INFO: task syz.0.174:6686 blocked for more than 143 seconds.
Not tainted 6.16.0-rc7-syzkaller-00127-g302f88ff3584 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.174 state:D stack:27320 pid:6686 tgid:6684 ppid:5848 task_flags:0x400140 flags:0x00004004
Call Trace:
context_switch kernel/sched/core.c:5397 [inline]
__schedule+0x116a/0x5dd0 kernel/sched/core.c:6786
__schedule_loop kernel/sched/core.c:6864 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6879
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6936
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6c7/0xb90 kernel/locking/mutex.c:747
expkey_flush+0x20/0x90 fs/nfsd/export.c:252
write_flush.constprop.0+0x2af/0x3d0 net/sunrpc/cache.c:1550
pde_write fs/proc/inode.c:330 [inline]
proc_reg_write+0x23d/0x330 fs/proc/inode.c:342
do_loop_readv_writev fs/read_write.c:850 [inline]
do_loop_readv_writev fs/read_write.c:835 [inline]
vfs_writev+0x5dc/0xde0 fs/read_write.c:1059
do_writev+0x132/0x340 fs/read_write.c:1103
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f3d47f8e9a9
RSP: 002b:00007f3d45df6038 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f3d481b5fa0 RCX: 00007f3d47f8e9a9
RDX: 000000000000000a RSI: 0000200000000200 RDI: 0000000000000004
RBP: 00007f3d48010d69 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f3d481b5fa0 R15: 00007ffcd197b368
Showing all locks held in the system:
1 lock held by pool_workqueue_/3:
#0: ffffffff8e5d0278 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:336
1 lock held by khungtaskd/31:
#0: ffffffff8e5c4c80 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline]
#0: ffffffff8e5c4c80 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline]
#0: ffffffff8e5c4c80 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x36/0x1c0 kernel/locking/lockdep.c:6770
3 locks held by kworker/u8:3/49:
#0: ffff88814c763948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
#1: ffff8880b8524088 (&per_cpu_ptr(group->pcpu, cpu)->seq){-.-.}-{0:0}, at: psi_task_switch+0x2c1/0x8e0 kernel/sched/psi.c:987
#2: ffff88802859c628 (&p->pi_lock){-.-.}-{2:2}, at: class_raw_spinlock_irqsave_constructor include/linux/spinlock.h:557 [inline]
#2: ffff88802859c628 (&p->pi_lock){-.-.}-{2:2}, at: try_to_wake_up+0xb2/0x1680 kernel/sched/core.c:4227
4 locks held by kworker/u8:4/62:
#0: ffff88801c6fe148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
#1: ffffc9000213fd10 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
#2: ffffffff90349f90 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xad/0x890 net/core/net_namespace.c:662
#3: ffffffff8e5d0278 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x1a3/0x3c0 kernel/rcu/tree_exp.h:336
1 lock held by klogd/5207:
#0: ffff8880b843a418 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested kernel/sched/core.c:614 [inline]
#0: ffff8880b843a418 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x7e/0x130 kernel/sched/core.c:599
1 lock held by syz-executor/5855:
#0: ffffffff9035ffe8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:633 [inline]
#0: ffffffff9035ffe8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x230 drivers/net/tun.c:3396
3 locks held by kworker/1:4/5883:
#0: ffff88801b880d48 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x12a2/0x1b70 kernel/workqueue.c:3213
#1: ffffc900041efd10 ((fqdir_free_work).work){+.+.}-{0:0}, at: process_one_work+0x929/0x1b70 kernel/workqueue.c:3214
#2: ffffffff8e5d0140 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6e0 kernel/rcu/tree.c:3786
2 locks held by syz.1.152/6606:
#0: ffffffff90404810 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1218
#1: ffffffff8e9da348 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x687/0xbc0 fs/nfsd/nfsctl.c:1629
3 locks held by syz.0.174/6686:
#0: ffff88807e48b978 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2a2/0x370 fs/file.c:1217
#1: ffff888028e74428 (sb_writers#3){.+.+}-{0:0}, at: do_writev+0x132/0x340 fs/read_write.c:1103
#2: ffffffff8e9da348 (nfsd_mutex){+.+.}-{4:4}, at: expkey_flush+0x20/0x90 fs/nfsd/export.c:252
2 locks held by syz-executor/6946:
#0: ffff88807b2f60e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff88807b2f60e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff88807b2f60e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff88807b2f60e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503
#1: ffffffff8e9da348 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596
2 locks held by getty/7249:
#0: ffff8880322740a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x24/0x80 drivers/tty/tty_ldisc.c:243
#1: ffffc90017aff2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x41b/0x14f0 drivers/tty/n_tty.c:2222
