BTRFS warning (device loop0): excessive commit interval 622039222
BTRFS info (device loop0): force zlib compression, level 3
BTRFS info (device loop0): using free space tree
BTRFS info (device loop0): has skinny extents
======================================================
WARNING: possible circular locking dependency detected
4.19.211-syzkaller #0 Not tainted
------------------------------------------------------
syz-executor601/8083 is trying to acquire lock:
000000001e26bab2 (sb_internal#2){.+.+}, at: sb_start_intwrite include/linux/fs.h:1626 [inline]
000000001e26bab2 (sb_internal#2){.+.+}, at: start_transaction+0xa37/0xf90 fs/btrfs/transaction.c:528

but task is already holding lock:
000000008a908178 (&fs_info->qgroup_ioctl_lock){+.+.}, at: btrfs_quota_enable+0xbf/0x10b0 fs/btrfs/qgroup.c:893

which lock already depends on the new lock.


the existing dependency chain (in reverse order) is:

-> #1 (&fs_info->qgroup_ioctl_lock){+.+.}:
       btrfs_create_qgroup+0x5a/0x270 fs/btrfs/qgroup.c:1380
       btrfs_ioctl_qgroup_create fs/btrfs/ioctl.c:5335 [inline]
       btrfs_ioctl+0xcce/0x76d0 fs/btrfs/ioctl.c:6025
       vfs_ioctl fs/ioctl.c:46 [inline]
       file_ioctl fs/ioctl.c:501 [inline]
       do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
       ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
       __do_sys_ioctl fs/ioctl.c:712 [inline]
       __se_sys_ioctl fs/ioctl.c:710 [inline]
       __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
       do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

-> #0 (sb_internal#2){.+.+}:
       percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline]
       percpu_down_read include/linux/percpu-rwsem.h:59 [inline]
       __sb_start_write+0x6e/0x2a0 fs/super.c:1366
       sb_start_intwrite include/linux/fs.h:1626 [inline]
       start_transaction+0xa37/0xf90 fs/btrfs/transaction.c:528
       btrfs_quota_enable+0x169/0x10b0 fs/btrfs/qgroup.c:905
       btrfs_ioctl_quota_ctl fs/btrfs/ioctl.c:5233 [inline]
       btrfs_ioctl+0x622c/0x76d0 fs/btrfs/ioctl.c:6021
       vfs_ioctl fs/ioctl.c:46 [inline]
       file_ioctl fs/ioctl.c:501 [inline]
       do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
       ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
       __do_sys_ioctl fs/ioctl.c:712 [inline]
       __se_sys_ioctl fs/ioctl.c:710 [inline]
       __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
       do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
       entry_SYSCALL_64_after_hwframe+0x49/0xbe

other info that might help us debug this:

 Possible unsafe locking scenario:

       CPU0                    CPU1
       ----                    ----
  lock(&fs_info->qgroup_ioctl_lock);
                               lock(sb_internal#2);
                               lock(&fs_info->qgroup_ioctl_lock);
  lock(sb_internal#2);

 *** DEADLOCK ***

3 locks held by syz-executor601/8083:
 #0: 0000000018b667d7 (sb_writers#11){.+.+}, at: sb_start_write include/linux/fs.h:1579 [inline]
 #0: 0000000018b667d7 (sb_writers#11){.+.+}, at: mnt_want_write_file+0x63/0x1d0 fs/namespace.c:418
 #1: 000000007bb2a53e (&fs_info->subvol_sem){+.+.}, at: btrfs_ioctl_quota_ctl fs/btrfs/ioctl.c:5229 [inline]
 #1: 000000007bb2a53e (&fs_info->subvol_sem){+.+.}, at: btrfs_ioctl+0x3d12/0x76d0 fs/btrfs/ioctl.c:6021
 #2: 000000008a908178 (&fs_info->qgroup_ioctl_lock){+.+.}, at: btrfs_quota_enable+0xbf/0x10b0 fs/btrfs/qgroup.c:893

stack backtrace:
CPU: 0 PID: 8083 Comm: syz-executor601 Not tainted 4.19.211-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2ef lib/dump_stack.c:118
 print_circular_bug.constprop.0.cold+0x2d7/0x41e kernel/locking/lockdep.c:1222
 check_prev_add kernel/locking/lockdep.c:1866 [inline]
 check_prevs_add kernel/locking/lockdep.c:1979 [inline]
 validate_chain kernel/locking/lockdep.c:2420 [inline]
 __lock_acquire+0x30c9/0x3ff0 kernel/locking/lockdep.c:3416
 lock_acquire+0x170/0x3c0 kernel/locking/lockdep.c:3908
 percpu_down_read_preempt_disable include/linux/percpu-rwsem.h:36 [inline]
 percpu_down_read include/linux/percpu-rwsem.h:59 [inline]
 __sb_start_write+0x6e/0x2a0 fs/super.c:1366
 sb_start_intwrite include/linux/fs.h:1626 [inline]
 start_transaction+0xa37/0xf90 fs/btrfs/transaction.c:528
 btrfs_quota_enable+0x169/0x10b0 fs/btrfs/qgroup.c:905
 btrfs_ioctl_quota_ctl fs/btrfs/ioctl.c:5233 [inline]
 btrfs_ioctl+0x622c/0x76d0 fs/btrfs/ioctl.c:6021
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcdb/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x7fbf0298a5e9
Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 e1 14 00 00 90 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 c0 ff ff ff f7 d8 64 89 01 48
RSP: 002b:00007ffdb8206158 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fbf0298a5e9
RDX: 00000000200000c0 RSI: 00000000c0109428 RDI: 0000000000000005
RBP: 0000000000000000 R08: 00007fbf029fcec0 R09: 00007fbf029fcec0
R10: 00007fbf029fcec0 R11: 0000000000000246 R12: 00007ffdb8206180
R13: 0000000000000000 R14: 431bde82d7b634db R15: 0000000000000000
BTRFS error (device loop0): fail to start transaction for status update: -28