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=1793831306; b=g1OXzL3wUH1nM34xqgUJKTHwxzV1lSCSx4FJWT3zCbXspbylvhYWqXgNQpabhUyYMroE IaRMXV9iCMlBaomy6WQHQxgKA+vqLZ0jfYhT4kYDkl7xPxvTByuAXqquv1il/w94Y3/Nw grvHr7HVk01jJOhZekEDA73V/taoeC1LRhn5pSLedH56jXpa2qEwlZnJp56RnEQhC0xiw R70H0R/ApYvnNN0IP3Ae0Uns+FKXhEbzxOUxM3d9vxp0mXlMh9A6eLqRJMefV3Wo7RP1c s2EQpVMC3LcFPUtLR3sPKrGiBrFnosBs/8Wc/wvO5iAhFNPf9pEpwTFGvJ+4Pz0kzAg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793831306; 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=iEoqogTst20l3WKmgX3/Lv++A1v7goWln2eSe9KiP1k=; b=TyoChQwRNb5XvKW7+LDZtyQV9DHufGF8EkX81uPWslxUYomOmeCofz4nwYcEDvs0BLxW D0KmVyI7nsnUVOAbRn98OkxWjk7BGOAXwgYE2vcQLgVj/1BAOcRmPssUzEXb7X07cnsjN WvSmtbNHk59ZCMqES+RX67Rh6AzjrxAWbzY3HEwx1RAw74TaqYw8/eQd6/bvqRoFke/um mzqcTDOls/WVvjg6feib+NGAH+RyG4Mme/S0JgdPw1YYrlg8AyBh7N1qhYstAzuurWA05 COP/MqdDgCvR9L8yjl0Ab8sCitlA/2zRV22dDPPgQ4oDl0S83+qQK4SdYgQsmQmA0vw== 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=1Fb7N7zu; 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 BE1EF606B2F8; Wed, 4 Nov 2026 22:28:25 +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=1Fb7N7zu Received: by smtp.kernel.org (Postfix) with ESMTPSA id 52E211F000C1; Wed, 4 Nov 2026 22:28:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793831305; bh=iEoqogTst20l3WKmgX3/Lv++A1v7goWln2eSe9KiP1k=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=1Fb7N7zutAp8zwa01YiP5rlwap1njJFl8ceqWC7j3aisF78LNdboFOW7lh+0xM4PF iT6Hei3GZp6xAS368jX/wIU/pnXAom6E4SbrPn9UbZTVzgdLgEyIunJarQHEowF8b8 Cn4CjSwYiMfc848OoRJsK/XBuWvHZUc3nyUCkukY= 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 0622/1005] tracing: Fix NULL dereference when copying keys for a field variable Date: Wed, 4 Nov 2026 16:05:55 -0500 Message-ID: <20261104211101.236551980@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261104211043.516122098@linuxfoundation.org> References: <20261104211043.516122098@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 --- kernel/trace/trace_events_hist.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/kernel/trace/trace_events_hist.c b/kernel/trace/trace_events_hist.c index 086a996c945b4..882e10e776fe4 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -3096,7 +3096,7 @@ create_field_var_hist(struct hist_trigger_data *target_hist_data, 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; } -- 2.53.0