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Sat, 6 Sep 2025 02:21:24 -0400 (EDT) X-Mailer: MessagingEngine.com Webmail Interface Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ThreadId: AxX0oEVx0u-k Date: Sat, 06 Sep 2025 08:21:04 +0200 From: "Arnd Bergmann" To: syzbot , "Anders Roxell" , "Christian Brauner" , "Yangtao Li" , "John Paul Adrian Glaubitz" , "Greg Kroah-Hartman" , kstewart@linuxfoundation.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, "'pombredanne@nexb.com'" , "Viacheslav Dubeyko" , syzkaller-bugs@googlegroups.com, "Thomas Gleixner" , yepeilin.cs@gmail.com Message-Id: <66114372-5bd8-4f1b-8aea-1f6c4ec91bda@app.fastmail.com> In-Reply-To: <68bbccf3.a70a0220.7a912.02c1.GAE@google.com> References: <68bbccf3.a70a0220.7a912.02c1.GAE@google.com> Subject: Re: [syzbot] [hfs?] general protection fault in hfs_find_init Content-Type: text/plain Content-Transfer-Encoding: 7bit On Sat, Sep 6, 2025, at 07:56, syzbot wrote: > syzbot suspects this issue was fixed by commit: > > commit 42b0ef01e6b5e9c77b383d32c25a0ec2a735d08a > Author: Arnd Bergmann > Date: Fri Jul 11 08:46:51 2025 +0000 > > block: fix FS_IOC_GETLBMD_CAP parsing in blkdev_common_ioctl() > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=17c0d312580000 > start commit: ee88bddf7f2f Merge tag 'bpf-fixes' of git://git.kernel.org.. > git tree: upstream > kernel config: https://syzkaller.appspot.com/x/.config?x=28cc6f051378bb16 > dashboard link: https://syzkaller.appspot.com/bug?extid=7ca256d0da4af073b2e2 > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1026b182580000 > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=159e0f0c580000 I took a look and concluded that my patch is unlikely to have fixed the issue, because: - my patch was wrong and needed another fixup on top - the reproducer and kernel log show no reference to ioctl() calls, so they do not directly interact with the code I changed. It is possible that my patch is hiding the root cause for the problem, if part of the reproducer relies on a prior call to ioctl() on a block device and this ioctl was broken by my patch. This still sounds like a long shot though, and my first guess would be that the bisection went wrong, possibly by running into more than one issue, or an unreliable reproducer. Arnd