From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752297AbdCPNBH (ORCPT ); Thu, 16 Mar 2017 09:01:07 -0400 Received: from bombadil.infradead.org ([65.50.211.133]:54968 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752041AbdCPNAR (ORCPT ); Thu, 16 Mar 2017 09:00:17 -0400 Message-Id: <20170316125823.190342547@infradead.org> User-Agent: quilt/0.63-1 Date: Thu, 16 Mar 2017 13:47:49 +0100 From: Peter Zijlstra To: mingo@kernel.org Cc: linux-kernel@vger.kernel.org, acme@kernel.org, mathieu.desnoyers@efficios.com, alexander.shishkin@linux.intel.com, dvyukov@google.com, fweisbec@gmail.com, oleg@redhat.com, peterz@infradead.org, stable@vger.kernel.org Subject: [PATCH 2/4] perf: Fix event inheritance on fork() References: <20170316124747.804596354@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline; filename=peterz-perf-fix-perf_event_init_context.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org While hunting for clues to a use-after-free, Oleg spotted that perf_event_init_context() can loose an error value with the result that fork() can succeed even though we did not fully inherit the perf event context. Cc: Arnaldo Carvalho de Melo Cc: Mathieu Desnoyers Cc: Ingo Molnar Cc: Alexander Shishkin Cc: stable@vger.kernel.org Cc: Dmitry Vyukov Cc: Frederic Weisbecker Spotted-by: Oleg Nesterov Fixes: 889ff0150661 ("perf/core: Split context's event group list into pinned and non-pinned lists") Signed-off-by: Peter Zijlstra (Intel) --- kernel/events/core.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) --- a/kernel/events/core.c +++ b/kernel/events/core.c @@ -10820,7 +10819,7 @@ static int perf_event_init_context(struc ret = inherit_task_group(event, parent, parent_ctx, child, ctxn, &inherited_all); if (ret) - break; + goto out_unlock; } /* @@ -10836,7 +10835,7 @@ static int perf_event_init_context(struc ret = inherit_task_group(event, parent, parent_ctx, child, ctxn, &inherited_all); if (ret) - break; + goto out_unlock; } raw_spin_lock_irqsave(&parent_ctx->lock, flags); @@ -10864,6 +10863,7 @@ static int perf_event_init_context(struc } raw_spin_unlock_irqrestore(&parent_ctx->lock, flags); +out_unlock: mutex_unlock(&parent_ctx->mutex); perf_unpin_context(parent_ctx);