INFO: task syz.5.573:9115 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.5.573 state:D stack:23800 pid:9115 tgid:9107 ppid:6993 task_flags:0x400140 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5360 [inline]
__schedule+0x1798/0x4cc0 kernel/sched/core.c:6964
__schedule_loop kernel/sched/core.c:7046 [inline]
schedule+0x165/0x360 kernel/sched/core.c:7061
wb_wait_for_completion+0x15f/0x260 fs/fs-writeback.c:216
sync_inodes_sb+0x1bb/0xa10 fs/fs-writeback.c:2834
sync_filesystem+0x17a/0x230 fs/sync.c:64
nilfs_reconfigure+0xae/0x430 fs/nilfs2/super.c:1136
reconfigure_super+0x227/0x890 fs/super.c:1076
do_remount fs/namespace.c:3354 [inline]
path_mount+0xd1a/0xfe0 fs/namespace.c:4104
do_mount fs/namespace.c:4125 [inline]
__do_sys_mount fs/namespace.c:4324 [inline]
__se_sys_mount+0x313/0x410 fs/namespace.c:4301
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: 0033:0x7fd170d8eba9
RSP: 002b:00007fd171bd0038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007fd170fd6090 RCX: 00007fd170d8eba9
RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000000000000000
RBP: 00007fd170e11e19 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000c22 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd170fd6128 R14: 00007fd170fd6090 R15: 00007ffe1d711258
Showing all locks held in the system:
1 lock held by khungtaskd/31:
#0: ffffffff8e33c820 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e33c820 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e33c820 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775
1 lock held by udevd/5235:
2 locks held by getty/5629:
#0: ffff8880300e90a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1:
ffffc9000332b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x43e/0x1400 drivers/tty/n_tty.c:2222
6 locks held by kworker/0:3/5858:
3 locks held by kworker/1:3/5928:
#0: ffff888141696148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff888141696148 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc9000442fba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc9000442fba0 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
#2: ffff8880281a5198 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
#2: ffff8880281a5198 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4a20 drivers/usb/core/hub.c:5898
2 locks held by kworker/u8:23/8897:
#0: ffff8880212c6148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3238 [inline]
#0: ffff8880212c6148 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3346
#1: ffffc9000af27ba0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3239 [inline]
#1: ffffc9000af27ba0 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3346
2 locks held by syz.5.573/9115:
#0: ffff88807b9840e0 (&type->s_umount_key#65){++++}-{4:4}, at: do_remount fs/namespace.c:3351 [inline]
#0: ffff88807b9840e0 (&type->s_umount_key#65){++++}-{4:4}, at: path_mount+0xcd4/0xfe0 fs/namespace.c:4104
#1: ffff888024ffe7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:387 [inline]
#1: ffff888024ffe7d0 (&bdi->wb_switch_rwsem){+.+.}-{4:4}, at: sync_inodes_sb+0x19f/0xa10 fs/fs-writeback.c:2832
1 lock held by segctord/9111:
#0: ffff8880b8639f98 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0xad/0x140 kernel/sched/core.c:644
5 locks held by kworker/u8:26/10030:
4 locks held by kworker/u8:31/10035:
1 lock held by syz.2.977/11095:
#0: ffff888076c5ace0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:330 [inline]
#0: ffff888076c5ace0 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x211/0x4d0 mm/util.c:578
1 lock held by syz.2.977/11103:
#0: ffff888076c5ace0 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock_killable+0x1d/0x70 include/linux/mmap_lock.h:377
4 locks held by syz.2.977/11104:
2 locks held by syz.6.976/11105:
#0: ffff8880775ce3c8 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:980 [inline]
