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 59E91226864; Thu, 19 Dec 2024 15:53:18 +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=1734623598; cv=none; b=gBv/Pp2+JSfzZFM5HEdcUdYcBBxJ1Tl5i81XzEiLpTVOd9BSedEhfUT9C6WcYpvYOxS04DueT5wecQJaNBGU14OhVNJmP178W5nQmuvcBPKtmh45pyhQf4/X4X0zHmSGb2epaND8Tapasd7T+Pqcxoyx9BbsQHlbjqF76GwHf74= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1734623598; c=relaxed/simple; bh=+PkMCmdIXUAJZ/qkduIdOg0YB+gtUcyD0jLuCZu1NbU=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=PSW5KaS/lvotbso598ABlAqjEFmpvBgMXwnhSxgHYYSYwUedtcIh5UAUyV8X6Ye14PC89GD3HLia1Cij4cm5aYgfGMucJvmsO0fbsAPWFKm5pgzCYiEeLufqV1QZALTAqFlvKAZ6uM4rr+JDXKbkHDVcWfILeLmA6/jdbyZcyTA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=buGKlnWi; 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="buGKlnWi" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C5C02C4CECE; Thu, 19 Dec 2024 15:53:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1734623598; bh=+PkMCmdIXUAJZ/qkduIdOg0YB+gtUcyD0jLuCZu1NbU=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=buGKlnWi+OFuEuC+spW8RN5mmeyMQ7mj08UkFxXE/EfSo+bcSqiSLj/tr8JE4A9pn 3x/FDTd6K8O11w3DM94JuZ9F4NJvBZPB5vU+D4+3MigfaNcL3nOlh7yOWDlOynm+Bs CQ9bMmj7rjX+PL2qfpVdfCI5a393JZap86HApygY1g0rYCsnl5dttoex4rm5VZabsb 20JDL0OPjvRDhrKHDNcJvwuJIouJdOIzRp4Ts4/MeYpWzF8VaLosiSWhURXLS0zY6K SJNNBUnfeBLHxBlHkgYqbwEbV2RR8bZvcFZzgi2Y4W0H5yL1xXU2lYuSeCyLqGIYhs aruIJFM3UWQUw== Message-ID: Date: Thu, 19 Dec 2024 16:53:04 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Beta Subject: Re: [syzbot] [net?] general protection fault in put_page (4) Content-Language: en-GB To: Aleksandr Nogikh Cc: Eric Dumazet , davem@davemloft.net, dsahern@kernel.org, horms@kernel.org, kuba@kernel.org, linux-kernel@vger.kernel.org, martineau@kernel.org, netdev@vger.kernel.org, pabeni@redhat.com, syzbot , syzkaller-bugs@googlegroups.com References: <6761aed9.050a0220.29fcd0.006b.GAE@google.com> From: Matthieu Baerts Autocrypt: addr=matttbe@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 8bit Hi Aleksandr, Thank you for your reply! On 19/12/2024 10:59, Aleksandr Nogikh wrote: > Hi Matthieu, > > On Wed, Dec 18, 2024 at 7:06 PM 'Matthieu Baerts' via syzkaller-bugs > wrote: >> >> Hi Eric, >> >> On 17/12/2024 18:06, Eric Dumazet wrote: >>> On Tue, Dec 17, 2024 at 6:03 PM syzbot >>> wrote: >>>> >>>> Hello, >>>> >>>> syzbot found the following issue on: >>>> >>>> HEAD commit: 78d4f34e2115 Linux 6.13-rc3 >>>> git tree: upstream >>>> console+strace: https://syzkaller.appspot.com/x/log.txt?x=16445730580000 >>>> kernel config: https://syzkaller.appspot.com/x/.config?x=6c532525a32eb57d >>>> dashboard link: https://syzkaller.appspot.com/bug?extid=38a095a81f30d82884c1 >>>> compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40 >>>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=169b0b44580000 >>>> C reproducer: https://syzkaller.appspot.com/x/repro.c?x=13f502df980000 >>>> >>>> Downloadable assets: >>>> disk image: https://storage.googleapis.com/syzbot-assets/7129ee07f8aa/disk-78d4f34e.raw.xz >>>> vmlinux: https://storage.googleapis.com/syzbot-assets/c23c0af59a16/vmlinux-78d4f34e.xz >>>> kernel image: https://storage.googleapis.com/syzbot-assets/031aecf04ea7/bzImage-78d4f34e.xz >>>> >>>> The issue was bisected to: >>>> >>>> commit b83fbca1b4c9c45628aa55d582c14825b0e71c2b >>>> Author: Matthieu Baerts (NGI0) >>>> Date: Mon Sep 2 10:45:53 2024 +0000 >>>> >>>> mptcp: pm: reduce entries iterations on connect >>>> >>>> bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=163682df980000 >>>> final oops: https://syzkaller.appspot.com/x/report.txt?x=153682df980000 >>>> console output: https://syzkaller.appspot.com/x/log.txt?x=113682df980000 >> >> (...) >> >>> I spent some time on this bug before releasing it, because I have >>> other syzbot reports probably >>> caused by the same issue, hinting at shinfo->nr_frags corruption. >>> >>> I will hold these reports to avoid flooding the mailing list. >> >> Thank you for having released this bug report! >> >> The bisected commit looks unrelated. I don't know if we can tell syzbot >> to "skip this commit and try harder". > > As of now, it's not yet supported. I've added a +1 mention to the > corresponding syzbot backlog issue: > https://github.com/google/syzkaller/issues/3491 Thank you for that! > I've also looked at the bisection log of this particular report and > the only suspicious part is that syzbot could have been too eager to > minimize the .config file. A different set of enabled options changed > the cash title from "general protection fault in put_page" to "BUG: > unable to handle kernel NULL pointer dereference in skb_release_data", > but the rest of the bisection log looks reasonable to me. OK, thank you for having looked! The other title sounds better to describe this issue. >> I'm trying to run a 'git bisect' on my side since this morning: the >> issue seems to be older, between v6.10 and v6.11 if I'm not mistaken. >> When using the same kernel config, I'm getting quite a few issues on >> older commits (compilation, other warnings, etc.), plus the compilation >> is slow on my laptop. I will update you if I can find anything useful. > > If you find the proper guilty commit, it would also really help debug > the bot's bisection result. Will do if I can find something! > In case it may help you during the manual bisection, syzbot > cherry-picks this set of fix commits while doing the bisection: > https://github.com/google/syzkaller/blob/master/pkg/vcs/linux_patches.go#L60 I appreciate the hint. It looks like all these commits are old enough to be included in the range I'm testing for the moment. I adapted my scripts to detect "other issues" and skip the commit. Hopefully I can achieve something. Cheers, Matt -- Sponsored by the NGI0 Core fund.