From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792774265; b=drYtWS1KY4QrUkEvSr/x79XV5iXHu34AxcKOYBgNAD+4+RCh3lKMaSADWHzp66g10JhK 3sz0kyNfxNJ/wT4oVr3N0rw3iV+1Lucm3M5vUzn5jYH2aFLei/L6MP0B3sBSWajyRtHpk h8uFkcP4tZTVBiJpvp/YqryhQyANJSMLxs2Lq2ZU9ev71yYjXmoDk06hFDH7sA13YawUi l/nWL7wogzCcQDgXV+ipONdy/8shSYrH7MVyi/draBJz/1iT6TAfWSDV20NsX2x+Z0Aa0 BbRw7StO9b3K9CZo6jptDh9qn2jFMMXzUKEhVP5HJecIYlWb0OLAuPdLM6fOff+HWVA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792774265; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=aet5d1VpDMkqmg7sKAMBkyrnbqt1A5iiYmPdMcoduv8=; b=cBqReqr4kgXaOldbSvc9O6V+POT40YZOo7fTeqrPDGbC8W9gIpfxn0h1/WqeV7vrFKT5 JoG65m0G77ElhW1Lh1xbgQEu5GY47K7FdoQBxJSw8UsV6Gj7cn9MrvdT7yghnTHvmI6O6 CgweTKRM+U0Do7VTIdVaU4EO4aQqmCvTgeOGE6Xiolhtm2stDjbrH5PCKLaWE66rOp48c ixtXzhXBg0wNPCkZxmccPrWDi1BWyG6MB95o8OK6gafOwCGh4R0EhYnfSSfwCpFJumbzV e6H6vjOfT0Bui12WUMkde/kHHbVfL9QHbqV3BxI5rp1bb0RnTtASJJG4lwfdC4O/OXw== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=rzS206+F; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F105D606A324; Fri, 23 Oct 2026 16:51:04 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=rzS206+F Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4BF981F01825; Fri, 23 Oct 2026 16:51:04 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1792774264; bh=aet5d1VpDMkqmg7sKAMBkyrnbqt1A5iiYmPdMcoduv8=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=rzS206+F4T0/BwXAOO2g9ghrYHM3bft+MRxvANmAiSgwB+1xcYTegUCU9zrIUhNy6 O+IsHWupkcRX9z2HKGe7bAw1VgBqhCt9a7Wu9MRbO657d8xFHNre8iObuolJFLHxvY d7nKXB2SXXbeFyI3DnW7EAEeRgak4OLxBc8SN/34= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Donggeun Yoo , Steven Rostedt , Sasha Levin Subject: [PATCH 6.18 174/193] tracing: Fix NULL dereference when copying keys for a field variable Date: Fri, 23 Oct 2026 18:37:31 +0200 Message-ID: <20261023163718.334119226@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261023163714.201276352@linuxfoundation.org> References: <20261023163714.201276352@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Donggeun Yoo [ Upstream commit a0777b9e53157f1f6848a0fd0650f5465391ea81 ] In event_hist_trigger_parse() where it needs to create actions like "onmatch", it calls: event_hist_trigger_parse() { create_actions() { action_create() { trace_action_create() { trace_action_create_field_var() { create_field_var_hist() Where create_field_var_hist() does a loop on the hist_data representing the keys. The issue is, if the keys uses one of the pseudo field types (like common_cpu), the hist_data field element will have NULL for its field member causing a NULL pointer dereference when accessing the key_field->field->name. # echo 'hist:keys=common_cpu:ts0=common_timestamp.usecs' > \ events/sched/sched_waking/trigger # echo 'my_synth u64 lat; int prio' > synthetic_events # echo 'hist:keys=common_cpu:wakeup_lat=common_timestamp.usecs-$ts0:\ onmatch(sched.sched_waking).my_synth($wakeup_lat,prio)' > \ events/sched/sched_switch/trigger KASAN: null-ptr-deref in range [0x0000000000000010-0x0000000000000017] RIP: 0010:create_field_var_hist+0x771/0x1380 Call Trace: trace_action_create_field_var+0x360/0x600 trace_action_create+0x393/0xe80 event_hist_trigger_parse+0x3e47/0x69e0 trigger_process_regex+0x1a6/0x250 event_trigger_write+0xce/0x160 Instead of accessing it directly, use the proper handler expr_field_str() to get the name. The three previous patches are prerequisites: without them a .buckets key and a common_stacktrace key each render into a command that cannot be parsed back. Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20260914053443.981201-5-donggeunyoo.kernel@gmail.com Fixes: 02205a6752f2 ("tracing: Add support for 'field variables'") Signed-off-by: Donggeun Yoo Assisted-by: Claude:claude-fable-5 Signed-off-by: Steven Rostedt Signed-off-by: Sasha Levin Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_events_hist.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -3081,7 +3081,7 @@ create_field_var_hist(struct hist_trigge key_field = hist_data->fields[i]; if (!first) seq_buf_putc(&s, ','); - seq_buf_puts(&s, key_field->field->name); + expr_field_str(key_field, &s); first = false; }