2 locks held by syz.4.378/7535:
#0: ffff88805d94e0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff88805d94e0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff88805d94e0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff88805d94e0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503
#1: ffffffff8e9da348 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596
2 locks held by syz.6.586/8520:
#0: ffff88803244c0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: __super_lock fs/super.c:57 [inline]
#0: ffff88803244c0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:72 [inline]
#0: ffff88803244c0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: deactivate_super fs/super.c:506 [inline]
#0: ffff88803244c0e0 (&type->s_umount_key#50){+.+.}-{4:4}, at: deactivate_super+0xd6/0x100 fs/super.c:503
#1: ffffffff8e9da348 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:596
2 locks held by syz.7.668/8954:
#0: ffffffff90349f90 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:570
#1: ffffffff8e5d0140 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6e0 kernel/rcu/tree.c:3786
2 locks held by syz.7.668/8957:
#0: ffffffff90349f90 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:570
#1: ffffffff8e5d0140 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6e0 kernel/rcu/tree.c:3786
2 locks held by syz.3.670/8974:
#0: ffffffff90349f90 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:570
#1: ffffffff9035ffe8 (rtnl_mutex){+.+.}-{4:4}, at: register_nexthop_notifier+0x1b/0x70 net/ipv4/nexthop.c:3929
2 locks held by syz.8.669/8968:
#0: ffffffff90349f90 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x286/0x5f0 net/core/net_namespace.c:570
#1: ffffffff9035ffe8 (rtnl_mutex){+.+.}-{4:4}, at: ip_tunnel_init_net+0x21d/0x7d0 net/ipv4/ip_tunnel.c:1160
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc7-syzkaller-00127-g302f88ff3584 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
watchdog+0xf70/0x12c0 kernel/hung_task.c:470
kthread+0x3c5/0x780 kernel/kthread.c:464
ret_from_fork+0x5d4/0x6f0 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: 8940 Comm: syz.2.665 Not tainted 6.16.0-rc7-syzkaller-00127-g302f88ff3584 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:trace_irq_enable.constprop.0+0x37/0x120 include/trace/events/preemptirq.h:40
Code: 07 0f 87 f3 00 00 00 89 db be 08 00 00 00 48 89 d8 48 c1 e8 06 48 8d 3c c5 50 5d a9 90 e8 21 94 5c 00 48 0f a3 1d c9 39 e6 0e <0f> 82 92 00 00 00 5b 5d e9 cc 7f c2 09 48 89 fb 65 8b 05 96 0c 0c
RSP: 0018:ffffc9000b7e7a78 EFLAGS: 00000047
RAX: 0000000000000001 RBX: 0000000000000000 RCX: ffffffff81c3237f
RDX: fffffbfff2152bab RSI: 0000000000000008 RDI: ffffffff90a95d50
RBP: 0000000000000286 R08: 0000000000000000 R09: fffffbfff2152baa
R10: ffffffff90a95d57 R11: 0000000000000001 R12: dffffc0000000000
R13: 000000000000003b R14: 0000000000000000 R15: ffffc90013772000
FS: 0000000000000000(0000) GS:ffff88812472d000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000001b315ebff8 CR3: 000000000e382000 CR4: 00000000003526f0
Call Trace:
trace_hardirqs_on+0x26/0x40 kernel/trace/trace_preemptirq.c:73
__raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]
_raw_spin_unlock_irqrestore+0x52/0x80 kernel/locking/spinlock.c:194
__debug_check_no_obj_freed lib/debugobjects.c:1108 [inline]
debug_check_no_obj_freed+0x31f/0x600 lib/debugobjects.c:1129
remove_vm_area+0x1ae/0x3f0 mm/vmalloc.c:3291
vfree+0x90/0xb50 mm/vmalloc.c:3414
kcov_put kernel/kcov.c:439 [inline]
kcov_put kernel/kcov.c:435 [inline]
kcov_close+0x34/0x60 kernel/kcov.c:535
__fput+0x402/0xb70 fs/file_table.c:465
task_work_run+0x14d/0x240 kernel/task_work.c:227
exit_task_work include/linux/task_work.h:40 [inline]
do_exit+0x86c/0x2bd0 kernel/exit.c:964
do_group_exit+0xd3/0x2a0 kernel/exit.c:1105
__do_sys_exit_group kernel/exit.c:1116 [inline]
__se_sys_exit_group kernel/exit.c:1114 [inline]
__x64_sys_exit_group+0x3e/0x50 kernel/exit.c:1114
x64_sys_call+0x1530/0x1730 arch/x86/include/generated/asm/syscalls_64.h:232
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x490 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fb505b8e9a9
Code: Unable to access opcode bytes at 0x7fb505b8e97f.
RSP: 002b:00007ffed5264848 EFLAGS: 00000246 ORIG_RAX: 00000000000000e7
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007fb505b8e9a9
RDX: 0000000000000064 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00007ffed52648ac R08: 00000014d526493f R09: 00000000000927c0
R10: 000000000005a2b4 R11: 0000000000000246 R12: 00000000000000ce
R13: 00000000000927c0 R14: 000000000004c938 R15: 00007ffed5264900