Re: WARNING in _btrfs_ioctl_set_received_subvol

[Wei Chen <harperchen1110@gmail.com>]

Dear Linux developers,

I hope the following bug report is helpful.

Best,
Wei

On Sun, 13 Nov 2022 at 19:38, Wei Chen <harperchen1110@gmail.com> wrote:
>
> Dear Linux Developer,
>
> Recently when using our tool to fuzz kernel, the following crash was
> triggered. The bug persists in Linux 6.0.
>
> HEAD commit:  4f5365f77018  Linux 5.15.76
> git tree: stable
> compiler: gcc 7.5.0
> console output:
> https://drive.google.com/file/d/1wkzu8jz6edriSP6TpsCGYD5AzkLajIEv/view?usp=share_link
> kernel config: https://drive.google.com/file/d/1flhc33savDkmYN6PRU5C2vXDX0LAKMvM/view?usp=share_link
> C reproducer: https://drive.google.com/file/d/1zKWsWAOcaHfPKewTG6P3pnnVfwH_WXa9/view?usp=share_link
> Syz reproducer:
> https://drive.google.com/file/d/1jUR8_6Re4xpJhyLdXqPiiV72WT-Tk8A-/view?usp=share_link
>
> IMPORTANT: if you fix the bug, please add the following tag to the commit:
> Reported-by: Wei Chen <harperchen1110@gmail.com>
>
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000007
> R13: 0000000000000000 R14: 000000000077bf80 R15: 00007ffd3c817900
>  </TASK>
> ------------[ cut here ]------------
> WARNING: CPU: 1 PID: 29222 at fs/btrfs/ioctl.c:4521
> _btrfs_ioctl_set_received_subvol+0x221/0x430 fs/btrfs/ioctl.c:4521
> Modules linked in:
> CPU: 1 PID: 29222 Comm: syz-executor.0 Not tainted 5.15.76 #5
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS
> rel-1.13.0-48-gd9c812dda519-prebuilt.qemu.org 04/01/2014
> RIP: 0010:_btrfs_ioctl_set_received_subvol+0x221/0x430 fs/btrfs/ioctl.c:4521
> Code: e8 74 34 44 ff 83 fb fb 0f 84 de 01 00 00 83 fb e2 0f 84 d5 01
> 00 00 e8 5d 34 44 ff 89 de 48 c7 c7 c0 f8 39 85 e8 9f dc 2e ff <0f> 0b
> e8 48 34 44 ff 89 d9 ba a9 11 00 00 e9 45 01 00 00 49 8b 4f
> RSP: 0018:ffffc9000aecfd40 EFLAGS: 00010286
> RAX: 0000000000000000 RBX: fffffffffffffff4 RCX: ffffc900013ed000
> RDX: 0000000000040000 RSI: ffffffff812d935c RDI: 00000000ffffffff
> RBP: ffffc9000aecfda0 R08: 0000000000000000 R09: 0000000000000001
> R10: ffffc9000aecfbe0 R11: 0000000000000003 R12: ffff888014210400
> R13: ffff8880208d2000 R14: ffff88810c4f21c0 R15: ffff88810f37b600
> FS:  00007f41ffc27700(0000) GS:ffff88813dc00000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 00007fab915f7008 CR3: 000000002096e000 CR4: 00000000003526e0
> Call Trace:
>  <TASK>
>  btrfs_ioctl_set_received_subvol_32 fs/btrfs/ioctl.c:4584 [inline]
>  btrfs_ioctl+0x2154/0x3d50 fs/btrfs/ioctl.c:5007
>  vfs_ioctl fs/ioctl.c:51 [inline]
>  __do_sys_ioctl fs/ioctl.c:874 [inline]
>  __se_sys_ioctl fs/ioctl.c:860 [inline]
>  __x64_sys_ioctl+0xb6/0x100 fs/ioctl.c:860
>  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
>  do_syscall_64+0x34/0xb0 arch/x86/entry/common.c:80
>  entry_SYSCALL_64_after_hwframe+0x61/0xcb
> RIP: 0033:0x4697f9
> Code: f7 d8 64 89 02 b8 ff ff ff ff c3 66 0f 1f 44 00 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 bc ff ff ff f7 d8 64 89 01 48
> RSP: 002b:00007f41ffc26c48 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
> RAX: ffffffffffffffda RBX: 000000000077bf80 RCX: 00000000004697f9
> RDX: 0000000020072c40 RSI: 00000000c0c09425 RDI: 0000000000000005
> RBP: 00007f41ffc26c80 R08: 0000000000000000 R09: 0000000000000000
> R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000007
> R13: 0000000000000000 R14: 000000000077bf80 R15: 00007ffd3c817900
>  </TASK>
>
> Best,
> Wei