat.com> References: <20160817153629.GB29724@redhat.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/urgent] uprobes: Fix the memcg accounting Git-Commit-ID: 6c4687cc17a788a6dd8de3e27dbeabb7cbd3e066 X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 6c4687cc17a788a6dd8de3e27dbeabb7cbd3e066 Gitweb: http://git.kernel.org/tip/6c4687cc17a788a6dd8de3e27dbeabb7cbd3e066 Author: Oleg Nesterov AuthorDate: Wed, 17 Aug 2016 17:36:29 +0200 Committer: Ingo Molnar CommitDate: Thu, 18 Aug 2016 10:03:26 +0200 uprobes: Fix the memcg accounting __replace_page() wronlgy calls mem_cgroup_cancel_charge() in "success" path, it should only do this if page_check_address() fails. This means that every enable/disable leads to unbalanced mem_cgroup_uncharge() from put_page(old_page), it is trivial to underflow the page_counter->count and trigger OOM. Reported-and-tested-by: Brenden Blanco Signed-off-by: Oleg Nesterov Reviewed-by: Johannes Weiner Acked-by: Michal Hocko Cc: Alexander Shishkin Cc: Alexei Starovoitov Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Vladimir Davydov Cc: stable@vger.kernel.org # 3.17+ Fixes: 00501b531c47 ("mm: memcontrol: rewrite charge API") Link: http://lkml.kernel.org/r/20160817153629.GB29724@redhat.com Signed-off-by: Ingo Molnar --- kernel/events/uprobes.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c index b7a525a..8c50276 100644 --- a/kernel/events/uprobes.c +++ b/kernel/events/uprobes.c @@ -172,8 +172,10 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr, mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end); err = -EAGAIN; ptep = page_check_address(page, mm, addr, &ptl, 0); - if (!ptep) + if (!ptep) { + mem_cgroup_cancel_charge(kpage, memcg, false); goto unlock; + } get_page(kpage); page_add_new_anon_rmap(kpage, vma, addr, false); @@ -200,7 +202,6 @@ static int __replace_page(struct vm_area_struct *vma, unsigned long addr, err = 0; unlock: - mem_cgroup_cancel_charge(kpage, memcg, false); mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end); unlock_page(page); return err;