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 63AE94E77F1; Thu, 17 Sep 2026 15:47:59 +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=1789660084; cv=none; b=qnIxzYtjNrT6vNW5vkrM+TMkXeaDrZ4Jabm30yTQELqRt/lZC9wkiGCakUjX9+klCL9/zdLUB1bJ4JBbNNdWQVIOROOULgqFqO+L9B6kQREsMSU3F5X0S2pVyJpt1tw5Lp2JSCloVfqDHLBzFqTG+rVRweP88mQ7kiunS4fyHyw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789660084; c=relaxed/simple; bh=ioRCnt2RvcabLGUE0TKsT/faIvjl63EWKwggeZqh0hQ=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=cDsIl20FkHXVvJj14EmdtKoaif0bKTxczWPLapj34Fb5bHcL0tBrDZOwI0GEB6N3ANJYKX4TYwEdVYRUiyMui2asEa81GRuJzX9xNq28e9GDEbdxBRY92Cx5nJgNJLZHPmgJosrn605T/d5GS6EXgzWdKIEtgStGangRekLFnv8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=ntYjv9LJ; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="ntYjv9LJ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 193FF1F000FF; Thu, 17 Sep 2026 15:47:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789660076; bh=e5RJP3u7CG8TdOABsYlWJw5Pu63RCzoXOCZLoGPXKnM=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ntYjv9LJaKBuOJm3/2njuB8GzZv5zyV87oylpk6WyjITK9klZBhs+6V6ehb4Dd3T5 Mjg/LbNAHZBD9uW/1x196EgGIFX0Kzx2g9oJiJAHlN911GlsDc0bsAcpQDHValLrqz Z4CZM28BYJBHSCs8wD3vEdvfjDyzVQjVkE8uUClk= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Donggeun Yoo , Steven Rostedt Subject: [PATCH 7.2 471/733] tracing: Set the trace clock before registering the histogram trigger Date: Thu, 17 Sep 2026 16:12:59 +0100 Message-ID: <20260917151403.726780399@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260917151350.597953846@linuxfoundation.org> References: <20260917151350.597953846@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 7.2-stable review patch. If anyone has any objections, please let me know. ------------------ From: Donggeun Yoo commit 6ede78d0563a2a3ae3e46f9c07cedb5d79645429 upstream. 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: Greg Kroah-Hartman --- kernel/trace/trace_events_hist.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -6631,12 +6631,6 @@ static int hist_register_trigger(char *g 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 *g 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);