From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753051Ab0FLHfK (ORCPT ); Sat, 12 Jun 2010 03:35:10 -0400 Received: from mail-ww0-f46.google.com ([74.125.82.46]:65087 "EHLO mail-ww0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752877Ab0FLHfD (ORCPT ); Sat, 12 Jun 2010 03:35:03 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=from:to:cc:subject:date:message-id:x-mailer:x-mailer-version :in-reply-to:references; b=aQbzPDfdgIEovHfAh5beLDQbEhIRucafghnmHSfpxlOCttbGqHcHQtW+iYR1jeIv0W Ojo/zZAFw6SNplPkskkIfAbvJoTlQhxTMr7SlEWHZNlTKyfHwwziJtj9zgy/92tg7GKp 631kU14/AaHYDGp0nCMtll2znkU4c6QJGqsnA= From: Frederic Weisbecker To: LKML Cc: LKML , Frederic Weisbecker , Ingo Molnar , Peter Zijlstra , Arnaldo Carvalho de Melo , Paul Mackerras , Stephane Eranian , Cyrill Gorcunov , Zhang Yanmin , Steven Rostedt Subject: [PATCH 2/5] perf: Support disable() after stop() on software events Date: Sat, 12 Jun 2010 09:34:55 +0200 Message-Id: <1276328098-24114-3-git-send-regression-fweisbec@gmail.com> X-Mailer: git-send-regression X-Mailer-version: 0.1, "The maintainer couldn't reproduce after one week full time debugging" special version. In-Reply-To: <1276328098-24114-1-git-send-regression-fweisbec@gmail.com> References: <1276328098-24114-1-git-send-regression-fweisbec@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org If we call perf_event_stop() on a software event and then the disable() pmu callback on them after that, we'll call twice hlist_del_rcu() on the same hlist node and then bring a crash by dereferencing LIST_POISON2. Just use hlist_del_init_rcu() instead to fix this problem. This preparates for new context exclusions. Signed-off-by: Frederic Weisbecker Cc: Ingo Molnar Cc: Peter Zijlstra Cc: Arnaldo Carvalho de Melo Cc: Paul Mackerras Cc: Stephane Eranian Cc: Cyrill Gorcunov Cc: Zhang Yanmin Cc: Steven Rostedt --- kernel/perf_event.c | 2 +- kernel/trace/trace_event_perf.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/kernel/perf_event.c b/kernel/perf_event.c index 95a56ed..c5f2306 100644 --- a/kernel/perf_event.c +++ b/kernel/perf_event.c @@ -4292,7 +4292,7 @@ static int perf_swevent_enable(struct perf_event *event) static void perf_swevent_disable(struct perf_event *event) { - hlist_del_rcu(&event->hlist_entry); + hlist_del_init_rcu(&event->hlist_entry); } static void perf_swevent_void(struct perf_event *event) diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index 4799d70..7bc1f26 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -122,7 +122,7 @@ int perf_trace_enable(struct perf_event *p_event) void perf_trace_disable(struct perf_event *p_event) { - hlist_del_rcu(&p_event->hlist_entry); + hlist_del_init_rcu(&p_event->hlist_entry); } void perf_trace_destroy(struct perf_event *p_event) -- 1.6.2.3