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 4968B49BD99; Fri, 11 Sep 2026 18:16:17 +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=1789150582; cv=none; b=NnZOqJFl94aN7r3BP/6T2jQEe1+XjtKnitretgInstMZUkM646GNf7nDhFjxWaerjrYmyo7ThPXsY+Pw6/7yeV21apit+sJMAFvdWnAe7+SKJ9NH1FUF3jNe342zNIO1kNJdIEM1+HBjymuzK54fq+6Igkq7As8c4+3LBMT/0M0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789150582; c=relaxed/simple; bh=l7RMM3fOQcT67m9QVDy7NEUN0usrujTmJJ/b4bmuubA=; h=Message-ID:Date:From:To:Cc:Subject:References:MIME-Version: Content-Type; b=tMAafGgLgp6heW4JS66JJA2YkXwWJV0eQ9E8ou3+1XfYaqnPkJfOp7MInCp7Yq7KJDyQDxpHHAH23KMWCTk2fse4cz729DfBehJ0PJv0yFOs3s3zE8jX6gUlyb8GuIVXyIv/Pf1qZOeaAE6cnWTSdYDptZzlzkhz3rTFuHGU3GQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=bYBCW8St; 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="bYBCW8St" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3A8EA1F0089F; Fri, 11 Sep 2026 18:16:09 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789150569; bh=S0PII1y871JaHgR+bTBT4HW+/nC8mLPVa1/mhADxMxw=; h=Date:From:To:Cc:Subject:References; b=bYBCW8StGrvvtk4Z3GLT96eUDoomVYMvPN1NN22tQksUBXvFzlcCKk578Io1ksea8 MOnnj5mSx9NPqvqDzdx7Sb3bbJHYf0HKpWFoMHtPhX4XjNoNR6+MuVC6kAnATG3k+6 NFkth5q89iQWFz4d4B9LIyAKMlrbOFyewVWllPncPY8UK/B7lBJZc+J5QyrJ8yRNkx aGdzyzc+peciPhU2G8sUmjLrUeHR6a3lb+RAHjXrInzhvGlCSxsj8oGUW/PazsvnAN UeSs4johIOLuKAURpLxmBQ8zzlDozVX4n4FqX+G89q3XwKw8ZLaLP3gAmFzv381zRM 0fgYZAZaiQNlw== Received: from rostedt by gandalf with local (Exim 4.99.4) (envelope-from ) id 1x55oY-0000000951B-3R9D; Fri, 11 Sep 2026 14:17:30 -0400 Message-ID: <20260911181730.645121642@kernel.org> User-Agent: quilt/0.69 Date: Fri, 11 Sep 2026 14:16:48 -0400 From: Steven Rostedt To: linux-kernel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Mathieu Desnoyers , Andrew Morton , stable@vger.kernel.org, Donggeun Yoo Subject: [for-linus][PATCH 12/20] tracing: Set the trace clock before registering the histogram trigger References: <20260911181636.485043797@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 From: Donggeun Yoo 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 --- 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 5e00da2d5b1a..1889e310b73c 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -6631,12 +6631,6 @@ 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; @@ -6649,6 +6643,15 @@ 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