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=1793210238; b=sRitqukjsXqjkZ7wke93QJIuOLUxAb8DYWqwhi2CAf6Wb9eEbW7hwLWPSnlDEYbC+rV9 bCtpV+eNw8C9Gu9tD2B1PJpshveO4cCfRbvvHMyWt0mnmMpPMlUcZU1mqSKv8V564D9S7 8uDrtR1BaRJTWlyFLQj6O991mCH5fBxDdF/c0V7euYH60V8FfKI2wSRNzxkfJaQmJtNgF ITtuxFULEot0MWnBdnJxc0y/t/A7qvkr6xSxnLLN1cVmz7PnbgNBP+Iro8mEXep0LXPAx mPC6N1eTbiCosd6rN9Q6lrRe+AFTVgtkHhtJPPfskSVvILA1YK7HFnRSUO4QjWLk8cA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793210238; 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=oQOrLtGcZuctPcVHg3Waqh5NHTDQ22hej/4FgnK827E=; b=eqX8DrviuiBZJvcNscfPVcdJD4zb1SZdnEhORXsHDByrEKPAOpide2p1T/SGOiPJqq3z nG/2hSjTj1EI8wDp01UhHnFlY2xHIFHSN23rQML7A3ejMxsLmNRq4J4CNC4GvbI3L5dFW m3CUn7GH7eMguuGgIdgjbm4+wwDS/eBoLm49127eMhEdECDGOHq0FsR48JSAS++Dz6NUK JmFI5UJ/i0xu242txY9LEG/n9y/SanR0jqCCy8EOx5eZnkW299o/tNXMoqmk/eJSKCiyg apfjKNJC6z5E7sdjB3j0gFzaObzSDw6K61ShQl2HgDnwRYliN62/QmPJzuMI7bHo6Dg== 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="UdLs/Ww5"; 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 8548B606A31C; Wed, 28 Oct 2026 17:57:18 +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=UdLs/Ww5 Received: by smtp.kernel.org (Postfix) with ESMTPSA id D62A61F01828; Wed, 28 Oct 2026 17:57:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793210238; bh=oQOrLtGcZuctPcVHg3Waqh5NHTDQ22hej/4FgnK827E=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=UdLs/Ww5iTaw92BCNjrbTjn7kPfUb5tuBZ/URP3UMXsUAclrnwREIamnr9X/qozQH AsLy/7lj15o54or7xJK1eNKuei3Bm+GlT3qqXiJJfA8yVHiTSofA7mHx2CDAdrwFj0 /uuC+rG/JffcJyZV/58TRQQlynWt7J1odKp39VRM= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Lee Jones , Steven Rostedt Subject: [PATCH 6.6 125/168] tracing/histograms: Verify event_call identity when updating synth_event refcount Date: Wed, 28 Oct 2026 18:01:01 +0100 Message-ID: <20261028165946.045200782@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028165943.089486480@linuxfoundation.org> References: <20261028165943.089486480@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 6.6-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 @@ -6729,7 +6729,6 @@ 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); @@ -6742,8 +6741,7 @@ 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--; @@ -6767,7 +6765,6 @@ 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; @@ -6861,8 +6858,7 @@ 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; @@ -6897,8 +6893,7 @@ 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 @@ -857,6 +857,16 @@ 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 */