INFO: task syz.9.1353:18718 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.1353 state:D stack:25624 pid:18718 tgid:18717 ppid:8515 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x145f/0x5070 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
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+0x10e/0x160 kernel/kthread.c:1559
__alloc_workqueue+0x1485/0x1b80 kernel/workqueue.c:5797
alloc_workqueue_noprof+0xd4/0x210 kernel/workqueue.c:5820
btrfs_init_workqueues+0x25e/0x680 fs/btrfs/disk-io.c:1978
open_ctree+0x141d/0x3d20 fs/btrfs/disk-io.c:3411
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+0x302/0xa10 fs/namespace.c:3712
do_mount fs/namespace.c:4035 [inline]
__do_sys_mount fs/namespace.c:4224 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4201
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fc4276c0eea
RSP: 002b:00007fc42591de68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fc42591def0 RCX: 00007fc4276c0eea
RDX: 00002000000055c0 RSI: 0000200000000000 RDI: 00007fc42591deb0
RBP: 00002000000055c0 R08: 00007fc42591def0 R09: 000000000300000a
R10: 000000000300000a R11: 0000000000000246 R12: 0000200000000000
R13: 00007fc42591deb0 R14: 00000000000055a3 R15: 0000200000000080
INFO: task syz.3.1356:18723 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.1356 state:D stack:25624 pid:18723 tgid:18722 ppid:11354 task_flags:0x400140 flags:0x00080003
Call Trace:
context_switch kernel/sched/core.c:5256 [inline]
__schedule+0x145f/0x5070 kernel/sched/core.c:6863
__schedule_loop kernel/sched/core.c:6945 [inline]
schedule+0x165/0x360 kernel/sched/core.c:6960
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+0x10e/0x160 kernel/kthread.c:1559
__alloc_workqueue+0x1485/0x1b80 kernel/workqueue.c:5797
alloc_workqueue_noprof+0xd4/0x210 kernel/workqueue.c:5820
btrfs_alloc_ordered_workqueue+0x1c3/0x290 fs/btrfs/async-thread.c:140
btrfs_init_workqueues+0x396/0x680 fs/btrfs/disk-io.c:1989
open_ctree+0x141d/0x3d20 fs/btrfs/disk-io.c:3411
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+0x302/0xa10 fs/namespace.c:3712
do_mount fs/namespace.c:4035 [inline]
__do_sys_mount fs/namespace.c:4224 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4201
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xec/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f6ef4240eea
RSP: 002b:00007f6ef24a5e68 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f6ef24a5ef0 RCX: 00007f6ef4240eea
RDX: 00002000000055c0 RSI: 0000200000000000 RDI: 00007f6ef24a5eb0
RBP: 00002000000055c0 R08: 00007f6ef24a5ef0 R09: 000000000300000a
R10: 000000000300000a R11: 0000000000000246 R12: 0000200000000000
R13: 00007f6ef24a5eb0 R14: 00000000000055a3 R15: 0000200000000080
Showing all locks held in the system:
1 lock held by khungtaskd/38:
#0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline]
#0: ffffffff8d5ae940 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
2 locks held by getty/5556:
#0: ffff888034a8a0a0 (&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+0x44f/0x1460 drivers/tty/n_tty.c:2211
2 locks held by kworker/u8:21/8217:
#0: ffff888141ab6938 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff888141ab6938 ((wq_completion)iou_exit){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340
#1: ffffc90004047bc0 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc90004047bc0 ((work_completion)(&ctx->exit_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340
3 locks held by kworker/u8:22/8314:
3 locks held by kworker/u8:25/9832:
#0: ffff88814d562138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline]
#0: ffff88814d562138 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340
#1: ffffc9000d687bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline]
#1: ffffc9000d687bc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340
#2: ffffffff8e8a5978 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#2: ffffffff8e8a5978 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x119/0x15a0 net/ipv6/addrconf.c:4194
1 lock held by syz.9.1353/18718:
#0: ffff88802763e0d0 (&type->s_umount_key#51/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:344
1 lock held by syz.3.1356/18723:
#0: ffff8880267040d0 (&type->s_umount_key#51/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:344
4 locks held by kworker/u8:29/19242:
1 lock held by syz.4.1470/20438:
#0: ffff88802389e0d0 (&type->s_umount_key#51/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xab0 fs/super.c:344
1 lock held by syz-executor/20678:
#0: ffffffff8e8a5978 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#0: ffffffff8e8a5978 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978
4 locks held by syz.5.1503/20966:
#0: ffff88803114cbc8 (vm_lock){++++}-{0:0}, at: lock_vma_under_rcu+0x1a7/0x4a0 mm/mmap_lock.c:259
#1: ffff88814e4f65f8 (sb_pagefaults){++++}-{0:0}, at: percpu_down_read_freezable include/linux/percpu-rwsem.h:83 [inline]
#1: ffff88814e4f65f8 (sb_pagefaults){++++}-{0:0}, at: __sb_start_write include/linux/fs/super.h:19 [inline]
#1: ffff88814e4f65f8 (sb_pagefaults){++++}-{0:0}, at: sb_start_pagefault include/linux/fs/super.h:159 [inline]
#1: ffff88814e4f65f8 (sb_pagefaults){++++}-{0:0}, at: ext4_page_mkwrite+0x1f7/0x1190 fs/ext4/inode.c:6667
#2: ffffffff8d6d4870 (remove_cache_srcu){.+.+}-{0:0}, at: srcu_lock_acquire include/linux/srcu.h:185 [inline]
#2: ffffffff8d6d4870 (remove_cache_srcu){.+.+}-{0:0}, at: srcu_read_lock+0x27/0x60 include/linux/srcu.h:277
#3: ffff888019efc158 (&n->list_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline]
#3: ffff888019efc158 (&n->list_lock){+.+.}-{3:3}, at: __put_partials+0x55/0x170 mm/slub.c:3866
8 locks held by syz.5.1503/20968:
10 locks held by syz.8.1504/20977:
8 locks held by syz.8.1504/21034:
3 locks held by syz.2.1507/21029:
2 locks held by udevadm/21032:
4 locks held by dhcpcd-run-hook/21035:
#0: ffffffff8d66d590 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1528 [inline]
#0: ffffffff8d66d590 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0x131/0x4b0 kernel/fork.c:1581
#1: ffff888035a85030 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:353 [inline]
#1: ffff888035a85030 (&mm->mmap_lock){++++}-{4:4}, at: dup_mmap+0x125/0x1b40 mm/mmap.c:1726
#2: ffff888038d41070 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:343 [inline]
#2: ffff888038d41070 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x20d/0x1b40 mm/mmap.c:1733
#3: ffff888019efc158 (&n->list_lock){+.+.}-{3:3}, at: spin_lock include/linux/spinlock_rt.h:44 [inline]
#3: ffff888019efc158 (&n->list_lock){+.+.}-{3:3}, at: get_partial_node+0x44/0x3e0 mm/slub.c:3514
1 lock held by syz.1.1508/21038:
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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:160 [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+0xf95/0xfe0 kernel/hung_task.c:515
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 29 Comm: ktimers/1 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
RIP: 0010:rcu_is_watching+0x70/0xb0 kernel/rcu/tree.c:753
Code: c3 58 4c b4 91 49 03 1e 48 89 d8 48 c1 e8 03 42 0f b6 04 38 84 c0 75 34 8b 03 65 ff 0d d9 6f 0d 10 74 11 83 e0 04 c1 e8 02 5b <41> 5e 41 5f c3 cc cc cc cc cc e8 41 77 8d ff eb e8 48 c7 c7 40 47
RSP: 0018:ffffc90000a3f9a8 EFLAGS: 00000202
RAX: 0000000000000001 RBX: 0000000080000000 RCX: 0000000080000001
RDX: 0000000000000100 RSI: ffffffff8b3f57c0 RDI: ffffffff8b3f5780
RBP: ffffc90000a3fab0 R08: 0000000000000000 R09: 0000000000000100
R10: dffffc0000000000 R11: fffffbfff1db66cf R12: 0000000000000001
R13: ffff88802438f610 R14: ffffffff8d017dd8 R15: dffffc0000000000
FS: 0000000000000000(0000) GS:ffff888126def000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b319dfff8 CR3: 0000000035582000 CR4: 00000000003526f0
Call Trace:
trace_timer_expire_entry include/trace/events/timer.h:92 [inline]
call_timer_fn+0x14c/0x590 kernel/time/timer.c:1747
expire_timers kernel/time/timer.c:1799 [inline]
__run_timers kernel/time/timer.c:2373 [inline]
__run_timer_base+0x648/0x970 kernel/time/timer.c:2385
run_timer_base kernel/time/timer.c:2394 [inline]
run_timer_softirq+0xb7/0x180 kernel/time/timer.c:2404
handle_softirqs+0x1df/0x650 kernel/softirq.c:622
__do_softirq kernel/softirq.c:656 [inline]
run_ktimerd+0x69/0x100 kernel/softirq.c:1138
smpboot_thread_fn+0x542/0xa60 kernel/smpboot.c:160
kthread+0x711/0x8a0 kernel/kthread.c:463
ret_from_fork+0x510/0xa50 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246