INFO: task syz.0.791:15916 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.791 state:D stack:24936 pid:15916 tgid:15913 ppid:9918 task_flags:0x400140 flags:0x00004006
Call Trace:
context_switch kernel/sched/core.c:5357 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6961
__schedule_loop kernel/sched/core.c:7043 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7058
schedule_timeout+0x9a/0x270 kernel/time/sleep_timeout.c:75
do_wait_for_common kernel/sched/completion.c:100 [inline]
__wait_for_common kernel/sched/completion.c:121 [inline]
wait_for_common kernel/sched/completion.c:132 [inline]
wait_for_completion+0x2bf/0x5d0 kernel/sched/completion.c:153
kthread_flush_worker+0x1c6/0x240 kernel/kthread.c:1564
__alloc_workqueue+0x146b/0x1b70 kernel/workqueue.c:5763
alloc_workqueue_noprof+0xd4/0x210 kernel/workqueue.c:5786
btrfs_alloc_ordered_workqueue+0x1c3/0x290 fs/btrfs/async-thread.c:140
btrfs_init_workqueues+0x3f0/0x6c0 fs/btrfs/disk-io.c:1997
open_ctree+0x11ef/0x3a10 fs/btrfs/disk-io.c:3424
btrfs_fill_super fs/btrfs/super.c:977 [inline]
btrfs_get_tree_super fs/btrfs/super.c:1940 [inline]
btrfs_get_tree_subvol fs/btrfs/super.c:2077 [inline]
btrfs_get_tree+0xf55/0x1820 fs/btrfs/super.c:2111
vfs_get_tree+0x92/0x2b0 fs/super.c:1815
do_new_mount+0x2a2/0x9e0 fs/namespace.c:3808
do_mount fs/namespace.c:4136 [inline]
__do_sys_mount fs/namespace.c:4347 [inline]
__se_sys_mount+0x317/0x410 fs/namespace.c:4324
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f429d4e038a
RSP: 002b:00007f429b73de68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f429b73def0 RCX: 00007f429d4e038a
RDX: 0000200000000000 RSI: 00002000000015c0 RDI: 00007f429b73deb0
RBP: 0000200000000000 R08: 00007f429b73def0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00002000000015c0
R13: 00007f429b73deb0 R14: 000000000000559e R15: 0000200000001600
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8d9a8b80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
11 locks held by kworker/u8:3/57:
9 locks held by kworker/u8:5/155:
10 locks held by kworker/u8:6/1168:
3 locks held by kworker/u8:10/1377:
3 locks held by kworker/u8:15/1544:
#0: ffff88805cfd5138 ((wq_completion)loop7){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline]
#0: ffff88805cfd5138 ((wq_completion)loop7){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319
#1: ffffc900059efbc0 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline]
#1: ffffc900059efbc0 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319
#2: ffff888024af6160 (&lo->lo_work_lock){+.+.}-{3:3}, at: spin_lock_irq include/linux/spinlock_rt.h:93 [inline]
#2: ffff888024af6160 (&lo->lo_work_lock){+.+.}-{3:3}, at: loop_process_work+0xf8/0x1060 drivers/block/loop.c:1941
2 locks held by getty/5599:
#0: ffff88823bf408a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1410 drivers/tty/n_tty.c:2222
1 lock held by syz-executor/7072:
#0: ffff88805f3120d0 (&type->s_umount_key#59){++++}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff88805f3120d0 (&type->s_umount_key#59){++++}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff88805f3120d0 (&type->s_umount_key#59){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:506
1 lock held by udevd/10054:
4 locks held by udevd/10125:
1 lock held by syz.0.791/15916:
#0: ffff8880358600d0 (&type->s_umount_key#58/1){+.+.}-{4:4}, at: alloc_super+0x204/0x990 fs/super.c:345
12 locks held by syz.1.942/18434:
1 lock held by udevadm/18509:
2 locks held by udevadm/18526:
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120
nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline]
watchdog+0xf93/0xfe0 kernel/hung_task.c:491
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 57 Comm: kworker/u8:3 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Workqueue: btrfs-qgroup-rescan btrfs_work_helper
RIP: 0010:check_prev_add kernel/locking/lockdep.c:-1 [inline]
RIP: 0010:check_prevs_add kernel/locking/lockdep.c:3284 [inline]
RIP: 0010:validate_chain+0x18f5/0x2140 kernel/locking/lockdep.c:3908
Code: 8d 48 c7 c6 d0 66 11 8d e8 58 df e6 ff 90 0f 0b 90 90 90 31 c0 48 8b 3c 24 48 83 c0 30 49 39 c7 0f 84 5a 01 00 00 49 8b 5f 10 <41> 8b 44 24 f8 25 ff 1f 00 00 48 0f a3 05 c9 33 61 11 0f 82 5a ff
RSP: 0000:ffffc9000123e638 EFLAGS: 00000006
RAX: ffffffff929eb520 RBX: ffffffff92a1aea8 RCX: 0000000000000003
RDX: 0000000000030000 RSI: 0000000000000000 RDI: ffff888019fbbb80
RBP: 0000000000000000 R08: ffffc9000123e600 R09: 0000000000000020
R10: 0000000000000100 R11: ffffffff819c6180 R12: ffff888019fbc7e0
R13: ffff888019fbc6a0 R14: ffff888019fbc7e0 R15: ffffffff9586a9d8
FS: 0000000000000000(0000) GS:ffff8881268c2000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6506520000 CR3: 0000000041b30000 CR4: 00000000003526f0
Call Trace:
__lock_acquire+0xab9/0xd20 kernel/locking/lockdep.c:5237
lock_acquire+0x120/0x360 kernel/locking/lockdep.c:5868
rt_spin_lock+0x88/0x2c0 kernel/locking/spinlock_rt.c:56
spin_lock include/linux/spinlock_rt.h:44 [inline]
___slab_alloc+0x25c/0xdd0 mm/slub.c:3768
__slab_alloc mm/slub.c:3981 [inline]
__slab_alloc_node mm/slub.c:4056 [inline]
slab_alloc_node mm/slub.c:4217 [inline]
kmem_cache_alloc_noprof+0xe6/0x310 mm/slub.c:4236
__alloc_extent_buffer+0x31/0x210 fs/btrfs/extent_io.c:2879
alloc_extent_buffer+0x249/0x2a50 fs/btrfs/extent_io.c:3294
btrfs_init_new_buffer fs/btrfs/extent-tree.c:5060 [inline]
btrfs_alloc_tree_block+0x249/0x1290 fs/btrfs/extent-tree.c:5173
btrfs_force_cow_block+0x578/0x2460 fs/btrfs/ctree.c:517
btrfs_cow_block+0x40a/0x9a0 fs/btrfs/ctree.c:699
btrfs_search_slot+0xd17/0x2ba0 fs/btrfs/ctree.c:2097
update_qgroup_info_item fs/btrfs/qgroup.c:882 [inline]
btrfs_run_qgroups+0x347/0x730 fs/btrfs/qgroup.c:3108
commit_cowonly_roots+0x1fc/0x860 fs/btrfs/transaction.c:1354
btrfs_commit_transaction+0xfc7/0x3950 fs/btrfs/transaction.c:2462
btrfs_qgroup_rescan_worker+0x1907/0x2290 fs/btrfs/qgroup.c:3830
btrfs_work_helper+0x398/0xc00 fs/btrfs/async-thread.c:312
process_one_work kernel/workqueue.c:3236 [inline]
process_scheduled_works+0xade/0x17b0 kernel/workqueue.c:3319
worker_thread+0x8a0/0xda0 kernel/workqueue.c:3400
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x3fc/0x770 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245