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=1792673700; b=LCIY7zSd2rR2m9JS//XiJNMQv0cBnbF0S4u6d7buQ+rgdso0eU8eUY14S5ATtvI6+OlL GP3WlWfrNQ6oAzWCuMzxCGm58NeLyhml4JluFel7H9iFGFnD5ozmTptWQobxyz4YmLBu+ 9hIjgzbWpY4b38UDEcFVWBi7wOfoQOpiiUawA+y5VtlNR6XB8fR8kOS7UHUiPvsvB27ZE fd1Ye3TJ47B+QZm+tcgjFnB0iJGsYZUBOj46n7feHKY7dxNxZ82gj0pQK8OwfZckAbSG/ nm0v5BOl+guPe+fWmrycsXGWPDqolhALS+zJDuYEPoTVGJ2uxwvEoEEmgmVsSHXAdRg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792673700; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:MIME-Version:Content-Transfer-Encoding; bh=ut596dSYDA9muKlngf95bMEANj8c9d53sp5+5NOhEJk=; b=maDULup1aZ6/uo+D6Ar8ZT75wOeO5t9TT+kQFz5utQVGTw44m60Z8UhFk4yXFKG8Y3O+ svRaneRRvigNiVasdi26zd/uTwa+DDB2Y83x5Z/zsB08ZSp/QaLHKYAqkQOtleZVigm7U kUodAol/k7inzD3zbBK57VKsD3kNiTEDA2ILRG5oFXivqnAVo6YpK2RoYkhPh3jetoDQJ 4RdgsXUhdiNxlDkEtuwAeA6ykUwXRe3rw+RqmsRL0mVfRT96xRLbXd9fV8EfVFhCt7T72 +vh+cR+7xQ6ZQDuYykZLXplUxOXNW8PV/tpqMVBObDmvUY86BirezYPjhGWcu1p1EzA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=FFj3uWnG; 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 DAA9B606A323 for ; Thu, 22 Oct 2026 12:54:59 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=FFj3uWnG Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3B0B01F000C1; Thu, 22 Oct 2026 12:54:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792673699; bh=ut596dSYDA9muKlngf95bMEANj8c9d53sp5+5NOhEJk=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=FFj3uWnGvN211ipES/YXsjnTdTPT7CWdqMof+SAHAvKdXhgtQAZuYGj6r2kuuk7NR UV2lk4ImjksqChlZpI+x5brNGpQzULl5AKyGxMZb0IeEwZdaCZWgn8nVCiQO59I/0n SYW2jOWrxHW+DIslEuQmOKtq3xExWAp2o8O8uudZzQljQRw8LNAcqoQ3vl2ILguZ5/ ttny9PMJP44M0pPQFWaNfIG+ZHZFIa4rh7BzN2835QQ/Zmt89Wc6BizERMd1fl+kHg 1cnUlwnlrQZGB3/sT0Ud6kPirw2bEzHAFxzMpVGx1ooyc6sqV5OKofZEk1s0x7wx1Y 04DbUTPRF9gZA== From: Sasha Levin To: stable@vger.kernel.org Cc: Donggeun Yoo , Steven Rostedt , Sasha Levin Subject: [PATCH 7.2.y 3/3] tracing: Fix NULL dereference when copying keys for a field variable Date: Thu, 22 Oct 2026 08:54:56 -0400 Message-ID: <20261022125436.1346436-3-sashal@kernel.org> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20261022125436.1346436-1-sashal@kernel.org> References: <2026102121-bronchial-ozone-0317@gregkh> <20261022125436.1346436-1-sashal@kernel.org> X-Mailing-List: stable@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 8caeb6bfb7d5e..2295ca7bccefd 100644 --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -3078,7 +3078,7 @@ 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