From: Matthew Wilcox <willy@infradead.org>
To: syzbot <syzbot+c0dc46208750f063d0e0@syzkaller.appspotmail.com>
Cc: Dominique Martinet <asmadeus@codewreck.org>,
v9fs@lists.linux.dev, dhowells@redhat.com, jlayton@kernel.org,
linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
netfs@lists.linux.dev, syzkaller-bugs@googlegroups.com
Subject: Re: [syzbot] [netfs?] kernel BUG in folio_unlock (3)
Date: Thu, 20 Feb 2025 16:15:53 +0000 [thread overview]
Message-ID: <Z7dVOaTWTVCojNzr@casper.infradead.org> (raw)
In-Reply-To: <67b75198.050a0220.14d86d.02e2.GAE@google.com>
On Thu, Feb 20, 2025 at 08:00:24AM -0800, syzbot wrote:
> ------------[ cut here ]------------
> kernel BUG at mm/filemap.c:1499!
Tried to unlock a folio that wasn't locked.
The entire log is interesting:
https://syzkaller.appspot.com/x/log.txt?x=12af2fdf980000
It injects a failure which hits p9_tag_alloc() (so adding the 9p people
to the cc)
The page dump is:
page: refcount:1 mapcount:0 mapping:ffff888035b30890 index:0x0 pfn:0x37e9a
memcg:ffff88801c6be000
aops:v9fs_addr_operations ino:2721d72 dentry name(?):"file0"
flags: 0xfff20000000020(lru|node=0|zone=1|lastcpupid=0x7ff)
raw: 00fff20000000020 ffffea0000e1d1c8 ffff88801b0b31a0 ffff888035b30890
raw: 0000000000000000 0000000000000000 00000001ffffffff ffff88801c6be000
page dumped because: VM_BUG_ON_FOLIO(!folio_test_locked(folio))
> Call Trace:
> <TASK>
> netfs_perform_write+0xc04/0x2140 fs/netfs/buffered_write.c:400
> netfs_buffered_write_iter_locked fs/netfs/buffered_write.c:445 [inline]
> netfs_file_write_iter+0x494/0x550 fs/netfs/buffered_write.c:484
> v9fs_file_write_iter+0x9b/0x100 fs/9p/vfs_file.c:407
> new_sync_write fs/read_write.c:586 [inline]
> vfs_write+0x5ae/0x1150 fs/read_write.c:679
> ksys_write+0x12b/0x250 fs/read_write.c:731
next prev parent reply other threads:[~2025-02-20 16:15 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-02-20 16:00 [syzbot] [netfs?] kernel BUG in folio_unlock (3) syzbot
2025-02-20 16:15 ` Matthew Wilcox [this message]
2025-02-20 22:05 ` Dominique Martinet
2025-02-26 8:41 ` David Howells
2025-05-31 23:20 ` syzbot
2025-06-01 0:26 ` Matthew Wilcox
2025-06-11 14:08 ` Aleksandr Nogikh
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