From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D123E4B829B for ; Wed, 16 Sep 2026 16:48:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789577348; cv=none; b=DijLrIHo6bk5cxAc1qj1vRVoLP2wlALXq7efZb8P+4AODgOH0mXsmr09PPOclSIQvk8FoZ1AKelYneiRISOFaJUrioR4Oi7pgsnPwgO+Bux76/8yMONWiBWjB9mQ7ofunLJ+kFfS2VQEdRiPxxBiltd2RJ268v+smU01n+yB2SA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789577348; c=relaxed/simple; bh=aKkhna3O+GtdNCBdQ+eKksQP0Jx3xSXj3EfHh4AckvM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=CCaGY8gwhqA+aC3JOhfAVdSDu36zTIXsClYFmLls2tqw2FezYMG6w0YdZWXuD0zJhlLDQiijgSCumR9VenN/IjP0x8a0rSt1xkdFERbqDsk+c7wXnycA1Vzndli5zQzF462Ric6FxD1hMaiU2Xc5hY86Ve8jObGO7VNCfc6ggIk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=k+yYDOoT; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="k+yYDOoT" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4F8891F008A0; Wed, 16 Sep 2026 16:48:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789577337; bh=k6tbjnWrRhM52F1OhbO7KukYPiuMgblmb4b+o7ClZa4=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=k+yYDOoTCLdV+ARSkgVf5rT/NvUkSSXHXCRMsABQybsne0G4+yuWPix+eajF74xGb sCnj5LrRAIq3suFtJkKZaS/Np1mv0n8EJJAvap5gtZ6NNK6ORcCWV6kGFlbQBpb0to EWtVGnu442TazwGXtpFfNmdfWWSNHKEc+wxhUZkpMeGbWfMAmoNlu/aX6I6PEiD/5A ZQKjT6EfV+DeRjJllz+T4O6m57ImCfbyYt5XG0yHrLZZIz4PYEjSYya88CMUMusuKK oNJQ1jK1revqRTwhBIrZC4xmSh4A84EJkXh+Bdm+3PgdzE/Em9QdxI9E/VUCY/LnKp 76mZ0vkxVBDAg== From: Sasha Levin To: stable@vger.kernel.org Cc: Donggeun Yoo , Steven Rostedt , Sasha Levin Subject: [PATCH 6.6.y 3/3] tracing: Set the trace clock before registering the histogram trigger Date: Wed, 16 Sep 2026 12:48:53 -0400 Message-ID: <20260916164854.543620-3-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260916164854.543620-1-sashal@kernel.org> References: <2026091626-postnasal-annotate-b622@gregkh> <20260916164854.543620-1-sashal@kernel.org> Precedence: bulk X-Mailing-List: stable@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit From: Donggeun Yoo [ Upstream commit 6ede78d0563a2a3ae3e46f9c07cedb5d79645429 ] hist_register_trigger() puts the trigger on the global named_triggers list in cmd_ops->init(), and only then sets the trace clock: if (data->cmd_ops->init) { ret = data->cmd_ops->init(data); if (ret < 0) goto out; } if (hist_data->enable_timestamps) { ret = tracing_set_clock(file->tr, hist_data->attrs->clock); if (ret) { hist_err(tr, HIST_ERR_SET_CLOCK_FAIL, errpos(clock)); goto out; } The clock string is not checked anywhere before that call, so a named trigger using common_timestamp with an unknown clock fails after it has already become findable. event_hist_trigger_parse() then frees it without taking it off the list, and the next lookup by name reads the freed object: ~# cd /sys/kernel/tracing/events/sched/sched_switch ~# echo 'hist:name=foo:keys=common_pid:ts=common_timestamp:clock=bogus' > trigger bash: echo: write error: Invalid argument ~# echo 'hist:name=foo:keys=common_pid' > trigger BUG: KASAN: slab-use-after-free in find_named_trigger+0xac/0xc0 Read of size 8 at addr ffff88800915d760 by task init/1 find_named_trigger+0xac/0xc0 hist_register_trigger+0xc1/0x900 event_hist_trigger_parse+0x3146/0x6af0 event_trigger_write+0xce/0x160 Freed by task 63: kfree+0x154/0x420 trigger_kthread_fn+0xfd/0x160 Set the clock before the trigger is registered, so that nothing which can fail runs after it is published, the way commit 6f86bdeab633 ("tracing: Fix bad hist from corrupting named_triggers list") moved the registration below the rest of the setup. tracing_set_filter_buffering() is reference counted, so the init failure path has to drop the reference that the clock block now takes first. Cc: stable@vger.kernel.org Fixes: a4072fe85ba3 ("tracing: Add a clock attribute for hist triggers") Link: https://patch.msgid.link/20260907091415.554535-1-donggeunyoo.kernel@gmail.com Signed-off-by: Donggeun Yoo Signed-off-by: Steven Rostedt Signed-off-by: Sasha Levin --- kernel/trace/trace_events_hist.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 08e1027a16b0a..e13ee10d2b2a9 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -6567,12 +6567,6 @@ static int hist_register_trigger(char *glob, data->cmd_ops = cmd_ops; } - if (data->cmd_ops->init) { - ret = data->cmd_ops->init(data); - if (ret < 0) - goto out; - } - if (hist_data->enable_timestamps) { char *clock = hist_data->attrs->clock; @@ -6585,6 +6579,15 @@ static int hist_register_trigger(char *glob, tracing_set_filter_buffering(file->tr, true); } + if (data->cmd_ops->init) { + ret = data->cmd_ops->init(data); + if (ret < 0) { + if (hist_data->enable_timestamps) + tracing_set_filter_buffering(file->tr, false); + goto out; + } + } + if (named_data) { remove_hist_vars(hist_data); destroy_hist_data(hist_data); -- 2.53.0