Re: [syzbot] [f2fs?] WARNING: lock held when returning to user space in f2fs_ioc_start_atomic_write

[Chao Yu <chao@kernel.org>]

#syz fix: f2fs: atomic: fix to forbid dio in atomic_file

On 2024/8/14 19:51, syzbot wrote:
> Hello,
> 
> syzbot found the following issue on:
> 
> HEAD commit:    9e6869691724 Add linux-next specific files for 20240812
> git tree:       linux-next
> console+strace: https://syzkaller.appspot.com/x/log.txt?x=1431e405980000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=61ba6f3b22ee5467
> dashboard link: https://syzkaller.appspot.com/bug?extid=733300ca0a9baca7e245
> 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=120ed77d980000
> C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=130e0ef3980000
> 
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/f1b086192f50/disk-9e686969.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/b457920fb52e/vmlinux-9e686969.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/e63ba9cce98a/bzImage-9e686969.xz
> mounted in repro: https://storage.googleapis.com/syzbot-assets/08b48c782593/mount_0.gz
> 
> The issue was bisected to:
> 
> commit 374a8881ce4ccf787f5381a39f825cb17a3f6b14
> Author: Chao Yu <chao@kernel.org>
> Date:   Tue Jun 25 03:13:51 2024 +0000
> 
>      f2fs: atomic: fix to forbid dio in atomic_file
> 
> bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=10741429980000
> final oops:     https://syzkaller.appspot.com/x/report.txt?x=12741429980000
> console output: https://syzkaller.appspot.com/x/log.txt?x=14741429980000
> 
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+733300ca0a9baca7e245@syzkaller.appspotmail.com
> Fixes: 374a8881ce4c ("f2fs: atomic: fix to forbid dio in atomic_file")
> 
> F2FS-fs (loop0): Found nat_bits in checkpoint
> F2FS-fs (loop0): Mounted with checkpoint version = 48b305e5
> syz-executor312: attempt to access beyond end of device
> loop0: rw=10241, sector=45096, nr_sectors = 8 limit=40427
> ================================================
> WARNING: lock held when returning to user space!
> 6.11.0-rc3-next-20240812-syzkaller #0 Not tainted
> ------------------------------------------------
> syz-executor312/5227 is leaving the kernel with locks still held!
> 1 lock held by syz-executor312/5227:
>   #0: ffff8880695aa0e0 (&fi->i_gc_rwsem[READ]){+.+.}-{3:3}, at: f2fs_down_write fs/f2fs/f2fs.h:2196 [inline]
>   #0: ffff8880695aa0e0 (&fi->i_gc_rwsem[READ]){+.+.}-{3:3}, at: f2fs_ioc_start_atomic_write+0x2ed/0xac0 fs/f2fs/file.c:2163
> 
> 
> ---
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