EXT4-fs error (device loop4): ext4_orphan_get:1396: comm syz.4.17323: couldn't read orphan inode 15 (err -117)
EXT4-fs (loop4): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: none.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Tainted: G             L     
------------------------------------------------------
syz.4.17323/16793 is trying to acquire lock:
ffff8881b911ce40 (&mm->mmap_lock){++++}-{4:4}, at: __might_fault+0xaf/0x130

but task is already holding lock:
ffff88811977f760 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: ext4_fiemap+0x41/0x330

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #4 (&type->i_mutex_dir_key#3){++++}-{4:4}:
       down_read+0x47/0x2e0
       lookup_slow+0x46/0x70
       path_lookupat+0x3f5/0x8c0
       filename_lookup+0x256/0x5d0
       kern_path+0x35/0x50
       device_list_add+0xfcb/0x2250
       btrfs_scan_one_device+0x3ef/0x670
       btrfs_control_ioctl+0x128/0x360
       __se_sys_ioctl+0xfc/0x170
       do_syscall_64+0xe2/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (&fs_devs->device_list_mutex){+.+.}-{4:4}:
       __mutex_lock+0x19f/0x1340
       btrfs_create_pending_block_groups+0x61d/0x1870
       __btrfs_end_transaction+0x140/0x640
       btrfs_inc_block_group_ro+0x63e/0x6f0
       btrfs_relocate_block_group+0x3f1/0xc70
       btrfs_relocate_chunk+0x12f/0x5c0
       __btrfs_balance+0x1921/0x2520
       btrfs_balance+0xac2/0x11b0
       btrfs_ioctl_balance+0x3d3/0x610
       __se_sys_ioctl+0xfc/0x170
       do_syscall_64+0xe2/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (btrfs_trans_num_extwriters){++++}-{0:0}:
       join_transaction+0x1a4/0xd60
       start_transaction+0x6b6/0x15f0
       btrfs_dirty_inode+0x9f/0x190
       touch_atime+0x2f9/0x6d0
       filemap_read+0x1053/0x1230
       __kernel_read+0x504/0x9b0
       integrity_kernel_read+0x89/0xd0
       ima_calc_file_hash+0x12c3/0x17f0
       ima_collect_measurement+0x48b/0x930
       process_measurement+0x12e0/0x1cb0
       ima_file_check+0xdf/0x130
       security_file_post_open+0xb3/0x260
       path_openat+0x34cb/0x3e20
       do_filp_open+0x22d/0x490
       do_sys_openat2+0x12f/0x220
       __x64_sys_openat+0x138/0x170
       do_syscall_64+0xe2/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (btrfs_trans_num_writers){++++}-{0:0}:
       lock_release+0x199/0x3a0
       sb_end_intwrite+0x26/0x1c0
       __btrfs_end_transaction+0x248/0x640
       btrfs_dirty_inode+0x14c/0x190
       touch_atime+0x2f9/0x6d0
       btrfs_file_mmap_prepare+0x176/0x1f0
       mmap_region+0xc52/0x1eb0
       do_mmap+0xc39/0x10c0
       vm_mmap_pgoff+0x2c9/0x4f0
       ksys_mmap_pgoff+0x51e/0x760
       do_syscall_64+0xe2/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&mm->mmap_lock){++++}-{4:4}:
       __lock_acquire+0x15a5/0x2cf0
       lock_acquire+0x106/0x330
       __might_fault+0xcb/0x130
       _copy_to_user+0x2c/0xb0
       fiemap_fill_next_extent+0x1dd/0x3c0
       iomap_fiemap+0x498/0x580
       ext4_fiemap+0x285/0x330
       do_vfs_ioctl+0x125a/0x1530
       __se_sys_ioctl+0x82/0x170
       do_syscall_64+0xe2/0xf80
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &mm->mmap_lock --> &fs_devs->device_list_mutex --> &type->i_mutex_dir_key#3

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(&type->i_mutex_dir_key#3);
                               lock(&fs_devs->device_list_mutex);
                               lock(&type->i_mutex_dir_key#3);
  rlock(&mm->mmap_lock);

 *** DEADLOCK ***

1 lock held by syz.4.17323/16793:
 #0: ffff88811977f760 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: ext4_fiemap+0x41/0x330

stack backtrace:
CPU: 0 UID: 0 PID: 16793 Comm: syz.4.17323 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: QEMU Standard PC (Q35 + ICH9, 2009), BIOS 1.16.2-debian-1.16.2-1 04/01/2014
Call Trace:
 <TASK>
 dump_stack_lvl+0xe8/0x150
 print_circular_bug+0x2e1/0x300
 check_noncircular+0x12e/0x150
 __lock_acquire+0x15a5/0x2cf0
 lock_acquire+0x106/0x330
 __might_fault+0xcb/0x130
 _copy_to_user+0x2c/0xb0
 fiemap_fill_next_extent+0x1dd/0x3c0
 iomap_fiemap+0x498/0x580
 ext4_fiemap+0x285/0x330
 do_vfs_ioctl+0x125a/0x1530
 __se_sys_ioctl+0x82/0x170
 do_syscall_64+0xe2/0xf80
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f1345f9acb9
Code: ff c3 66 2e 0f 1f 84 00 00 00 00 00 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 e8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007f1346dda028 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f1346215fa0 RCX: 00007f1345f9acb9
RDX: 0000200000000040 RSI: 00000000c020660b RDI: 0000000000000004
RBP: 00007f1346008bf7 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f1346216038 R14: 00007f1346215fa0 R15: 00007ffedec98e38
 </TASK>
