[syzbot] WARNING in __kernel_write_iter

[syzbot]

Hello,

syzbot found the following issue on:

HEAD commit:    a6afa4199d3d Merge tag 'mailbox-v6.1' of git://git.linaro...
git tree:       upstream
console output: https://syzkaller.appspot.com/x/log.txt?x=110f6f0a880000
kernel config:  https://syzkaller.appspot.com/x/.config?x=d19f5d16783f901
dashboard link: https://syzkaller.appspot.com/bug?extid=12e098239d20385264d3
compiler:       Debian clang version 13.0.1-++20220126092033+75e33f71c2da-1~exp1~20220126212112.63, 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/12e24d042ff9/disk-a6afa419.raw.xz
vmlinux: https://storage.googleapis.com/syzbot-assets/4862ae4e2edf/vmlinux-a6afa419.xz

IMPORTANT: if you fix the issue, please add the following tag to the commit:
Reported-by: syzbot+12e098239d20385264d3@xxxxxxxxxxxxxxxxxxxxxxxxx

------------[ cut here ]------------
WARNING: CPU: 1 PID: 20347 at fs/read_write.c:504 __kernel_write_iter+0x639/0x740
Modules linked in:
CPU: 1 PID: 20347 Comm: syz-executor.1 Not tainted 6.0.0-syzkaller-09039-ga6afa4199d3d #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/22/2022
RIP: 0010:__kernel_write_iter+0x639/0x740 fs/read_write.c:504
Code: 25 28 00 00 00 48 3b 84 24 e0 00 00 00 0f 85 17 01 00 00 4c 89 f0 48 8d 65 d8 5b 41 5c 41 5d 41 5e 41 5f 5d c3 e8 07 b0 9e ff <0f> 0b 49 c7 c6 f7 ff ff ff eb a5 e8 f7 af 9e ff 4c 8b 74 24 18 eb
RSP: 0018:ffffc90015997740 EFLAGS: 00010287
RAX: ffffffff81e81fe9 RBX: 00000000000a801d RCX: 0000000000040000
RDX: ffffc90004875000 RSI: 0000000000000c05 RDI: 0000000000000c06
RBP: ffffc90015997870 R08: ffffffff81e81a5d R09: fffffbfff1c19fd6
R10: fffffbfff1c19fd6 R11: 1ffffffff1c19fd5 R12: 1ffff92002b32ef4
R13: 1ffff1100f3c659f R14: ffff888079e32c80 R15: dffffc0000000000
FS:  00007f320c219700(0000) GS:ffff8880b9b00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c023d85000 CR3: 000000007765a000 CR4: 00000000003506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 __kernel_write fs/read_write.c:537 [inline]
 kernel_write+0x1c5/0x340 fs/read_write.c:558
 write_buf fs/btrfs/send.c:590 [inline]
 send_header fs/btrfs/send.c:708 [inline]
 send_subvol+0x1a7/0x4b60 fs/btrfs/send.c:7648
 btrfs_ioctl_send+0x1e34/0x2340 fs/btrfs/send.c:8014
 _btrfs_ioctl_send+0x2e8/0x420 fs/btrfs/ioctl.c:5233
 btrfs_ioctl+0x5eb/0xc10
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:870 [inline]
 __se_sys_ioctl+0xfb/0x170 fs/ioctl.c:856
 do_syscall_x64 arch/x86/entry/common.c:50 [inline]
 do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
 entry_SYSCALL_64_after_hwframe+0x63/0xcd
RIP: 0033:0x7f320b08a5a9
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 b8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f320c219168 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f320b1abf80 RCX: 00007f320b08a5a9
RDX: 0000000020000040 RSI: 0000000040489426 RDI: 0000000000000003
RBP: 00007f320b0e5580 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007ffca50575cf R14: 00007f320c219300 R15: 0000000000022000
 </TASK>


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