[ OK ] Reached target Graphical Interface. Starting Update UTMP about System Runlevel Changes... Starting Load/Save RF Kill Switch Status... [ OK ] Started Update UTMP about System Runlevel Changes. [ OK ] Started Load/Save RF Kill Switch Status. Debian GNU/Linux 9 syzkaller ttyS0 Warning: Permanently added '10.128.1.153' (ECDSA) to the list of known hosts. executing program syzkaller login: [ 35.136717] BTRFS: device fsid 24c7a497-3402-47dd-bef8-82358f5f30e0 devid 1 transid 8 /dev/loop0 [ 35.160994] BTRFS info (device loop0): using free space tree [ 35.166895] BTRFS info (device loop0): has skinny extents [ 35.224513] [ 35.226152] ====================================================== [ 35.229691] BTRFS error (device loop0): fail to start transaction for status update: -28 [ 35.232447] WARNING: possible circular locking dependency detected [ 35.246948] 4.19.211-syzkaller #0 Not tainted [ 35.251422] ------------------------------------------------------ [ 35.257718] syz-executor617/8091 is trying to acquire lock: [ 35.263399] 0000000023f8737c (&fs_info->qgroup_ioctl_lock){+.+.}, at: btrfs_remove_qgroup+0xae/0x770 [ 35.272652] [ 35.272652] but task is already holding lock: [ 35.278596] 00000000e5f765a0 (sb_internal#2){.+.+}, at: start_transaction+0xa37/0xf90 [ 35.286545] [ 35.286545] which lock already depends on the new lock. [ 35.286545] [ 35.294835] [ 35.294835] the existing dependency chain (in reverse order) is: [ 35.302430] [ 35.302430] -> #1 (sb_internal#2){.+.+}: [ 35.308193] start_transaction+0xa37/0xf90 [ 35.312946] btrfs_quota_enable+0x169/0x10b0 [ 35.317865] btrfs_ioctl+0x622c/0x76d0 [ 35.322258] do_vfs_ioctl+0xcdb/0x12e0 [ 35.326645] ksys_ioctl+0x9b/0xc0 [ 35.330594] __x64_sys_ioctl+0x6f/0xb0 [ 35.334980] do_syscall_64+0xf9/0x620 [ 35.339279] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.344961] [ 35.344961] -> #0 (&fs_info->qgroup_ioctl_lock){+.+.}: [ 35.351706] __mutex_lock+0xd7/0x1190 [ 35.356008] btrfs_remove_qgroup+0xae/0x770 [ 35.360830] btrfs_ioctl+0x661c/0x76d0 [ 35.365216] do_vfs_ioctl+0xcdb/0x12e0 [ 35.369601] ksys_ioctl+0x9b/0xc0 [ 35.373555] __x64_sys_ioctl+0x6f/0xb0 [ 35.377941] do_syscall_64+0xf9/0x620 [ 35.382241] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.387921] [ 35.387921] other info that might help us debug this: [ 35.387921] [ 35.396038] Possible unsafe locking scenario: [ 35.396038] [ 35.402068] CPU0 CPU1 [ 35.406708] ---- ---- [ 35.411344] lock(sb_internal#2); [ 35.414856] lock(&fs_info->qgroup_ioctl_lock); [ 35.422188] lock(sb_internal#2); [ 35.428225] lock(&fs_info->qgroup_ioctl_lock); [ 35.432950] [ 35.432950] *** DEADLOCK *** [ 35.432950] [ 35.438985] 2 locks held by syz-executor617/8091: [ 35.443800] #0: 000000008a3c4cee (sb_writers#11){.+.+}, at: mnt_want_write_file+0x63/0x1d0 [ 35.452277] #1: 00000000e5f765a0 (sb_internal#2){.