loop8: detected capacity change from 0 to 4096
EXT4-fs (loop8): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.8.1094/10025 is trying to acquire lock:
ffff88801ad66ea8 (&dquot->dq_lock){+.+.}-{4:4}, at: dqget+0x72a/0xf10

but task is already holding lock:
ffff8881ba9f4d48 (&ei->xattr_sem){++++}-{4:4}, at: ext4_setattr+0x855/0x1bc0

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #5 (&ei->xattr_sem){++++}-{4:4}:
       lock_acquire+0x120/0x360
       down_read+0x46/0x2e0
       ext4_setattr+0x855/0x1bc0
       notify_change+0xc1a/0xf40
       chown_common+0x40c/0x5c0
       do_fchownat+0x161/0x270
       __x64_sys_chown+0x82/0xa0
       do_syscall_64+0xfa/0xfa0
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #4 (jbd2_handle){++++}-{0:0}:
       lock_acquire+0x120/0x360
       start_this_handle+0x1fa7/0x21c0
       jbd2__journal_start+0x2c1/0x5b0
       jbd2_journal_start+0x2a/0x40
       ocfs2_start_trans+0x376/0x6d0
       ocfs2_shutdown_local_alloc+0x200/0xa10
       ocfs2_dismount_volume+0x201/0x8d0
       generic_shutdown_super+0x135/0x2c0
       kill_block_super+0x44/0x90
       deactivate_locked_super+0xbc/0x130
       cleanup_mnt+0x425/0x4c0
       task_work_run+0x1d4/0x260
       exit_to_user_mode_loop+0xe9/0x130
       do_syscall_64+0x2bd/0xfa0
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #3 (&journal->j_trans_barrier){.+.+}-{4:4}:
       lock_acquire+0x120/0x360
       down_read+0x46/0x2e0
       ocfs2_start_trans+0x36a/0x6d0
       ocfs2_shutdown_local_alloc+0x200/0xa10
       ocfs2_dismount_volume+0x201/0x8d0
       generic_shutdown_super+0x135/0x2c0
       kill_block_super+0x44/0x90
       deactivate_locked_super+0xbc/0x130
       cleanup_mnt+0x425/0x4c0
       task_work_run+0x1d4/0x260
       exit_to_user_mode_loop+0xe9/0x130
       do_syscall_64+0x2bd/0xfa0
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (sb_internal#3){.+.+}-{0:0}:
       lock_acquire+0x120/0x360
       ocfs2_start_trans+0x26b/0x6d0
       ocfs2_acquire_dquot+0x455/0xb30
       dqget+0x7b1/0xf10
       dquot_set_dqblk+0x2b/0xfa0
       quota_setquota+0x4b7/0x540
       __se_sys_quotactl+0x279/0x950
       do_syscall_64+0xfa/0xfa0
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #1 (&ocfs2_quota_ip_alloc_sem_key){++++}-{4:4}:
       lock_acquire+0x120/0x360
       down_write+0x96/0x1f0
       ocfs2_create_local_dquot+0x19d/0x1a40
       ocfs2_acquire_dquot+0x80f/0xb30
       dqget+0x7b1/0xf10
       dquot_set_dqblk+0x2b/0xfa0
       quota_setquota+0x4b7/0x540
       __se_sys_quotactl+0x279/0x950
       do_syscall_64+0xfa/0xfa0
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #0 (&dquot->dq_lock){+.+.}-{4:4}:
       validate_chain+0xb9b/0x2140
       __lock_acquire+0xab9/0xd20
       lock_acquire+0x120/0x360
       __mutex_lock+0x187/0x1350
       dqget+0x72a/0xf10
       dquot_transfer+0x4b8/0x6d0
       ext4_setattr+0x865/0x1bc0
       notify_change+0xc1a/0xf40
       chown_common+0x40c/0x5c0
       do_fchownat+0x161/0x270
       __x64_sys_lchown+0x85/0xa0
       do_syscall_64+0xfa/0xfa0
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

other info that might help us debug this:

Chain exists of:
  &dquot->dq_lock --> jbd2_handle --> &ei->xattr_sem

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  rlock(&ei->xattr_sem);
                               lock(jbd2_handle);
                               lock(&ei->xattr_sem);
  lock(&dquot->dq_lock);

 *** DEADLOCK ***

3 locks held by syz.8.1094/10025:
 #0: ffff8881160be420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90
 #1: ffff8881ba9f5060 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: chown_common+0x313/0x5c0
 #2: ffff8881ba9f4d48 (&ei->xattr_sem){++++}-{4:4}, at: ext4_setattr+0x855/0x1bc0

stack backtrace:
CPU: 0 UID: 0 PID: 10025 Comm: syz.8.1094 Not tainted syzkaller #0 PREEMPT(full) 
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+0x189/0x250
 print_circular_bug+0x2ee/0x310
 check_noncircular+0x134/0x160
 validate_chain+0xb9b/0x2140
 __lock_acquire+0xab9/0xd20
 lock_acquire+0x120/0x360
 __mutex_lock+0x187/0x1350
 dqget+0x72a/0xf10
 dquot_transfer+0x4b8/0x6d0
 ext4_setattr+0x865/0x1bc0
 notify_change+0xc1a/0xf40
 chown_common+0x40c/0x5c0
 do_fchownat+0x161/0x270
 __x64_sys_lchown+0x85/0xa0
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fe03738efc9
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 a8 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007fe0355f6038 EFLAGS: 00000246 ORIG_RAX: 000000000000005e
RAX: ffffffffffffffda RBX: 00007fe0375e5fa0 RCX: 00007fe03738efc9
RDX: 000000000000ee01 RSI: 0000000000000000 RDI: 0000200000000240
RBP: 00007fe037411f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fe0375e6038 R14: 00007fe0375e5fa0 R15: 00007ffff1ffa678
 </TASK>
