INFO: task syz.4.725:12981 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.725 state:D stack:25672 pid:12981 tgid:12980 ppid:8922 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5325 [inline]
__schedule+0x16f3/0x4c20 kernel/sched/core.c:6929
__schedule_loop kernel/sched/core.c:7011 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7026
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+0x1470/0x1b70 kernel/workqueue.c:5795
alloc_workqueue_noprof+0xd4/0x210 kernel/workqueue.c:5818
btrfs_alloc_workqueue+0x1ec/0x2d0 fs/btrfs/async-thread.c:112
btrfs_init_workqueues+0x2c4/0x6c0 fs/btrfs/disk-io.c:1987
open_ctree+0x141d/0x3d20 fs/btrfs/disk-io.c:3426
btrfs_fill_super fs/btrfs/super.c:987 [inline]
btrfs_get_tree_super fs/btrfs/super.c:1951 [inline]
btrfs_get_tree_subvol fs/btrfs/super.c:2088 [inline]
btrfs_get_tree+0xf3c/0x1810 fs/btrfs/super.c:2122
vfs_get_tree+0x92/0x2b0 fs/super.c:1751
fc_mount fs/namespace.c:1208 [inline]
do_new_mount_fc fs/namespace.c:3651 [inline]
do_new_mount+0x302/0xa10 fs/namespace.c:3727
do_mount fs/namespace.c:4050 [inline]
__do_sys_mount fs/namespace.c:4238 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4215
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb3eb7f076a
RSP: 002b:00007fb3e9a4de68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fb3e9a4def0 RCX: 00007fb3eb7f076a
RDX: 00002000000055c0 RSI: 0000200000000180 RDI: 00007fb3e9a4deb0
RBP: 00002000000055c0 R08: 00007fb3e9a4def0 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000200000000180
R13: 00007fb3e9a4deb0 R14: 000000000000559d R15: 0000200000000440
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8d7aa4c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by kworker/u8:3/58:
2 locks held by getty/5556:
#0: ffff8880302ee0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e7e2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1400 drivers/tty/n_tty.c:2222
3 locks held by kworker/1:5/5870:
2 locks held by kworker/u8:10/8219:
#0: ffff88813fe29938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff88813fe29938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc90003ea7ba0 (connector_reaper_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc90003ea7ba0 (connector_reaper_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
1 lock held by syz-executor/8887:
#0: ffffffff8d40c0a8 (tasklist_lock){++++}-{3:3}, at: read_lock include/linux/rwlock_rt.h:37 [inline]
#0: ffffffff8d40c0a8 (tasklist_lock){++++}-{3:3}, at: __do_wait+0xe1/0x740 kernel/exit.c:1667
1 lock held by syz-executor/8890:
1 lock held by udevd/9100:
#0: ffff888148cefb68 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:995 [inline]
#0: ffff888148cefb68 (&sb->s_type->i_mutex_key#7){++++}-{4:4}, at: blkdev_read_iter+0x2ff/0x440 block/fops.c:858
2 locks held by udevd/9144:
7 locks held by udevd/9862:
1 lock held by syz-executor/10627:
#0: ffffffff8d40c0a8 (tasklist_lock){++++}-{3:3}, at: read_lock include/linux/rwlock_rt.h:37 [inline]
#0: ffffffff8d40c0a8 (tasklist_lock){++++}-{3:3}, at: __do_wait+0xe1/0x740 kernel/exit.c:1667
1 lock held by syz.4.725/12981:
#0: ffff888052dda0d0 (&type->s_umount_key#56/1){+.+.}-{4:4}, at: alloc_super+0x1ba/0x9a0 fs/super.c:344
10 locks held by syz-executor/13259:
2 locks held by syz.7.991/15686:
4 locks held by syz.1.992/15688:
6 locks held by dhcpcd-run-hook/15693:
=============================================
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 10/02/2025
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:332 [inline]
watchdog+0xf60/0xfa0 kernel/hung_task.c:495
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x4bc/0x870 arch/x86/kernel/process.c:158
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: 15686 Comm: syz.7.991 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/02/2025
RIP: 0010:rcu_is_watching_curr_cpu include/linux/context_tracking.h:128 [inline]
RIP: 0010:rcu_is_watching+0x3a/0xb0 kernel/rcu/tree.c:751
Code: e8 2b 8f 21 09 89 c3 83 f8 08 73 65 49 bf 00 00 00 00 00 fc ff df 4c 8d 34 dd d0 5d 07 8d 4c 89 f0 48 c1 e8 03 42 80 3c 38 00 <74> 08 4c 89 f7 e8 1c 73 7b 00 48 c7 c3 d8 d4 c6 91 49 03 1e 48 89
RSP: 0018:ffffc9000df27758 EFLAGS: 00000246
RAX: 1ffffffff1a0ebba RBX: 0000000000000000 RCX: 955d6bc2b723d400
RDX: 0000000000000002 RSI: ffffffff8b3f5440 RDI: ffffffff8b3f5400
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: fffffbfff31ea3a5 R12: dffffc0000000000
R13: 00000000000002b0 R14: ffffffff8d075dd0 R15: dffffc0000000000
FS: 00007f50964266c0(0000) GS:ffff888126bc6000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00005555627bb608 CR3: 0000000027458000 CR4: 00000000003526f0
Call Trace:
rcu_read_unlock include/linux/rcupdate.h:895 [inline]
blk_cgroup_congested+0x17d/0x210 block/blk-cgroup.c:2250
__folio_throttle_swaprate+0x67/0x190 mm/swapfile.c:4065
folio_throttle_swaprate include/linux/swap.h:617 [inline]
shmem_add_to_page_cache+0x6f1/0xbc0 mm/shmem.c:882
shmem_alloc_and_add_folio mm/shmem.c:1936 [inline]
shmem_get_folio_gfp+0x7d2/0x1a70 mm/shmem.c:2533
shmem_get_folio mm/shmem.c:2639 [inline]
shmem_write_begin+0xef/0x2a0 mm/shmem.c:3289
generic_perform_write+0x29d/0x8c0 mm/filemap.c:4242
shmem_file_write_iter+0xfb/0x120 mm/shmem.c:3464
new_sync_write fs/read_write.c:593 [inline]
vfs_write+0x5d5/0xb40 fs/read_write.c:686
ksys_write+0x14b/0x260 fs/read_write.c:738
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xfa/0xfa0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f50981bda7f
Code: 89 54 24 18 48 89 74 24 10 89 7c 24 08 e8 f9 92 02 00 48 8b 54 24 18 48 8b 74 24 10 41 89 c0 8b 7c 24 08 b8 01 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 31 44 89 c7 48 89 44 24 08 e8 4c 93 02 00 48
RSP: 002b:00007f5096425df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 0000000001000000 RCX: 00007f50981bda7f
RDX: 0000000001000000 RSI: 00007f508e006000 RDI: 0000000000000003
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000005597
R10: 0000000000000002 R11: 0000000000000293 R12: 0000000000000003
R13: 00007f5096425ef0 R14: 00007f5096425eb0 R15: 00007f508e006000