From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp153-165.sina.com.cn (smtp153-165.sina.com.cn [61.135.153.165]) (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 CEE9B3054F9 for ; Fri, 23 Jan 2026 10:26:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=61.135.153.165 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769164005; cv=none; b=bIKaFGxzNQKYXatqT/YL99TRs/RHk6Q1qfOe6KyHoya2Q8Te8/8v2UO0iFiN6n4uIPDJC58CbOCvceYkILn81gxLsck6qMaqwzgruQbVyEyvSJCjv8aoLZ0HcUwucaoc33b2zZjxXXzFpDcvomTDmBZJlMX7CYznTk3/NDjoXJs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769164005; c=relaxed/simple; bh=IKHkqsLJlbs6PCf6tikVWwQVfHa5UB97Oi3Tehx6glM=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=lJNcuPyVrIafLka+G8nyb56ewD4f5Zzh+4EQ18OZWZzsjdbHNM25iXpX00eh/G+SgWgDjoaSjMziDKCFhPH3d3tgsEK6cbPE+bhMudO1u236mGFvw89BbjcWJTgnk9dHGKrJjPHW800HvaBERc2qtdOEpi/J6nskCkwd+CYVsgk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com; spf=pass smtp.mailfrom=sina.com; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b=wV2M3Scl; arc=none smtp.client-ip=61.135.153.165 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=sina.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=sina.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=sina.com header.i=@sina.com header.b="wV2M3Scl" DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=sina.com; s=201208; t=1769163999; bh=IxugXp4SjSpX8+tZYIMfRrJ6ADhcuk5hc/Bone+7pYw=; h=From:Subject:Date:Message-ID; b=wV2M3Scl69S/mug1807Quw9p4ZUJnb1Bbg6brs27OrzpuAoII9sU3fl8Ug4rTMtwy oN5uhuuQkPkbN58/SISC460uTKpCQlUcbAXS/qv4aslDra2+2wAVUljSRaOWooGetT D7Rbca5gReLYPHHEcW/pPymbNz99rEY7FQRQHxwU= X-SMAIL-HELO: localhost.localdomain Received: from unknown (HELO localhost.localdomain)([114.249.58.160]) by sina.com (10.54.253.32) with ESMTP id 69734CD700001752; Fri, 23 Jan 2026 18:26:35 +0800 (CST) X-Sender: hdanton@sina.com X-Auth-ID: hdanton@sina.com Authentication-Results: sina.com; spf=none smtp.mailfrom=hdanton@sina.com; dkim=none header.i=none; dmarc=none action=none header.from=hdanton@sina.com X-SMAIL-MID: 2305584456648 X-SMAIL-UIID: 60AD2A9D571B4C46AB20057DC6C98948-20260123-182635-1 From: Hillf Danton To: syzbot Cc: linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com Subject: Re: [syzbot] [bluetooth?] KASAN: slab-use-after-free Read in l2cap_sock_ready_cb (2) Date: Fri, 23 Jan 2026 18:26:22 +0800 Message-ID: <20260123102623.2318-1-hdanton@sina.com> In-Reply-To: <69729a7e.a00a0220.2cf64e.0003.GAE@google.com> References: Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit > Date: Thu, 22 Jan 2026 13:45:34 -0800 > syzbot has found a reproducer for the following issue on: > > HEAD commit: a66191c590b3 Merge tag 'hyperv-fixes-signed-20260121' of g.. > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=11b467fc580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=f1fac0919970b671 > dashboard link: https://syzkaller.appspot.com/bug?extid=9265e754091c2d27ea29 > compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=143e7f9a580000 #syz test --- x/net/bluetooth/af_bluetooth.c +++ y/net/bluetooth/af_bluetooth.c @@ -226,6 +226,7 @@ void bt_accept_enqueue(struct sock *pare list_add_tail(&bt_sk(sk)->accept_q, &bt_sk(parent)->accept_q); bt_sk(sk)->parent = parent; + sock_hold(parent); /* Copy credentials from parent since for incoming connections the * socket is allocated by the kernel. @@ -258,6 +259,7 @@ void bt_accept_unlink(struct sock *sk) list_del_init(&bt_sk(sk)->accept_q); sk_acceptq_removed(bt_sk(sk)->parent); + sock_put(bt_sk(sk)->parent); bt_sk(sk)->parent = NULL; sock_put(sk); } --- x/net/bluetooth/l2cap_sock.c +++ y/net/bluetooth/l2cap_sock.c @@ -1473,6 +1473,8 @@ static struct l2cap_chan *l2cap_sock_new { struct sock *sk, *parent = chan->data; + if (!parent) + return NULL; lock_sock(parent); /* Check for backlog size */ --