INFO: task syz.0.1350:20802 blocked for more than 143 seconds.
Tainted: G I L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.1350 state:D stack:27016 pid:20802 tgid:20796 ppid:9546 task_flags:0x400140 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0xfee/0x60e0 kernel/sched/core.c:6907
__schedule_loop kernel/sched/core.c:6989 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7004
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7061
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
expkey_flush+0x18/0x90 fs/nfsd/export.c:250
write_flush.isra.0+0x2af/0x3d0 net/sunrpc/cache.c:1551
pde_write fs/proc/inode.c:330 [inline]
proc_reg_write+0x240/0x330 fs/proc/inode.c:342
do_loop_readv_writev fs/read_write.c:852 [inline]
do_loop_readv_writev fs/read_write.c:837 [inline]
vfs_writev+0x5ea/0xe10 fs/read_write.c:1061
do_writev+0x13e/0x340 fs/read_write.c:1105
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9b1f19c799
RSP: 002b:00007f9b2008f028 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f9b1f415fa0 RCX: 00007f9b1f19c799
RDX: 000000000000000a RSI: 0000200000000240 RDI: 0000000000000003
RBP: 00007f9b1f232bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9b1f416038 R14: 00007f9b1f415fa0 R15: 00007ffc392cd518
INFO: task syz.0.1350:20820 blocked for more than 145 seconds.
Tainted: G I L syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.1350 state:D stack:29000 pid:20820 tgid:20796 ppid:9546 task_flags:0x400040 flags:0x00080002
Call Trace:
context_switch kernel/sched/core.c:5295 [inline]
__schedule+0xfee/0x60e0 kernel/sched/core.c:6907
__schedule_loop kernel/sched/core.c:6989 [inline]
schedule+0xdd/0x390 kernel/sched/core.c:7004
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7061
__mutex_lock_common kernel/locking/mutex.c:692 [inline]
__mutex_lock+0xc9a/0x1b90 kernel/locking/mutex.c:776
fdget_pos+0x2aa/0x380 fs/file.c:1261
class_fd_pos_constructor include/linux/file.h:85 [inline]
do_writev+0x77/0x340 fs/read_write.c:1096
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0x106/0xf80 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f9b1f19c799
RSP: 002b:00007f9b2004d028 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 00007f9b1f416180 RCX: 00007f9b1f19c799
RDX: 000000000000000a RSI: 0000200000000240 RDI: 0000000000000003
RBP: 00007f9b1f232bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f9b1f416218 R14: 00007f9b1f416180 R15: 00007ffc392cd518
Showing all locks held in the system:
3 locks held by kworker/0:1/10:
#0: ffff88813fe63548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1287/0x1920 kernel/workqueue.c:3250
#1: ffffc900000f7d08 ((fqdir_free_work).work){+.+.}-{0:0}, at: process_one_work+0x93c/0x1920 kernel/workqueue.c:3251
#2: ffffffff8e7f4d00 (rcu_state.barrier_mutex){+.+.}-{4:4}, at: rcu_barrier+0x48/0x6d0 kernel/rcu/tree.c:3828
1 lock held by khungtaskd/31:
#0: ffffffff8e7e9220 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline]
#0: ffffffff8e7e9220 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline]
#0: ffffffff8e7e9220 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x3d/0x184 kernel/locking/lockdep.c:6775
3 locks held by kworker/0:2/980:
#0: ffff8880b843b2e0 (&rq->__lock){-.-.}-{2:2}, at: raw_spin_rq_lock_nested+0x2c/0x140 kernel/sched/core.c:647
#1: ffff88805538c008 (&____s->seqcount#17){.-.-}-{0:0}, at: trace_find_filtered_pid kernel/trace/trace_pid.c:15 [inline]
#1: ffff88805538c008 (&____s->seqcount#17){.-.-}-{0:0}, at: trace_ignore_this_task+0xbc/0x100 kernel/trace/trace_pid.c:44
#2: ffff888037561020 (&r->consumer_lock#2){+.+.}-{3:3}, at: spin_lock_bh include/linux/spinlock.h:347 [inline]
#2: ffff888037561020 (&r->consumer_lock#2){+.+.}-{3:3}, at: ptr_ring_consume_bh include/linux/ptr_ring.h:375 [inline]
#2: ffff888037561020 (&r->consumer_lock#2){+.+.}-{3:3}, at: wg_packet_decrypt_worker+0x2b2/0x540 drivers/net/wireguard/receive.c:499
2 locks held by syz-executor/5822:
#0: ffff88807a5240e0 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88807a5240e0 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88807a5240e0 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88807a5240e0 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec586e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
2 locks held by kworker/0:3/5869:
#0: ffff88813fe63548 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x1287/0x1920 kernel/workqueue.c:3250
#1: ffffc9000416fd08 (free_ipc_work){+.+.}-{0:0}, at: process_one_work+0x93c/0x1920 kernel/workqueue.c:3251
3 locks held by kworker/u11:1/12252:
2 locks held by syz.2.1242/19561:
#0: ffffffff906be670 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8ec586e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x718/0xc60 fs/nfsd/nfsctl.c:1597
2 locks held by syz-executor/20134:
#0: ffff88803566e0e0 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88803566e0e0 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88803566e0e0 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88803566e0e0 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec586e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
3 locks held by syz.0.1350/20802:
#0: ffff88802ae98478 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1261
#1: ffff88802e428420 (sb_writers#3){.+.+}-{0:0}, at: do_writev+0x13e/0x340 fs/read_write.c:1105
#2: ffffffff8ec586e8 (nfsd_mutex){+.+.}-{4:4}, at: expkey_flush+0x18/0x90 fs/nfsd/export.c:250
1 lock held by syz.0.1350/20820:
#0: ffff88802ae98478 (&f->f_pos_lock){+.+.}-{4:4}, at: fdget_pos+0x2aa/0x380 fs/file.c:1261
2 locks held by syz-executor/21306:
#0: ffff88802d5620e0 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline]
#0: ffff88802d5620e0 (&type->s_umount_key#53){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline]
#0: ffff88802d5620e0 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super fs/super.c:508 [inline]
#0: ffff88802d5620e0 (&type->s_umount_key#53){++++}-{4:4}, at: deactivate_super+0xdf/0x110 fs/super.c:505
#1: ffffffff8ec586e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_shutdown_threads+0x5b/0xf0 fs/nfsd/nfssvc.c:575
3 locks held by kworker/u11:31/24773:
#0: ffff888033762948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x1287/0x1920 kernel/workqueue.c:3250
#1: ffffc9000338fd08 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work+0x93c/0x1920 kernel/workqueue.c:3251
#2: ffffffff906124e8 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline]
#2: ffffffff906124e8 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x11f/0x1360 net/ipv6/addrconf.c:4198
3 locks held by kworker/0:5/25556:
2 locks held by syz.6.1729/25674:
#0: ffffffff906be670 (cb_lock){++++}-{4:4}, at: genl_rcv+0x19/0x40 net/netlink/genetlink.c:1217
#1: ffffffff8ec586e8 (nfsd_mutex){+.+.}-{4:4}, at: nfsd_nl_threads_set_doit+0x718/0xc60 fs/nfsd/nfsctl.c:1597
3 locks held by syz-executor/26049:
#0: ffff8880567a0ec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:500
#1: ffff8880567a00c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x35c/0x1240 net/bluetooth/hci_sync.c:5346
#2: ffffffff908aa4e8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2151 [inline]
#2: ffffffff908aa4e8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x280 net/bluetooth/hci_conn.c:2644
1 lock held by syz.3.1770/26272:
4 locks held by syz-executor/26453:
#0: ffff88807aeacec0 (&hdev->req_lock){+.+.}-{4:4}, at: hci_dev_do_close+0x26/0xb0 net/bluetooth/hci_core.c:500
#1: ffff88807aeac0c0 (&hdev->lock){+.+.}-{4:4}, at: hci_dev_close_sync+0x35c/0x1240 net/bluetooth/hci_sync.c:5346
#2: ffffffff908aa4e8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_disconn_cfm include/net/bluetooth/hci_core.h:2151 [inline]
#2: ffffffff908aa4e8 (hci_cb_list_lock){+.+.}-{4:4}, at: hci_conn_hash_flush+0xbb/0x280 net/bluetooth/hci_conn.c:2644
#3: ffff8880983d5af8 (&conn->lock#2){+.+.}-{4:4}, at: l2cap_conn_del+0x80/0x770 net/bluetooth/l2cap_core.c:1755
2 locks held by syz.7.1785/26749:
#0: ffffffff906124e8 (rtnl_mutex){+.+.}-{4:4}, at: tun_detach drivers/net/tun.c:634 [inline]
#0: ffffffff906124e8 (rtnl_mutex){+.+.}-{4:4}, at: tun_chr_close+0x38/0x220 drivers/net/tun.c:3436
#1: ffffffff8e7f4e38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
2 locks held by syz.3.1787/26853:
#0: ffffffff905f9b90 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x451/0x7c0 net/core/net_namespace.c:577
#1: ffffffff906124e8 (rtnl_mutex){+.+.}-{4:4}, at: ipmr_net_exit_batch+0x15/0xa0 net/ipv4/ipmr.c:3276
2 locks held by dhcpcd/27001:
#0: ffff888079572260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1709 [inline]
#0: ffff888079572260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf50 net/packet/af_packet.c:3197
#1: ffffffff8e7f4e38 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock+0x19e/0x3c0 kernel/rcu/tree_exp.h:343
1 lock held by dhcpcd/27002:
#0: ffff888056780260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1709 [inline]
#0: ffff888056780260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf50 net/packet/af_packet.c:3197
1 lock held by dhcpcd/27003:
#0: ffff88804556c260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1709 [inline]
#0: ffff88804556c260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf50 net/packet/af_packet.c:3197
1 lock held by dhcpcd/27005:
#0: ffff888026e36260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1709 [inline]
#0: ffff888026e36260 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x2c/0xf50 net/packet/af_packet.c:3197
=============================================
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Tainted: G I L syzkaller #0 PREEMPT(full)
Tainted: [I]=FIRMWARE_WORKAROUND, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
Call Trace:
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x100/0x190 lib/dump_stack.c:120
nmi_cpu_backtrace.cold+0x12d/0x151 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x1d7/0x230 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+0x141/0x190 lib/sys_info.c:165
check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline]
watchdog+0xd25/0x1050 kernel/hung_task.c:515
kthread+0x370/0x450 kernel/kthread.c:467
ret_from_fork+0x754/0xd80 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245