From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=95.215.58.53 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793526688; b=AfG+PRZI1TRyHOkVT/w2sbzxtthivFurRjngqGtXc+nzqg97VMeD5p5vTMWn6vODve37 VgYiBxVjwqdEoegTC0c2UzAYEMxJkfmyLXPjbOn6iM12WwjU0N0YGasQfHsgqI5LRUKU0 T9Rj0x4/95zHapExCEv0NcKUTlWqglibe855gcpYYVFWpUM3WC8U61RkqkQavd/wVzT/b 4cYCVkAI0v3pTpZWXuYg14zDWHKaPnUBtxcDqavfq2hmeaRWOu7IztxlCX80jWzXMorTq 0r4jADXQsnFgYpmbtskUN9migUJ1kYKuwK01nBryWmXkywYw7vVR3GGSSlRd3YGE1fw== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793526688; h=DMARC-Filter:X-Envelope-To:DKIM-Signature:X-Envelope-To:Received: X-Mizu-Trace-ID:X-Migadu-Flow:Message-ID:Date:MIME-Version:User-Agent: Subject:To:References:From:In-Reply-To:Content-Type: Content-Transfer-Encoding; bh=42mltXfOHa8qQEgF7vx2IvMlukJoJC4Ac1VKSCu6M58=; b=VqF5BxO4E+qRMrqkBda+O/LjB0z/+8Uw7JJzZ5lQByyjcYdFPmGSMJLunhgsqVjkt9g4 XMychcenWXkfTOJvRWQoZ1UcHPgm+aoy2bphEKAta5qvmvNjxTbr1wqVRmeze2RLS8Bg2 6gvmv+hNpn6qHXn/SOyrV+CqX3g5gdDmbCE+atCMWJIC77dIIEtahWYuCb3BoIGLNt2I8 aq3mVX60VyUpC1UTOlLy3WjK17NlrY97933+L41LmGqBY/WfXN9LsF2RDzX8f7GxPzuwe dZQ0FHWRzZY3ozRyXwUSFzFj9mU/IEs0aCGUDrT0LbQIDtQ1z13UbTxKCHzjbOyIDDA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; arc=none smtp.remote-ip=95.215.58.53 Received: from mta1.migadu.com (out-53.mta1.migadu.com [95.215.58.53]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5AFC8606A325 for ; Sun, 1 Nov 2026 09:51:22 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 5AFC8606A325 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linux.dev X-Envelope-To: linux-kernel@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=+LcOo+yzU61N5f/ovbIqmgFP1ag60jqXkCX/q1zSclw=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1793526680; v=1; x=1794131480; b=Q34tkcKlbgVeEA19/oLfRhDgHn0n51q7h03Zi8nXZlWgq7chnBC8JxMgHoF3yzURkNd8r7Kq ZMOiKmnnKFcY00XKrM8yYOFkwYcoJ2KQtjfGIbBcb9qCWv579aNLAirrAVEuJpTzt+HOqAlzKab 3Gu78SHHJJKCK5M/wwMhy+GY= X-Envelope-To: linux-kernel@vger.kernel.org Received: by smtp.migadu.com with ESMTPS id a8b3a4003f078db1; Sun, 01 Nov 2026 09:51:20 +0000 X-Mizu-Trace-ID: a8b3a4003f078db1 X-Migadu-Flow: FLOW_OUT Message-ID: <7ce7a3c9-0e2f-4f01-a29c-f589f03f581c@linux.dev> Date: Sun, 1 Nov 2026 17:51:13 +0800 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [syzbot] [net?] BUG: unable to handle kernel paging request in nsim_drv_port_add (2) To: syzbot , linux-kernel@vger.kernel.org, netdev@vger.kernel.org, syzkaller-bugs@googlegroups.com, stitch@zju.edu.cn References: <6ae6e3d1.7fe51036.1ecf7.0016.GAE@google.com> From: Jiayuan Chen In-Reply-To: <6ae6e3d1.7fe51036.1ecf7.0016.GAE@google.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 11/1/26 3:01 PM, syzbot wrote: > Hello, > > syzbot found the following issue on: > > HEAD commit: 36aad21d50d1 Merge tag 'ksmbd-for-7.4-rc1-part2' of git://.. > git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git > console output: https://syzkaller.appspot.com/x/log.txt?x=1332b159580000 > kernel config: https://syzkaller.appspot.com/x/.config?x=dc4462df6d1062fe > dashboard link: https://syzkaller.appspot.com/bug?extid=b3fca27eb4005f0111f4 > compiler: Debian clang version 22.1.8 (1~deb13u4), Debian LLD 22.1.8 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=1194b795580000 > > AI-generated root cause summary: > In netdevsim, sysfs device attributes such as 'new_port' and 'del_port' are > exposed at the device level on nsim_bus_dev without holding device_lock or > checking if the driver is bound. An access via sysfs after the driver has been > unbound, after a failed probe, or concurrently with device removal finds drvdata > set to NULL; passing this NULL pointer to priv_to_devlink() computes a negative > offset from NULL, triggering a kernel page fault crash when attempting to > acquire devlink->lock. > > full analysis: https://syzkaller.appspot.com/x/ai_root_cause?x=b3fca27eb4005f0111f4 This looks like the same issue Jiacheng's pending patch addresses, new_port/del_port don't take device_lock nor check drvdata, so a write after unbind hits a NULL nsim_dev: https://lore.kernel.org/netdev/20261012135941.78329-1-stitch@zju.edu.cn/