syzbot

ffff8880913f55b0: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00  ................
XFS (loop4): metadata I/O error: block 0x2 ("xfs_trans_read_buf_map") error 117 numblks 1
XFS (loop4): xfs_imap_lookup: xfs_ialloc_read_agi() returned error -117, agno 0
XFS (loop4): failed to read root inode
------------[ cut here ]------------
WARNING: CPU: 0 PID: 12759 at fs/ext4/inode.c:5253 ext4_write_inode+0x3a0/0x450 fs/ext4/inode.c:5253
Kernel panic - not syncing: panic_on_warn set ...

CPU: 0 PID: 12759 Comm: xfsaild/loop4 Not tainted 4.14.171-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x142/0x197 lib/dump_stack.c:58
 panic+0x1f9/0x42d kernel/panic.c:183
 __warn.cold+0x2f/0x2f kernel/panic.c:547
 report_bug+0x216/0x254 lib/bug.c:186
 fixup_bug arch/x86/kernel/traps.c:177 [inline]
 fixup_bug arch/x86/kernel/traps.c:172 [inline]
 do_error_trap+0x1bb/0x310 arch/x86/kernel/traps.c:295
 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:314
 invalid_op+0x1b/0x40 arch/x86/entry/entry_64.S:963
RIP: 0010:ext4_write_inode+0x3a0/0x450 fs/ext4/inode.c:5253
RSP: 0018:ffff8880427ef730 EFLAGS: 00010297
RAX: ffff88808c67a4c0 RBX: 1ffff110084fdee7 RCX: ffff88808c67ad40
RDX: 0000000000000000 RSI: ffff8880427ef898 RDI: ffff88808c67a4e4
RBP: ffff8880427ef7c0 R08: ffff88808c67a4c0 R09: 0000000000000003
R10: 0000000000000000 R11: ffff88808c67a4c0 R12: ffff8880942135b0
R13: dffffc0000000000 R14: ffff8880427ef798 R15: ffff88808c67a4c0
 write_inode fs/fs-writeback.c:1227 [inline]
 __writeback_single_inode+0xb44/0x1120 fs/fs-writeback.c:1426
 writeback_single_inode+0x1fa/0x380 fs/fs-writeback.c:1480
 sync_inode fs/fs-writeback.c:2508 [inline]
 sync_inode_metadata+0x8c/0xb0 fs/fs-writeback.c:2528
 __generic_file_fsync+0x130/0x1a0 fs/libfs.c:992
 ext4_sync_file+0x755/0x12d0 fs/ext4/fsync.c:120
 vfs_fsync_range+0x10e/0x260 fs/sync.c:196
 generic_write_sync include/linux/fs.h:2677 [inline]
 ext4_file_write_iter+0x68a/0xe90 fs/ext4/file.c:279
 call_write_iter include/linux/fs.h:1777 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x4a7/0x6b0 fs/read_write.c:482
 __kernel_write+0xfc/0x370 fs/read_write.c:501
 do_acct_process+0xc66/0x10b0 kernel/acct.c:520
 slow_acct_process kernel/acct.c:579 [inline]
 acct_process+0x3a5/0x43d kernel/acct.c:605
 do_exit+0x17d5/0x2cd0 kernel/exit.c:848
 kthread+0x2d2/0x430 kernel/kthread.c:234
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Kernel Offset: disabled
Rebooting in 86400 seconds..