From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mta1.migadu.com (out-224.mta1.migadu.com [95.215.58.224]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 340DD333439 for ; Wed, 26 Aug 2026 05:38:21 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=95.215.58.224 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787722704; cv=none; b=s5YmMKFiucOxPPPpCY5ViQdjbGiOleEth9bf0/o7zEj4gL4uZI+yQJJj2J62v0Woeeo+59peiMYWJYgJTyhOTY/12eS9+f0670y124RUE5Oxahl25gmdQjLgIQf+GaN723tE3LNKw5qFtyXCpBfC5+YsD36+Mb1FPcNhCliYzbE= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1787722704; c=relaxed/simple; bh=qwiPevUVxC4HbDb6mnNEuMiwDcUKPc5Co7Hl7T7UNxg=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=VjfDcN285e4RChMMUO7C9wqSTKfahdRZW7jZBEtR5e0MAhHb3dzjKO4kjUe+nJf/a1MFQkwA+nHO1gb9+2zRBT3Kj0RcFkKQTXDDX73SMMUhr/vRvbg0Xfft8ANI7ycRnX4VALYikyl9qZnBfQLdh/vchDhAnI7qo9D4M+8PhXk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linux.dev; spf=pass smtp.mailfrom=linux.dev; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b=FzeHXx7t; arc=none smtp.client-ip=95.215.58.224 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 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.dev header.i=@linux.dev header.b="FzeHXx7t" X-Envelope-To: netdev@vger.kernel.org DKIM-Signature: a=rsa-sha256; bh=qwiPevUVxC4HbDb6mnNEuMiwDcUKPc5Co7Hl7T7UNxg=; c=simple/simple; d=linux.dev; h=from:to:subject:date:message-id:mime-version:content-type; s=key1; t=1787722700; v=1; x=1788327500; b=FzeHXx7tdPQ1G1BOqAHeUL1P06/vt1CsEM3E85XHyKz2U7jBVpqSv6tnZEquBwVK9uE8E7Yc wv8tLJZ9gJbUOvo3LLGiW0qIW2wdob2geY3blmb/y/nOO+/PSfNLAclWn7b0JajArZF/6TWCNGg ausfuwFSop5UDwvjxMmiDnPQ= X-Envelope-To: netdev@vger.kernel.org Received: from [IPV6:2408:820c:2709:4101:c80e:c4e9:a56c:6f95] (2a14:7586:6109:1::198) by smtp.migadu.com with ESMTPS id 3a4306510f3658bc; Wed, 26 Aug 2026 05:38:10 +0000 X-Mizu-Trace-ID: 3a4306510f3658bc X-Migadu-Flow: FLOW_OUT Message-ID: <8ea9c9ce-e1ed-475b-90d3-abf1bd86c3d7@linux.dev> Date: Wed, 26 Aug 2026 13:38:02 +0800 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [BUG] KASAN: slab-use-after-free Read in slip_receive_buf To: Eric Dumazet , Jaeyoung Chung Cc: andrew+netdev@lunn.ch, davem@davemloft.net, kuba@kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, 726ksm@gmail.com, kees@kernel.org, linux-kernel@vger.kernel.org, eulgyukim@snu.ac.kr References: <20260825150655.1450271-1-jjy600901@snu.ac.kr> From: Qingfang Deng In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi, On 2026/8/25 23:27, Eric Dumazet wrote: > On Tue, Aug 25, 2026 at 5:07 PM Jaeyoung Chung wrote: >> Hello, >> >> We found a "KASAN: slab-use-after-free Read in slip_receive_buf" on Linux v7.2. >> The issue was found by our own race fuzzer. We have not analyzed the root cause, >> so we do not have a proposed fix to offer. >> >> To reproduce the race reliably, we applied the delay patch below to the >> kernel and ran the C reproducer as root inside an x86_64 QEMU guest. The >> crash log we observed, the delay patch and the reproducer are all included >> below. >> >> The following kernel config options are required to reproduce the issue: >> CONFIG_SLIP=y >> CONFIG_LEGACY_TIOCSTI=y >> CONFIG_UNIX98_PTYS=y >> CONFIG_TTY=y >> CONFIG_KASAN=y >> >> We hope this report is useful. Please let us know if any further >> information would help. >> >> Reported-by: Eulgyu Kim >> Reported-by: Jaeyoung Chung > This rings a bell; I had a local syzbot report for this issue a while back. > > I think we should remove slip_hangup(). ppp_async.c and ppp_synctty.c have the same anti-pattern. Should we remove theirs as well?