From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753275AbaJCF2L (ORCPT ); Fri, 3 Oct 2014 01:28:11 -0400 Received: from terminus.zytor.com ([198.137.202.10]:60815 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752552AbaJCF2G (ORCPT ); Fri, 3 Oct 2014 01:28:06 -0400 Date: Thu, 2 Oct 2014 22:27:13 -0700 From: tip-bot for Peter Zijlstra Message-ID: Cc: mingo@kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, acme@kernel.org, atomlin@redhat.com, riel@redhat.com, akpm@linux-foundation.org, sylvain.hitier@gmail.com, tglx@linutronix.de, oleg@redhat.com, vdavydov@parallels.com, rientjes@google.com, linux-kernel@vger.kernel.org, hpa@zytor.com, paulus@samba.org, daeseok.youn@gmail.com, stable@vger.kernel.org, keescook@chromium.org Reply-To: mingo@kernel.org, torvalds@linux-foundation.org, peterz@infradead.org, atomlin@redhat.com, acme@kernel.org, riel@redhat.com, akpm@linux-foundation.org, sylvain.hitier@gmail.com, oleg@redhat.com, tglx@linutronix.de, rientjes@google.com, vdavydov@parallels.com, linux-kernel@vger.kernel.org, hpa@zytor.com, paulus@samba.org, daeseok.youn@gmail.com, stable@vger.kernel.org, keescook@chromium.org In-Reply-To: <20140929101201.GE5430@worktop> References: <20140929101201.GE5430@worktop> To: linux-tip-commits@vger.kernel.org Subject: [tip:perf/urgent] perf: Fix perf bug in fork() Git-Commit-ID: 9c2b9d30e28559a78c9e431cdd7f2c6bf5a9ee67 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: 9c2b9d30e28559a78c9e431cdd7f2c6bf5a9ee67 Gitweb: http://git.kernel.org/tip/9c2b9d30e28559a78c9e431cdd7f2c6bf5a9ee67 Author: Peter Zijlstra AuthorDate: Mon, 29 Sep 2014 12:12:01 +0200 Committer: Ingo Molnar CommitDate: Fri, 3 Oct 2014 05:41:08 +0200 perf: Fix perf bug in fork() Oleg noticed that a cleanup by Sylvain actually uncovered a bug; by calling perf_event_free_task() when failing sched_fork() we will not yet have done the memset() on ->perf_event_ctxp[] and will therefore try and 'free' the inherited contexts, which are still in use by the parent process. This is bad and might explain some outstanding fuzzer failures ... Suggested-by: Oleg Nesterov Reported-by: Oleg Nesterov Reported-by: Sylvain 'ythier' Hitier Signed-off-by: Peter Zijlstra (Intel) Cc: Aaron Tomlin Cc: Andrew Morton Cc: Arnaldo Carvalho de Melo Cc: Daeseok Youn Cc: David Rientjes Cc: Kees Cook Cc: Linus Torvalds Cc: Paul Mackerras Cc: Rik van Riel Cc: Vladimir Davydov Cc: Link: http://lkml.kernel.org/r/20140929101201.GE5430@worktop Signed-off-by: Ingo Molnar --- kernel/events/core.c | 4 +++- kernel/fork.c | 5 +++-- 2 files changed, 6 insertions(+), 3 deletions(-) diff --git a/kernel/events/core.c b/kernel/events/core.c index afdd9e1..658f232 100644 --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -7956,8 +7956,10 @@ int perf_event_init_task(struct task_struct *child) for_each_task_context_nr(ctxn) { ret = perf_event_init_context(child, ctxn); - if (ret) + if (ret) { + perf_event_free_task(child); return ret; + } } return 0; diff --git a/kernel/fork.c b/kernel/fork.c index 0cf9cdb..a91e47d 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -1360,7 +1360,7 @@ static struct task_struct *copy_process(unsigned long clone_flags, goto bad_fork_cleanup_policy; retval = audit_alloc(p); if (retval) - goto bad_fork_cleanup_policy; + goto bad_fork_cleanup_perf; /* copy all the process information */ shm_init_task(p); retval = copy_semundo(clone_flags, p); @@ -1566,8 +1566,9 @@ bad_fork_cleanup_semundo: exit_sem(p); bad_fork_cleanup_audit: audit_free(p); -bad_fork_cleanup_policy: +bad_fork_cleanup_perf: perf_event_free_task(p); +bad_fork_cleanup_policy: #ifdef CONFIG_NUMA mpol_put(p->mempolicy); bad_fork_cleanup_threadgroup_lock: