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=1793209762; b=B1TAv0LbiTp9XRO/lN/WbB3e/f/wSpWhqoaWz7fubATKs89ZJvhKvh5xLhoBqa9cp3Lr DkvuHCptYU6uvucabysN8NOUXOcXeVujA4+olLBG2JNK2CCNRUx6xOlterHl4DYR9Pxx6 sQ87z+hvKa4msQG6/5XSaCTLbTBGOOlB38fNzVW/agfqoIAsuFXmKz2biZ2CfjCQDEnwO YB5PQJ9iSwYanzVNnO9Z2loUx2woHxb+y29ZX+WGklErPeXp/l9SsosQufiRx/ji0fc4A 4qYpXtX972GT1HQprdVXE9vgJMxs3hAXNLo60DO7iHrqWKZ8yAkq0f1HVR1i3IsghYw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793209762; 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=/SQIFnu3KeTgUxUljYST3aqaOMlp8x94FFO8VmqgWng=; b=Hwa/cj3g+oZXBInxIpU6MV+DYw3KydRV08VksFfwUlEysfEQaB5P9ACYisPVLuzf5kMp dfcYcwoWGydLBCeVnszAbbXx9gv6CTVuviCJeMRMKwTjBzHNifO8b3wg++PNTZIZeS1dM fEnKv5nY8KZsqJRvLJByuyIUGuGEdc4zv2WYPYF6XGzjHFRZA+AhZ5BteId4q6RldYrkv HzB/zWkz2XgXUCaCpYRdsDfVL1dBCYrFuZbjc0/i0A6ZOzgLFZ3X2GI+6fpgOgTrZfdTw m/vOf+UeN9gn+FOg34+2L1ndscO+3GDmomxECoQejNifXXko+n+s9rp3Da2PQFcx5Tw== 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=C6qTdwzQ; 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 53580606A31A; Wed, 28 Oct 2026 17:49:22 +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=C6qTdwzQ Received: by smtp.kernel.org (Postfix) with ESMTPSA id A28121F01829; Wed, 28 Oct 2026 17:49:21 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793209762; bh=/SQIFnu3KeTgUxUljYST3aqaOMlp8x94FFO8VmqgWng=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=C6qTdwzQHll9PPFho+MlDYGjZw/dhzFYbF6LhXRoLFi4rcwdg38Lq2K/tF/ldjpjC pKVRzdPX0XZcfyGIW4Pc2P14Mn3DwPD0pjB2r/JjyMTElQgP5Gf67yG6csZWVoLKZy Fg7+Pw7vxQQEKqqLINDTw1KzeqP/065bNwAWdQnQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Lee Jones , Steven Rostedt Subject: [PATCH 6.18 041/109] tracing/histograms: Verify event_call identity when updating synth_event refcount Date: Wed, 28 Oct 2026 18:00:25 +0100 Message-ID: <20261028165943.329329818@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028165942.357251485@linuxfoundation.org> References: <20261028165942.357251485@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: Lee Jones commit 3403d9bb27ebc3572bd048620746b4414e073bf9 upstream. In event_hist_trigger_parse() and hist_unreg_all(), the histogram registration and unregistration paths look up find_synth_event() using trace_event_name(file->event_call) and adjust se->ref if a match is found. Because find_synth_event() only compares the event basename, registering or removing a histogram on a non-synthetic trace event whose basename matches a synthetic event erroneously modifies the synthetic event's reference count. If a histogram is registered on the non-synthetic event before the synthetic event is created and removed afterwards, se->ref is decremented without a matching increment, allowing the synthetic event to be freed while an active histogram action still holds a pointer to it. Introduce find_synth_event_call() to verify that &se->call matches file->event_call before adjusting se->ref. Fixes: 4b147936fa50 ("tracing: Add support for 'synthetic' events") Cc: stable@vger.kernel.org Link: https://patch.msgid.link/20261019120730.2342739-1-lee@kernel.org Signed-off-by: Lee Jones Signed-off-by: Steven Rostedt Signed-off-by: Greg Kroah-Hartman --- kernel/trace/trace_events_hist.c | 11 +++-------- kernel/trace/trace_events_synth.c | 10 ++++++++++ kernel/trace/trace_synth.h | 1 + 3 files changed, 14 insertions(+), 8 deletions(-) --- a/kernel/trace/trace_events_hist.c +++ b/kernel/trace/trace_events_hist.c @@ -6753,7 +6753,6 @@ static void hist_unreg_all(struct trace_ struct event_trigger_data *test, *n; struct hist_trigger_data *hist_data; struct synth_event *se; - const char *se_name; lockdep_assert_held(&event_mutex); @@ -6766,8 +6765,7 @@ static void hist_unreg_all(struct trace_ list_del_rcu(&test->list); trace_event_trigger_enable_disable(file, 0); - se_name = trace_event_name(file->event_call); - se = find_synth_event(se_name); + se = find_synth_event_call(file->event_call); if (se) se->ref--; @@ -6791,7 +6789,6 @@ static int event_hist_trigger_parse(stru struct hist_trigger_data *hist_data; char *param, *filter, *p, *start; struct synth_event *se; - const char *se_name; bool remove; int ret = 0; @@ -6885,8 +6882,7 @@ static int event_hist_trigger_parse(stru } event_trigger_unregister(cmd_ops, file, glob+1, trigger_data); - se_name = trace_event_name(file->event_call); - se = find_synth_event(se_name); + se = find_synth_event_call(file->event_call); if (se) se->ref--; ret = 0; @@ -6921,8 +6917,7 @@ static int event_hist_trigger_parse(stru if (ret) goto out_unreg; - se_name = trace_event_name(file->event_call); - se = find_synth_event(se_name); + se = find_synth_event_call(file->event_call); if (se) se->ref++; out: --- a/kernel/trace/trace_events_synth.c +++ b/kernel/trace/trace_events_synth.c @@ -848,6 +848,16 @@ struct synth_event *find_synth_event(con return NULL; } +struct synth_event *find_synth_event_call(struct trace_event_call *call) +{ + struct synth_event *se; + const char *name; + + name = trace_event_name(call); + se = find_synth_event(name); + return se && &se->call == call ? se : NULL; +} + static struct trace_event_fields synth_event_fields_array[] = { { .type = TRACE_FUNCTION_TYPE, .define_fields = synth_event_define_fields }, --- a/kernel/trace/trace_synth.h +++ b/kernel/trace/trace_synth.h @@ -37,5 +37,6 @@ struct synth_event { }; extern struct synth_event *find_synth_event(const char *name); +extern struct synth_event *find_synth_event_call(struct trace_event_call *call); #endif /* __TRACE_SYNTH_H */