#0: ffff8880775ce3c8 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: __sock_release net/socket.c:648 [inline]
#0: ffff8880775ce3c8 (&sb->s_type->i_mutex_key#11){+.+.}-{4:4}, at: sock_close+0x9b/0x240 net/socket.c:1442
#1: ffffffff8e3422b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:343 [inline]
#1: ffffffff8e3422b8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x3b9/0x730 kernel/rcu/tree_exp.h:957
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
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: 6853 Comm: udevd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/18/2025
RIP: 0010:__rq_lockp kernel/sched/sched.h:1374 [inline]
RIP: 0010:lockdep_assert_rq_held kernel/sched/sched.h:1512 [inline]
RIP: 0010:rq_clock kernel/sched/sched.h:1660 [inline]
RIP: 0010:start_dl_timer+0x226/0x4f0 kernel/sched/deadline.c:1106
Code: 03 42 0f b6 04 30 84 c0 0f 85 fb 01 00 00 48 89 6c 24 10 83 3d 3a f3 2a 0e 00 74 5b 49 8d af 70 0e 00 00 48 89 e8 48 c1 e8 03 <42> 0f b6 04 30 84 c0 0f 85 33 02 00 00 83 7d 00 00 4c 89 ff 74 21
RSP: 0018:ffffc9001c72f3f0 EFLAGS: 00000806
RAX: 1ffff110170c75be RBX: ffff8880b863a970 RCX: ffff88807e5f5ac0
RDX: 0000000000000000 RSI: 0000000000000018 RDI: 0000000000000040
RBP: ffff8880b863adf0 R08: 0000000000000000 R09: ffffffff81adfa7e
R10: 000000000000000b R11: ffffffff81687e40 R12: 000000711be72bbd
R13: 000000738a4ab006 R14: dffffc0000000000 R15: ffff8880b8639f80
FS: 00007f621bbc9880(0000) GS:ffff8881259e8000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b34263fff CR3: 000000006744e000 CR4: 00000000003526f0
Call Trace:
update_curr_dl_se+0x502/0x990 kernel/sched/deadline.c:1498
update_curr+0x3fb/0x730 kernel/sched/fair.c:1243
pick_task_fair+0xd6/0x5c0 kernel/sched/fair.c:8825
pick_task kernel/sched/core.c:6064 [inline]
pick_next_task kernel/sched/core.c:6164 [inline]
__schedule+0x2de8/0x4cc0 kernel/sched/core.c:6905
preempt_schedule_irq+0xb5/0x150 kernel/sched/core.c:7291
irqentry_exit+0x6f/0x90 kernel/entry/common.c:211
asm_sysvec_reschedule_ipi+0x1a/0x20 arch/x86/include/asm/idtentry.h:702
RIP: 0010:lock_acquire+0x175/0x360 kernel/locking/lockdep.c:5872
Code: 00 00 00 00 9c 8f 44 24 30 f7 44 24 30 00 02 00 00 0f 85 cd 00 00 00 f7 44 24 08 00 02 00 00 74 01 fb 65 48 8b 05 0b 23 26 11 <48> 3b 44 24 58 0f 85 f2 00 00 00 48 83 c4 60 5b 41 5c 41 5d 41 5e
RSP: 0018:ffffc9001c72f958 EFLAGS: 00000206
RAX: 8e8dcdb3418e0200 RBX: 0000000000000000 RCX: 8e8dcdb3418e0200
RDX: 0000000000000000 RSI: ffffffff8ddae1af RDI: ffffffff8c036f00
RBP: ffffffff825f194f R08: 0000000000000000 R09: ffffffff825f194f
R10: ffff88801befcc60 R11: ffffffff825f18d0 R12: 0000000000000001
R13: ffff88801b6ffa20 R14: 0000000000000001 R15: 0000000000000246
down_read+0x46/0x2e0 kernel/locking/rwsem.c:1537
kernfs_iop_permission+0x7f/0x430 fs/kernfs/inode.c:289
do_inode_permission fs/namei.c:526 [inline]
inode_permission+0x285/0x470 fs/namei.c:593
may_lookup fs/namei.c:1844 [inline]
link_path_walk+0x232/0xea0 fs/namei.c:2453
path_lookupat+0x97/0x430 fs/namei.c:2661
filename_lookup+0x212/0x570 fs/namei.c:2691
do_readlinkat+0xd9/0x500 fs/stat.c:576
__do_sys_readlink fs/stat.c:613 [inline]
__se_sys_readlink fs/stat.c:610 [inline]
__x64_sys_readlink+0x7f/0x90 fs/stat.c:610
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: 0033:0x7f621b5153a7
Code: 00 00 90 48 83 ec 10 48 63 ff 45 31 c9 45 31 c0 6a 00 31 c9 e8 8a 20 f9 ff 48 83 c4 18 c3 0f 1f 44 00 00 b8 59 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 01 c3 48 8b 15 21 ba 0d 00 f7 d8 64 89 02 48
RSP: 002b:00007ffc1b08e998 EFLAGS: 00000246 ORIG_RAX: 0000000000000059
RAX: ffffffffffffffda RBX: 00007ffc1b08ee70 RCX: 00007f621b5153a7
RDX: 0000000000000400 RSI: 00007ffc1b08e9a0 RDI: 00007ffc1b08ee70
RBP: 00007ffc1b08e9a0 R08: 0000559ffb549920 R09: 0000000000000020
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000400
R13: 00007ffc1b08f6a5 R14: 0000559fc9953ca4 R15: 0000559fc9953bcc