From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (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 E67D03E00A1; Wed, 30 Sep 2026 19:24:35 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790796277; cv=none; b=eQ0pixXMMktFaRGLIDvJQtJ+/DFTjzBZ5daALcB5ZFltAU3XmfMlXwjnRzOQLRpP1pR7XZcrRxY765PwijNIq2vvmb2sKYwX9Msnpk4VqHC1M/dGkgQHAHV4G9b6db5JZIpJeWoaJ4U/NQQm4L5IEoYz3MF865kU9LDvmfs3HJ4= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790796277; c=relaxed/simple; bh=n0gRjuMr8z6sTJlmTYJoUbN379J8vlFATqOs3bJu87c=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=onp34v1Xn5zESSGa0mfOh8AJL47P4by0o4qDTqrEwOwdlWLGxtsY3nNhJgZZQ/I5dVPvNHJKxwrVxLH6ISvodemBkejITg2fm+tCmreatK3uZNjtw8adxFrhHMcmxlvo80z0cBguX0aUnIAujkAx3AvpaDqxvHcmysouv8ylJrY= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=BkWwlkym; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="BkWwlkym" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4CF5E1F000FF; Wed, 30 Sep 2026 19:24:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790796275; bh=uBVlQZxdi9CTevxIuuAfAU30DeYxKqO5E6DhULEmdXA=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=BkWwlkym0+4VrWqIpBpBzDtWkp6a0yBQ6VGbaLjYtWEUsJ2wkaEjlowaSm/I4t8vn FnIpODMnTVyYuzxWqRsFLrY72KyN+NIEfW6PqB0s5Y9LmKEV3u2ut/CHMUfa9cpL7i 3nudJIsQZsmrJVFX50OjyhTX0kj7zA525M2OW20o= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Eric Dumazet , Hangbin Liu , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.6 0811/1193] drop_monitor: synchronize tracepoint unregistration on error path Date: Wed, 30 Sep 2026 17:24:55 +0200 Message-ID: <20260930152452.263969967@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260930152434.301151190@linuxfoundation.org> References: <20260930152434.301151190@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.6-stable review patch. If anyone has any objections, please let me know. ------------------ From: Eric Dumazet [ Upstream commit 6a038ef2b57922b6d9ca98ddac0df0681849b704 ] If register_trace_napi_poll() fails in net_dm_trace_on_set(), unregister_trace_kfree_skb() is called to roll back the kfree_skb tracepoint registration. However, tracepoint_synchronize_unregister() is omitted before calling cancel_work_sync() and module_put(). An in-flight probe executing concurrently on another CPU could call schedule_work() after cancel_work_sync() has already returned, leaving a pending work item scheduled after the module reference is dropped. If the module is then unloaded, executing the work item triggers a kernel panic. Add tracepoint_synchronize_unregister() after unregister_trace_kfree_skb() in the error path, matching net_dm_trace_off_set() and net_dm_hw_probe_unregister(). Fixes: 7c747838a558 ("drop_monitor: Split tracing enable / disable to different functions") Signed-off-by: Eric Dumazet Reviewed-by: Hangbin Liu Link: https://patch.msgid.link/20260910204612.3762015-2-edumazet@google.com Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/core/drop_monitor.c | 1 + 1 file changed, 1 insertion(+) diff --git a/net/core/drop_monitor.c b/net/core/drop_monitor.c index 60ca18b440a34..052abd988e80a 100644 --- a/net/core/drop_monitor.c +++ b/net/core/drop_monitor.c @@ -1171,6 +1171,7 @@ static int net_dm_trace_on_set(struct netlink_ext_ack *extack) err_unregister_trace: unregister_trace_kfree_skb(ops->kfree_skb_probe, NULL); + tracepoint_synchronize_unregister(); err_module_put: for_each_possible_cpu(cpu) { struct per_cpu_dm_data *data = &per_cpu(dm_cpu_data, cpu); -- 2.53.0