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 C0B313C583B; Sat, 12 Sep 2026 15:58:36 +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=1789228718; cv=none; b=KsuR6pew56meKM75KQ1GeXT6nkSe3/dcWjR8mFFvDHx/h0t6Wz8XVeoOt7bJ+h1peTBuQLqQmWFw8WVLcW6Oh5OImKbwcgevE6mSgNU05N7YSIDIgrRPOQIyKT+GLNCybSt/7ziU5/aHyaZ8ldHzcyeX94upPhqkB8xCKV+soBs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1789228718; c=relaxed/simple; bh=GFQ9ywfm+1KhFSfu0w3W3SSllGJpGfapBbfzuUGXSDo=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=qKi8uUWGa2VqNLjcbBFhWHd+ODFEP4LIdn0zoMpA8IVyQy7F2MvFZiajIT0Oowa5TnA6Ii8KilTioDHvDQx2fzcC8WYpw9DFYbr429/Rsn+1DM7n09Lm4asUUugQcdKRyhne4sQg2XwKch3E+Mho6w2AZlWY40JNIty7yCXY7Ok= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=eyYg+V5f; 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="eyYg+V5f" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 3F4B81F000FF; Sat, 12 Sep 2026 15:58:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1789228716; bh=iuSwrfkbUmJUIU8T3jlN9hBB3lGx9SfGFcbyFwdqlZI=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=eyYg+V5fMi83BlCw7ixlO4xoHaugxKYXoiOo+R9iriB7zVSBqu85HPktaV3KFeU7H cKFYd+xw/XhZwBizxEGpXx7VxMQCfIveuU1mDtzmGUz6XWcCp2BW393WmMY1yZr4eq H3mgC8JgY7APooq4Ue5pECS34InG/P43vf5k3M3U= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Duoming Zhou , Simon Horman , Jakub Kicinski , Sasha Levin Subject: [PATCH 6.1 0442/1191] ax25: fix use-after-free bugs caused by ax25_ds_del_timer Date: Sat, 12 Sep 2026 08:52:50 +0200 Message-ID: <20260912065558.161833987@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260912065548.086904252@linuxfoundation.org> References: <20260912065548.086904252@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 6.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Duoming Zhou [ Upstream commit fd819ad3ecf6f3c232a06b27423ce9ed8c20da89 ] When the ax25 device is detaching, the ax25_dev_device_down() calls ax25_ds_del_timer() to cleanup the slave_timer. When the timer handler is running, the ax25_ds_del_timer() that calls del_timer() in it will return directly. As a result, the use-after-free bugs could happen, one of the scenarios is shown below: (Thread 1) | (Thread 2) | ax25_ds_timeout() ax25_dev_device_down() | ax25_ds_del_timer() | del_timer() | ax25_dev_put() //FREE | | ax25_dev-> //USE In order to mitigate bugs, when the device is detaching, use timer_shutdown_sync() to stop the timer. Fixes: 1da177e4c3f4 ("Linux-2.6.12-rc2") Signed-off-by: Duoming Zhou Reviewed-by: Simon Horman Link: https://lore.kernel.org/r/20240329015023.9223-1-duoming@zju.edu.cn Signed-off-by: Jakub Kicinski Signed-off-by: Sasha Levin --- net/ax25/ax25_dev.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/net/ax25/ax25_dev.c b/net/ax25/ax25_dev.c index 2b4f8df53b765..0715f9b152756 100644 --- a/net/ax25/ax25_dev.c +++ b/net/ax25/ax25_dev.c @@ -105,7 +105,7 @@ void ax25_dev_device_down(struct net_device *dev) spin_lock_bh(&ax25_dev_lock); #ifdef CONFIG_AX25_DAMA_SLAVE - ax25_ds_del_timer(ax25_dev); + timer_shutdown_sync(&ax25_dev->dama.slave_timer); #endif /* -- 2.53.0