INFO: task syz.6.1201:20557 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.6.1201 state:D stack:25400 pid:20557 tgid:20555 ppid:14537 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5260 [inline]
__schedule+0x1472/0x4fe0 kernel/sched/core.c:6867
__schedule_loop kernel/sched/core.c:6949 [inline]
schedule+0x164/0x360 kernel/sched/core.c:6964
schedule_timeout+0xc3/0x2c0 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+0x2cc/0x5e0 kernel/sched/completion.c:153
kthread_flush_worker+0x138/0x1a0 kernel/kthread.c:1559
__alloc_workqueue+0xfed/0x1e90 kernel/workqueue.c:5797
alloc_workqueue_noprof+0xe3/0x210 kernel/workqueue.c:5820
btrfs_alloc_workqueue+0x1ec/0x2d0 fs/btrfs/async-thread.c:112
btrfs_init_workqueues+0x348/0x680 fs/btrfs/disk-io.c:1964
open_ctree+0x1580/0x3f00 fs/btrfs/disk-io.c:3402
btrfs_fill_super fs/btrfs/super.c:981 [inline]
btrfs_get_tree_super fs/btrfs/super.c:1944 [inline]
btrfs_get_tree_subvol fs/btrfs/super.c:2087 [inline]
btrfs_get_tree+0x1061/0x1920 fs/btrfs/super.c:2121
vfs_get_tree+0x92/0x2a0 fs/super.c:1751
fc_mount fs/namespace.c:1199 [inline]
do_new_mount_fc fs/namespace.c:3636 [inline]
do_new_mount+0x329/0xa50 fs/namespace.c:3712
do_mount fs/namespace.c:4035 [inline]
__do_sys_mount fs/namespace.c:4224 [inline]
__se_sys_mount+0x31d/0x420 fs/namespace.c:4201
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xe2/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f72bc2cc14a
RSP: 002b:00007f72ba525e58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f72ba525ee0 RCX: 00007f72bc2cc14a
RDX: 00002000000055c0 RSI: 0000200000000000 RDI: 00007f72ba525ea0
RBP: 00002000000055c0 R08: 00007f72ba525ee0 R09: 000000000300000a
R10: 000000000300000a R11: 0000000000000246 R12: 0000200000000000
R13: 00007f72ba525ea0 R14: 00000000000055a3 R15: 0000200000000080
Showing all locks held in the system:
2 locks held by ksoftirqd/0/15:
1 lock held by khungtaskd/38:
#0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8dbc77c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
4 locks held by kworker/u8:6/1306:
2 locks held by kworker/u8:11/3648:
#0: ffff88813fe69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88813fe69938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9d4/0x17a0 kernel/workqueue.c:3340
#1: ffffc9000dfe7bc0 ((reaper_work).work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc9000dfe7bc0 ((reaper_work).work){+.+.}-{0:0}, at: process_scheduled_works+0xa0f/0x17a0 kernel/workqueue.c:3340
7 locks held by kworker/u8:14/3742:
2 locks held by getty/5562:
#0: ffff8880346f40a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
3 locks held by udevd/14707:
1 lock held by udevd/14708:
#0: ffff888022196ea8 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1042 [inline]
#0: ffff888022196ea8 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: blkdev_read_iter+0x2ff/0x440 block/fops.c:855
1 lock held by syz.6.1201/20557:
#0: ffff88802912e0d0 (&type->s_umount_key#72/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:344
5 locks held by syz.8.1370/23397:
1 lock held by syz.1.1369/23347:
#0: ffff88803834e0d0 (&type->s_umount_key#52/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:344
5 locks held by syz.2.1372/23376:
1 lock held by syz.3.1373/23379:
#0: ffff88805c5f60d0 (&type->s_umount_key#52/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:344
2 locks held by syz.5.1371/23392:
=============================================
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 01/24/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:161 [inline]
__sys_info lib/sys_info.c:157 [inline]
sys_info+0x135/0x170 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xf90/0xfe0 kernel/hung_task.c:515
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 1306 Comm: kworker/u8:6 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
Workqueue: bat_events batadv_dat_purge
RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:37 [inline]
RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:114 [inline]
RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:128 [inline]
RIP: 0010:__local_bh_enable_ip+0x9b/0x2b0 kernel/softirq.c:270
Code: 10 85 c0 75 0f 65 8b 05 5b e7 9e 10 85 c0 0f 84 65 01 00 00 48 8d 35 00 00 00 00 48 c7 c7 00 f0 a5 8d e8 88 45 18 00 9c 41 5c 41 f7 c4 00 02 00 00 74 05 e8 c6 46 44 00 65 4c 8b 35 f6 a4 9e
RSP: 0018:ffffc90004fcf9d0 EFLAGS: 00000282
RAX: 05b094625b1a2600 RBX: 0000000000000200 RCX: 0000000000000046
RDX: 00000000169860c9 RSI: ffffffff8d592640 RDI: ffffffff8b85e900
RBP: 0000000000000400 R08: ffffffff8186c66c R09: ffffffff8dbc77c0
R10: 0000000000000000 R11: fffffbfff1e8fbef R12: 0000000000000282
R13: dffffc0000000000 R14: ffff8880374196c0 R15: 0000000000000001
FS: 0000000000000000(0000) GS:ffff8881265c9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0fc34a3000 CR3: 00000000523a8000 CR4: 00000000003526f0
Call Trace:
local_bh_enable include/linux/bottom_half.h:33 [inline]
spin_unlock_bh include/linux/spinlock_rt.h:111 [inline]
__batadv_dat_purge+0x344/0x400 net/batman-adv/distributed-arp-table.c:185
batadv_dat_purge+0x20/0x70 net/batman-adv/distributed-arp-table.c:204
process_one_work kernel/workqueue.c:3257 [inline]
process_scheduled_works+0xaec/0x17a0 kernel/workqueue.c:3340
worker_thread+0xda6/0x1360 kernel/workqueue.c:3421
kthread+0x726/0x8b0 kernel/kthread.c:463
ret_from_fork+0x51b/0xa40 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246