+.+}, at: start_transaction+0xa37/0xf90 [ 35.460657] [ 35.460657] stack backtrace: [ 35.465129] CPU: 1 PID: 8091 Comm: syz-executor617 Not tainted 4.19.211-syzkaller #0 [ 35.472979] Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022 [ 35.482305] Call Trace: [ 35.484873] dump_stack+0x1fc/0x2ef [ 35.488485] print_circular_bug.constprop.0.cold+0x2d7/0x41e [ 35.494258] __lock_acquire+0x30c9/0x3ff0 [ 35.498383] ? mark_held_locks+0xf0/0xf0 [ 35.502423] ? __bfs.part.0+0x1ce/0x450 [ 35.506375] lock_acquire+0x170/0x3c0 [ 35.510153] ? btrfs_remove_qgroup+0xae/0x770 [ 35.514628] ? btrfs_remove_qgroup+0xae/0x770 [ 35.519101] __mutex_lock+0xd7/0x1190 [ 35.522876] ? btrfs_remove_qgroup+0xae/0x770 [ 35.527350] ? btrfs_record_root_in_trans+0x137/0x190 [ 35.532514] ? btrfs_remove_qgroup+0xae/0x770 [ 35.536987] ? mutex_trylock+0x1a0/0x1a0 [ 35.541025] ? record_root_in_trans.isra.0+0x2db/0x400 [ 35.546276] ? __mutex_unlock_slowpath+0xea/0x610 [ 35.551094] ? wait_for_completion_io+0x10/0x10 [ 35.555738] btrfs_remove_qgroup+0xae/0x770 [ 35.560037] ? btrfs_record_root_in_trans+0x13c/0x190 [ 35.565210] ? btrfs_create_qgroup+0x270/0x270 [ 35.569769] ? start_transaction+0x239/0xf90 [ 35.574156] btrfs_ioctl+0x661c/0x76d0 [ 35.578021] ? lock_downgrade+0x720/0x720 [ 35.582147] ? lock_acquire+0x170/0x3c0 [ 35.586193] ? finish_task_switch+0x118/0x760 [ 35.590664] ? btrfs_ioctl_get_supported_features+0x50/0x50 [ 35.596556] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 35.601112] ? finish_task_switch+0x1db/0x760 [ 35.605581] ? __schedule+0x88f/0x2040 [ 35.609446] ? io_schedule_timeout+0x140/0x140 [ 35.614012] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 35.618746] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 35.623304] ? trace_hardirqs_on_thunk+0x1a/0x1c [ 35.628035] ? retint_kernel+0x2d/0x2d [ 35.631905] ? btrfs_ioctl_get_supported_features+0x50/0x50 [ 35.637590] ? btrfs_ioctl_get_supported_features+0x50/0x50 [ 35.643277] do_vfs_ioctl+0xcdb/0x12e0 [ 35.647141] ? _raw_spin_unlock_irqrestore+0x66/0xe0 [ 35.652218] ? debug_check_no_obj_freed+0x201/0x490 [ 35.657208] ? ioctl_preallocate+0x200/0x200 [ 35.661597] ? putname+0xe1/0x120 [ 35.665053] ? putname+0xe1/0x120 [ 35.668502] ? rcu_read_lock_sched_held+0x16c/0x1d0 [ 35.673493] ? kmem_cache_free+0x226/0x260 [ 35.677705] ? putname+0xe1/0x120 [ 35.681135] ? do_sys_open+0x2bf/0x520 [ 35.684998] ? filp_open+0x70/0x70 [ 35.688513] ksys_ioctl+0x9b/0xc0 [ 35.691950] __x64_sys_ioctl+0x6f/0xb0 [ 35.695815] ? lockdep_hardirqs_on+0x3a8/0x5c0 [ 35.700371] do_syscall_64+0xf9/0x620 [ 35.704146] entry_SYSCALL_64_after_hwframe+0x49/0xbe [ 35.709323] RIP: 0033:0x7efcc9d277f9 [ 35.713013] Code: 28 00 00 00 75 05 48 83 c4 28 c3 e8 51 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