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 E0BBB3C7691; Wed, 23 Sep 2026 14:42:47 +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=1790174569; cv=none; b=rmD+mvghqDxUQ3aevu/xAq4Q5xZPH2iU4E6qbEAabEj+CrwchwMDv7GtMud1oNEFI3uVfAKdy2DsmwCq4k91C0V6hV7gaTJ7Gpt78yLcdMMgwhW1oYbTkNnIxwGmnlmIrH33YRN1jRfc8pijmA5IWCZrKDYvYoyVF+vMWSdR0WY= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1790174569; c=relaxed/simple; bh=SAonyX/CAvgixc1zNHRtxB/ssDfjYlEdn6HZE8YEH4U=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=c3F6Tae+GeBScBdEjHqB6NBUnrl0K21mffi8ODPsxdK+CrjjpNDngEDfv/02aXyZmpGw79K0h+2V2NOZuwJ+mrPCTp6dEi9GNw6YtasRpCJ9sA/3byh8Z7w94j7lV1TtAn1kTTwcDWpn5ANw6iZEdb9zJllEFrackv9/SP2ShR8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=HmlxdCjx; 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="HmlxdCjx" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F1F551F000FF; Wed, 23 Sep 2026 14:42:46 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1790174567; bh=MZBGErDIjEHhWruy6eSXNIq2r+Mg7k9x/CzLNWzWBrU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=HmlxdCjxUMlHePyGuAQ805gapF68XWZ6M/57LGQTux8p4KpQo7ewwPlw1bVIoF1ea DpqaRwBMJtuMQZemX2Bd469Z+3bzE7qgWEsU955UQJP/WVwvqAsiEtwCqlEaUXmYTd NdAuNHKstN+RIY+TB8YQmEGr4VjR1XT4fHKspi8g= 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 6.18 156/398] drop_monitor: synchronize tracepoint unregistration on error path Date: Wed, 23 Sep 2026 16:03:50 +0200 Message-ID: <20260923140647.480838290@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260923140643.441954610@linuxfoundation.org> References: <20260923140643.441954610@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 6.18-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 a5e75cd04d6ca..172fd2dcbfe93 100644 --- a/net/core/drop_monitor.c +++ b/net/core/drop_monitor.c @@ -1174,6 +1174,7 @@ 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