From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (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 6C387CA6F; Thu, 19 Feb 2026 01:38:36 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771465116; cv=none; b=Tvg8crh916log+rYnNf8MqokSxj1Ivg3F0sz+T00sXzhXIkVCyKtvvLsEpdt1XkPdiAluSj4iQdrAWSzuW2PtHp0c8M75kUqNOkvv8nogFtey+e9DV9wcjeMTxk62efXlErBlgaaaYJMy/goZZSARU9LYrb/Q/mUDrkU7nJ3MRw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771465116; c=relaxed/simple; bh=0eLuBTDqPctu+4vbIg6FzRU6nHHXVxKUVCW3TGEggfw=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=TUa2+GWLbjlJsdOho5sjrOYmnJY94Iv0+qncwWr30ERgIlvhXFaYJ8YQ++fOCkNSs673kESelV7FdBreLle8ekhOfX67uDorfKId+EIvDRT8R6N2nLa3twdydtL063fG7QHjsTIEzINZZF1B3JmnKsHNgO0pvrJdwppmdSeqVUw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=SyHZtKA0; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="SyHZtKA0" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6EF79C116D0; Thu, 19 Feb 2026 01:38:35 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771465116; bh=0eLuBTDqPctu+4vbIg6FzRU6nHHXVxKUVCW3TGEggfw=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=SyHZtKA0F7QKxZNRtBTylkK0I5JP65gi+CAs/td7PHI7nayopt+05rDJODPufFr/d R5Don5ik1pXb14VN6juCitrSzmBpZktM1uo0L2HWKQJrNTT3VO36PaKLR6qDJDUmap TP7g+VErpaeYQCBLkxzufScsOcQuYPjMEbr3AGr93NZax3dgaiyWjgZSGK/XrhCKbL ou08B/R9jnAoERMaIB7QXrGyr6nDJw5qPDhfcXmOjELpsAiPLIuGLyrJxt1EooTW3H kKHLDrsbJGtWCGfX8Kcez6zAIYcLJSLPWmhyKsZ1Y/k7zn0Anky5i9QRjYWWTVQWsP r8xdfp+z6zQcw== Message-ID: <1e4e903b-143f-4f95-a41d-2a87cdcaf2c4@kernel.org> Date: Thu, 19 Feb 2026 10:33:22 +0900 Precedence: bulk X-Mailing-List: linux-ide@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [syzbot] [ide?] UBSAN: shift-out-of-bounds in ata_qc_issue To: Niklas Cassel , syzbot Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com References: <6994d5c7.a70a0220.2c38d7.010b.GAE@google.com> Content-Language: en-US From: Damien Le Moal Organization: Western Digital Research In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 2/18/26 6:45 PM, Niklas Cassel wrote: > On Tue, Feb 17, 2026 at 12:55:35PM -0800, syzbot wrote: >> Hello, >> >> syzbot found the following issue on: >> >> HEAD commit: ca4ee40bf13d Partly revert "drm/hyperv: Remove reference t.. >> git tree: upstream >> console output: https://syzkaller.appspot.com/x/log.txt?x=13c6c722580000 >> kernel config: https://syzkaller.appspot.com/x/.config?x=a771bfd268751cd6 >> dashboard link: https://syzkaller.appspot.com/bug?extid=1f77b8ca15336fff21ff >> compiler: gcc (Debian 14.2.0-19) 14.2.0, GNU ld (GNU Binutils for Debian) 2.44 >> >> Unfortunately, I don't have any reproducer for this issue yet. >> >> Downloadable assets: >> disk image (non-bootable): https://storage.googleapis.com/syzbot-assets/d900f083ada3/non_bootable_disk-ca4ee40b.raw.xz >> vmlinux: https://storage.googleapis.com/syzbot-assets/c714adf37ddd/vmlinux-ca4ee40b.xz >> kernel image: https://storage.googleapis.com/syzbot-assets/4d56cd9f6175/bzImage-ca4ee40b.xz >> >> IMPORTANT: if you fix the issue, please add the following tag to the commit: >> Reported-by: syzbot+1f77b8ca15336fff21ff@syzkaller.appspotmail.com >> >> ------------[ cut here ]------------ >> UBSAN: shift-out-of-bounds in drivers/ata/libata-core.c:5166:24 >> shift exponent 4210818301 is too large for 64-bit type 'long long unsigned int' > > 4210818301 is 0xfafbfcfd > > 0xfafbfcfd is ATA_TAG_POISON. > > ATA_TAG_POISON is set by ata_qc_free(), so it appears that > ata_scsi_deferred_qc_work() is trying to issue a QC that has > already been freed. I checked the code but I fail to see any path that can lead to this happening. I did more tests using qemu q35 machine as used by syzbot, and everything looks fine. So not sure what is happening here. I will dig further. -- Damien Le Moal Western Digital Research