Re: [syzbot] [iomap?] [xfs?] WARNING in iomap_write_begin

syzbot
2024-08-30T10:19:02Z

Hello,

syzbot has tested the proposed patch but the reproducer is still triggering an issue:
WARNING in iomap_write_begin

XFS (loop0): Mounting V5 Filesystem bfdc47fc-10d8-4eed-a562-11a831b3f791
XFS (loop0): Ending clean mount
XFS (loop0): Quotacheck needed: Please wait.
XFS (loop0): Quotacheck: Done.
------------[ cut here ]------------
WARNING: CPU: 0 PID: 6077 at fs/iomap/buffered-io.c:727 __iomap_write_begin fs/iomap/buffered-io.c:727 [inline]
WARNING: CPU: 0 PID: 6077 at fs/iomap/buffered-io.c:727 iomap_write_begin+0x13f0/0x16f0 fs/iomap/buffered-io.c:830
Modules linked in:
CPU: 0 UID: 0 PID: 6077 Comm: syz.0.15 Not tainted 6.11.0-rc2-syzkaller-00111-gee9a43b7cfe2-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024
RIP: 0010:__iomap_write_begin fs/iomap/buffered-io.c:727 [inline]
RIP: 0010:iomap_write_begin+0x13f0/0x16f0 fs/iomap/buffered-io.c:830
Code: b5 0d 01 90 48 c7 c7 a0 54 fa 8b e8 da 19 2b ff 90 0f 0b 90 90 e9 74 ef ff ff e8 5b f1 68 ff e9 4b f6 ff ff e8 51 f1 68 ff 90 <0f> 0b 90 bb fb ff ff ff e9 e9 fe ff ff e8 3e f1 68 ff 90 0f 0b 90
RSP: 0018:ffffc90003e977c0 EFLAGS: 00010293
RAX: ffffffff822a858f RBX: 0000000000000080 RCX: ffff888020aeda00
RDX: 0000000000000000 RSI: 0000000000000080 RDI: 0000000000000000
RBP: ffffc90003e97a50 R08: ffffffff822a8294 R09: 1ffff11004494cf9
R10: dffffc0000000000 R11: ffffed1004494cfa R12: ffffc90003e979b0
R13: ffffc90003e97bf0 R14: ffffc90003e97990 R15: 0000000000000800
FS: 00007f4d396276c0(0000) GS:ffff8880b9200000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000020001000 CR3: 0000000023f3a000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
iomap_unshare_iter fs/iomap/buffered-io.c:1351 [inline]
iomap_file_unshare+0x460/0x780 fs/iomap/buffered-io.c:1391
xfs_reflink_unshare+0x173/0x5f0 fs/xfs/xfs_reflink.c:1681
xfs_file_fallocate+0x6be/0xa50 fs/xfs/xfs_file.c:997
vfs_fallocate+0x553/0x6c0 fs/open.c:334
ksys_fallocate fs/open.c:357 [inline]
__do_sys_fallocate fs/open.c:365 [inline]
__se_sys_fallocate fs/open.c:363 [inline]
__x64_sys_fallocate+0xbd/0x110 fs/open.c:363
do_syscall_x64 arch/x86/entry/common.c:52 [inline]
do_syscall_64+0xf3/0x230 arch/x86/entry/common.c:83
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f4d387779f9
Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f4d39627038 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f4d38905f80 RCX: 00007f4d387779f9
RDX: 0000000000000000 RSI: 0000000000000040 RDI: 0000000000000006
RBP: 00007f4d387e58ee R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000002000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f4d38905f80 R15: 00007ffd9e61c108
</TASK>

Tested on:

commit: ee9a43b7 Merge tag 'net-6.11-rc3' of git://git.kernel...
git tree: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=173e3eeb980000
kernel config: https://syzkaller.appspot.com/x/.config?x=9358cc4a2e37fd30
dashboard link: https://syzkaller.appspot.com/bug?extid=296b1c84b9cbf306e5a0
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=16b67cdb980000