Re: [syzbot] [btrfs?] WARNING in create_pending_snapshot

From: syzbot
Date: Sat Nov 11 2023 - 22:55:02 EST


Hello,

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

BTRFS info (device loop0): checking UUID tree
------------[ cut here ]------------
BTRFS: Transaction aborted (error -17)
WARNING: CPU: 0 PID: 5480 at fs/btrfs/transaction.c:1778 create_pending_snapshot+0x25f4/0x2b70 fs/btrfs/transaction.c:1778
Modules linked in:
CPU: 0 PID: 5480 Comm: syz-executor.0 Not tainted 6.6.0-syzkaller-15365-g305230142ae0-dirty #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/09/2023
RIP: 0010:create_pending_snapshot+0x25f4/0x2b70 fs/btrfs/transaction.c:1778
Code: f8 fd 48 c7 c7 00 43 ab 8b 89 de e8 76 4b be fd 0f 0b e9 30 f3 ff ff e8 7a 8d f8 fd 48 c7 c7 00 43 ab 8b 89 de e8 5c 4b be fd <0f> 0b e9 f8 f6 ff ff e8 60 8d f8 fd 48 c7 c7 00 43 ab 8b 89 de e8
RSP: 0018:ffffc900094cf580 EFLAGS: 00010246
RAX: ca9849a0d3eb4500 RBX: 00000000ffffffef RCX: ffff88807ac39dc0
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000000
RBP: ffffc900094cf870 R08: ffffffff81547c82 R09: 1ffff92001299e04
R10: dffffc0000000000 R11: fffff52001299e05 R12: ffff88807ca30500
R13: 00000000ffffffef R14: 0000000000000000 R15: ffff88807ca304a0
FS: 00007f9af6b8a6c0(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f15547ad018 CR3: 0000000028d0c000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
<TASK>
create_pending_snapshots+0x195/0x1d0 fs/btrfs/transaction.c:1967
btrfs_commit_transaction+0xf1c/0x3730 fs/btrfs/transaction.c:2440
create_snapshot+0x4a5/0x7e0 fs/btrfs/ioctl.c:845
btrfs_mksubvol+0x5d0/0x750 fs/btrfs/ioctl.c:995
btrfs_mksnapshot+0xb5/0xf0 fs/btrfs/ioctl.c:1041
__btrfs_ioctl_snap_create+0x344/0x460 fs/btrfs/ioctl.c:1294
btrfs_ioctl_snap_create+0x13c/0x190 fs/btrfs/ioctl.c:1321
btrfs_ioctl+0xbbf/0xd40
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:871 [inline]
__se_sys_ioctl+0xf8/0x170 fs/ioctl.c:857
do_syscall_x64 arch/x86/entry/common.c:51 [inline]
do_syscall_64+0x44/0x110 arch/x86/entry/common.c:82
entry_SYSCALL_64_after_hwframe+0x63/0x6b
RIP: 0033:0x7f9af5e7cae9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 20 00 00 90 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 b0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f9af6b8a0c8 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f9af5f9bf80 RCX: 00007f9af5e7cae9
RDX: 0000000020000a80 RSI: 0000000050009401 RDI: 0000000000000004
RBP: 00007f9af5ec847a R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 000000000000000b R14: 00007f9af5f9bf80 R15: 00007ffcf277e6d8
</TASK>


Tested on:

commit: 30523014 Merge tag 'pm-6.7-rc1-2' of git://git.kernel...
git tree: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
console output: https://syzkaller.appspot.com/x/log.txt?x=112cafc4e80000
kernel config: https://syzkaller.appspot.com/x/.config?x=beb32a598fd79db9
dashboard link: https://syzkaller.appspot.com/bug?extid=4d81015bc10889fd12ea
compiler: Debian clang version 15.0.6, GNU ld (GNU Binutils for Debian) 2.40
patch: https://syzkaller.appspot.com/x/patch.diff?x=15c3dc70e80000