EXT4-fs (loop8): mounted filesystem 00000000-0000-0000-0000-000000000000 r/w without journal. Quota mode: writeback.
ext4 filesystem being mounted at /201/bus supports timestamps until 2038-01-19 (0x7fffffff)
======================================================
WARNING: possible circular locking dependency detected
syzkaller #0 Not tainted
------------------------------------------------------
syz.8.6512/22669 is trying to acquire lock:
ffff8881b408e4a8 (&dquot->dq_lock){+.+.}-{4:4}, at: dqget+0x72a/0xf10

but task is already holding lock:
ffff8881be8b43b8 (&ei->xattr_sem){++++}-{4:4}, at: ext4_xattr_set_handle+0x165/0x1590

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_mknod+0xe93/0x2050
       ocfs2_create+0x1a5/0x440
       path_openat+0x14f4/0x3830
       do_filp_open+0x1fa/0x410
       do_sys_openat2+0x121/0x1c0
       __x64_sys_open+0x11e/0x150
       do_syscall_64+0xfa/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_mknod+0xe93/0x2050
       ocfs2_create+0x1a5/0x440
       path_openat+0x14f4/0x3830
       do_filp_open+0x1fa/0x410
       do_sys_openat2+0x121/0x1c0
       __x64_sys_open+0x11e/0x150
       do_syscall_64+0xfa/0xfa0
       entry_SYSCALL_64_after_hwframe+0x77/0x7f

-> #2 (sb_internal#5){.+.+}-{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_initialize+0x3b3/0xcb0
       __ext4_new_inode+0x7dd/0x3cb0
       ext4_xattr_inode_lookup_create+0xa3f/0x1c20
       ext4_xattr_block_set+0x223/0x2ac0
       ext4_xattr_set_handle+0xdfb/0x1590
       ext4_xattr_set+0x230/0x320
       __vfs_setxattr+0x43c/0x480
       __vfs_setxattr_noperm+0x12d/0x660
       vfs_setxattr+0x16b/0x2f0
       filename_setxattr+0x274/0x600
       path_setxattrat+0x364/0x3a0
       __x64_sys_setxattr+0xbc/0xe0
       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
       ----                    ----
  lock(&ei->xattr_sem);
                               lock(jbd2_handle);
                               lock(&ei->xattr_sem);
  lock(&dquot->dq_lock);

 *** DEADLOCK ***

3 locks held by syz.8.6512/22669:
 #0: ffff8881a9e10420 (sb_writers#4){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90
 #1: ffff8881be8b46d0 (&type->i_mutex_dir_key#3){++++}-{4:4}, at: vfs_setxattr+0x144/0x2f0
 #2: ffff8881be8b43b8 (&ei->xattr_sem){++++}-{4:4}, at: ext4_xattr_set_handle+0x165/0x1590

stack backtrace:
CPU: 1 UID: 0 PID: 22669 Comm: syz.8.6512 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_initialize+0x3b3/0xcb0
 __ext4_new_inode+0x7dd/0x3cb0
 ext4_xattr_inode_lookup_create+0xa3f/0x1c20
 ext4_xattr_block_set+0x223/0x2ac0
 ext4_xattr_set_handle+0xdfb/0x1590
 ext4_xattr_set+0x230/0x320
 __vfs_setxattr+0x43c/0x480
 __vfs_setxattr_noperm+0x12d/0x660
 vfs_setxattr+0x16b/0x2f0
 filename_setxattr+0x274/0x600
 path_setxattrat+0x364/0x3a0
 __x64_sys_setxattr+0xbc/0xe0
 do_syscall_64+0xfa/0xfa0
 entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f7ad158eec9
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:00007f7ad24d2038 EFLAGS: 00000246 ORIG_RAX: 00000000000000bc
RAX: ffffffffffffffda RBX: 00007f7ad17e5fa0 RCX: 00007f7ad158eec9
RDX: 0000200000001400 RSI: 00002000000001c0 RDI: 0000200000000380
RBP: 00007f7ad1611f91 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000835 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f7ad17e6038 R14: 00007f7ad17e5fa0 R15: 00007fff4ffcc098
 </TASK>
