Re: [syzbot] [btrfs?] kernel BUG in prepare_to_merge

[Qu Wenruo]

On 2023/7/2 04:46, syzbot wrote:
> Hello,
>
> syzbot found the following issue on:
>
> HEAD commit:    533925cb7604 Merge tag 'riscv-for-linus-6.5-mw1' of git://..
> git tree:       upstream
> console output: https://syzkaller.appspot.com/x/log.txt?x=14d8b610a80000
> kernel config:  https://syzkaller.appspot.com/x/.config?x=12464973c17d2b37
> dashboard link: https://syzkaller.appspot.com/bug?extid=ae97a827ae1c3336bbb4
> compiler:       Debian clang version 15.0.7, GNU ld (GNU Binutils for Debian) 2.35.2
>
> Unfortunately, I don't have any reproducer for this issue yet.
>
> Downloadable assets:
> disk image: https://storage.googleapis.com/syzbot-assets/7b23da6a6f6c/disk-533925cb.raw.xz
> vmlinux: https://storage.googleapis.com/syzbot-assets/f163e9ea9946/vmlinux-533925cb.xz
> kernel image: https://storage.googleapis.com/syzbot-assets/5b943aa5a1e1/bzImage-533925cb.xz
>
> IMPORTANT: if you fix the issue, please add the following tag to the commit:
> Reported-by: syzbot+ae97a827ae1c3336bbb4@xxxxxxxxxxxxxxxxxxxxxxxxx

#syz test: https://github.com/adam900710/linux graceful_reloc_mismatch

> assertion failed: root->reloc_root == reloc_root, in fs/btrfs/relocation.c:1919
> ------------[ cut here ]------------
> kernel BUG at fs/btrfs/relocation.c:1919!
> invalid opcode: 0000 [#1] PREEMPT SMP KASAN
> CPU: 0 PID: 9904 Comm: syz-executor.3 Not tainted 6.4.0-syzkaller-08881-g533925cb7604 #0
> Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/27/2023
> RIP: 0010:prepare_to_merge+0xbb2/0xc40 fs/btrfs/relocation.c:1919
> Code: fe e9 f5 f7 ff ff e8 6d 62 ec fd 48 c7 c7 20 5e 4b 8b 48 c7 c6 c0 6d 4b 8b 48 c7 c2 a0 5e 4b 8b b9 7f 07 00 00 e8 8e d8 15 07 <0f> 0b e8 d7 17 18 07 f3 0f 1e fa e8 3e 62 ec fd 43 80 3c 2f 00 74
> RSP: 0018:ffffc9000325f760 EFLAGS: 00010246
> RAX: 000000000000004f RBX: ffff888075644030 RCX: 1481ccc522da5800
> RDX: ffffc90005c09000 RSI: 00000000000364ca RDI: 00000000000364cb
> RBP: ffffc9000325f870 R08: ffffffff816f33ac R09: 1ffff9200064bea0
> R10: dffffc0000000000 R11: fffff5200064bea1 R12: ffff888075644000
> R13: ffff88803b166000 R14: ffff88803b166560 R15: ffff88803b166558
> FS:  00007f4e305fd700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000056080679c000 CR3: 00000000193ad000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
> Call Trace:
>   <TASK>
>   relocate_block_group+0xa5d/0xcd0 fs/btrfs/relocation.c:3749
>   btrfs_relocate_block_group+0x7ab/0xd70 fs/btrfs/relocation.c:4087
>   btrfs_relocate_chunk+0x12c/0x3b0 fs/btrfs/volumes.c:3283
>   __btrfs_balance+0x1b06/0x2690 fs/btrfs/volumes.c:4018
>   btrfs_balance+0xbdb/0x1120 fs/btrfs/volumes.c:4402
>   btrfs_ioctl_balance+0x496/0x7c0 fs/btrfs/ioctl.c:3604
>   vfs_ioctl fs/ioctl.c:51 [inline]
>   __do_sys_ioctl fs/ioctl.c:870 [inline]
>   __se_sys_ioctl+0xf8/0x170 fs/ioctl.c:856
>   do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>   do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80
>   entry_SYSCALL_64_after_hwframe+0x63/0xcd
> RIP: 0033:0x7f4e2f88c389
> Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 f1 19 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 b8 ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f4e305fd168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 00007f4e2f9abf80 RCX: 00007f4e2f88c389
> RDX: 00000000200003c0 RSI: 00000000c4009420 RDI: 0000000000000005
> RBP: 00007f4e2f8d7493 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
> R13: 00007ffdbefc213f R14: 00007f4e305fd300 R15: 0000000000022000
>   </TASK>
> Modules linked in:
> ---[ end trace 0000000000000000 ]---
> RIP: 0010:prepare_to_merge+0xbb2/0xc40 fs/btrfs/relocation.c:1919
> Code: fe e9 f5 f7 ff ff e8 6d 62 ec fd 48 c7 c7 20 5e 4b 8b 48 c7 c6 c0 6d 4b 8b 48 c7 c2 a0 5e 4b 8b b9 7f 07 00 00 e8 8e d8 15 07 <0f> 0b e8 d7 17 18 07 f3 0f 1e fa e8 3e 62 ec fd 43 80 3c 2f 00 74
> RSP: 0018:ffffc9000325f760 EFLAGS: 00010246
> RAX: 000000000000004f RBX: ffff888075644030 RCX: 1481ccc522da5800
> RDX: ffffc90005c09000 RSI: 00000000000364ca RDI: 00000000000364cb
> RBP: ffffc9000325f870 R08: ffffffff816f33ac R09: 1ffff9200064bea0
> R10: dffffc0000000000 R11: fffff5200064bea1 R12: ffff888075644000
> R13: ffff88803b166000 R14: ffff88803b166560 R15: ffff88803b166558
> FS:  00007f4e305fd700(0000) GS:ffff8880b9800000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 000055555657e888 CR3: 00000000193ad000 CR4: 00000000003506f0
> DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
> DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
>
>
> ---
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>
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>
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