From nobody Fri Jul 24 20:48:51 2026 Received: from relay.hostedemail.com (smtprelay0013.hostedemail.com [216.40.44.13]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id ED61543CEE7; Fri, 24 Jul 2026 17:23:53 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=216.40.44.13 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784913836; cv=none; b=ZP76FkI6yeJ2O1QOlCGg1KSR0+W/UVlDknOlassyQ/oz/ZxwkTNbjKW8YYudEBql5pPVr3pNSbOS+qN6v6l4iQKDzuo0hLmbFGXJp2DGdl24l8lyCCaYAN6hwqCcf53929WcQAnLJctUxrhExV/H4bhPf4VXFTV1xbyxmAnHRNs= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784913836; c=relaxed/simple; bh=kFTB3zM2liSxnFOeyMCY9Avdx8ZrP0mW0fYyZEZ1K9c=; h=Date:From:To:Cc:Subject:Message-ID:MIME-Version:Content-Type; b=Yb299Heegsk4eHABFP0Pvu/i5ChYagldnsYUgT0443VTPiw8Ni11DSjkgrnpjZgo2AYWM20pdPU8fNqUNbJrCzilsVgVbRUPHRHCqh3xzt6h+RDeJx+24tY1ceqaOUR+LjM98Szrt+zrdbWrFq0FlWd730R7a+jJG3gmGsdRT8o= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org; spf=pass smtp.mailfrom=goodmis.org; arc=none smtp.client-ip=216.40.44.13 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=goodmis.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=goodmis.org Received: from omf05.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay05.hostedemail.com (Postfix) with ESMTP id 88615402FE; Fri, 24 Jul 2026 17:23:52 +0000 (UTC) Received: from [HIDDEN] (Authenticated sender: rostedt@goodmis.org) by omf05.hostedemail.com (Postfix) with ESMTPA id 0642A2000E; Fri, 24 Jul 2026 17:23:50 +0000 (UTC) Date: Fri, 24 Jul 2026 13:24:15 -0400 From: Steven Rostedt To: LKML , Linux Trace Kernel Cc: Masami Hiramatsu , Mathieu Desnoyers Subject: [PATCH] tracing: Delay module ref count for "enable_event" trigger Message-ID: <20260724132415.1b5005db@gandalf.local.home> X-Mailer: Claws Mail 3.20.0git84 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-Rspamd-Queue-Id: 0642A2000E X-Stat-Signature: i7ybatrkwx3codoa4cja3zja165bo994 X-Rspamd-Server: rspamout07 X-Session-Marker: 726F737465647440676F6F646D69732E6F7267 X-Session-ID: U2FsdGVkX1+lJLUje1q5HJrwQa6NG1hROELO+yXUFBQ= X-HE-Tag: 1784913830-132034 X-HE-Meta: U2FsdGVkX1/KchazAR5R6yhpXVB1Zboe+M2Z8eXYPETqG2m4pZmLm5tA8s1O+Op02P/Gq9BQitj7dS7ZDU0XWIaD98IodgA1XY/Wt+xULNTCpDBZqt4X9icIZ2MvwTdTQFEbyHkII8hQXO5AeIvhZ5/YZgTFlOD62J5QMc6pEote+8u4YYXosRIfAZG+TQUDHDA1vPW02Mx1imGiCFTDrD0en4Lt82eAsbBzEZQIfRZ/l+eVOkwgCerx4EUoqAJYOE3ste4LvJfg8CCkEwZxMe3g0Qq1TYWzhFoWhCG3XGcFW04LuNa2Pq7paeT42Z4V6AB7NQaB6YdHvM0iszrbHFj4RGWJ2CL3QMA7YjGBAudAqqvDcfF8jW2AN76wYStd+dboH8Z+uCKuWeVlljUVO9K5KbIW4ihLKyNjYeSqkNev7TN7hvdoT2RdGbrYXs3JJ/2QttnT66EjV4oMN/qetGUJZhz+6MDXdL2YZ2apOzg= Content-Type: text/plain; charset="utf-8" From: Steven Rostedt Triggers are now delayed from freeing, but can still be triggered until after the RCU grace period has ended. The freeing of the enable_event data is put into the private_data_free() callback, but the put of the module refcount is done immediately. It is possible that if a module is removed that has an event that would enable (or disable) it is still active, it can read the data of the module after it is removed causing a use-after-free bug. Move the trace_event_put_ref() that releases the module into the delayed callback so that the module can not be removed until any reference to its events are finished. Cc: stable@vger.kernel.org Reported-by: sashiko-bot@kernel.org Link: https://sashiko.dev/#/patchset/20260724030523.19081-1-devnexen%40gmai= l.com Signed-off-by: Steven Rostedt --- kernel/trace/trace_events_trigger.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) diff --git a/kernel/trace/trace_events_trigger.c b/kernel/trace/trace_event= s_trigger.c index 46e60b70a4bb..ad83419cb420 100644 --- a/kernel/trace/trace_events_trigger.c +++ b/kernel/trace/trace_events_trigger.c @@ -1726,7 +1726,10 @@ int event_enable_trigger_print(struct seq_file *m, =20 static void enable_trigger_private_data_free(struct event_trigger_data *da= ta) { - kfree(data->private_data); + struct enable_trigger_data *enable_data =3D data->private_data; + + trace_event_put_ref(enable_data->file->event_call); + kfree(enable_data); } =20 void event_enable_trigger_free(struct event_trigger_data *data) @@ -1741,7 +1744,6 @@ void event_enable_trigger_free(struct event_trigger_d= ata *data) /* Remove the SOFT_MODE flag */ trace_event_enable_disable(enable_data->file, 0, 1); data->private_data_free =3D enable_trigger_private_data_free; - trace_event_put_ref(enable_data->file->event_call); trigger_data_free(data); } } --=20 2.53.0