INFO: task dhcpcd:4654 blocked for more than 143 seconds. Not tainted 6.3.0-rc7-syzkaller-00089-gcb0856346a60 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:dhcpcd state:D stack:22896 pid:4654 ppid:4653 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:5307 [inline] __schedule+0xc91/0x5770 kernel/sched/core.c:6625 schedule+0xde/0x1a0 kernel/sched/core.c:6701 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6760 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0xa3b/0x1350 kernel/locking/mutex.c:747 netlink_dump+0xbe/0xc50 net/netlink/af_netlink.c:2246 netlink_recvmsg+0xc09/0xe60 net/netlink/af_netlink.c:2024 sock_recvmsg_nosec net/socket.c:1017 [inline] sock_recvmsg+0xe2/0x160 net/socket.c:1038 ____sys_recvmsg+0x210/0x5a0 net/socket.c:2720 ___sys_recvmsg+0xf2/0x180 net/socket.c:2762 __sys_recvmsg+0xf4/0x1c0 net/socket.c:2792 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f41aa348003 RSP: 002b:00007fff1a9be028 EFLAGS: 00000246 ORIG_RAX: 000000000000002f RAX: ffffffffffffffda RBX: 00007fff1a9bf160 RCX: 00007f41aa348003 RDX: 0000000000000000 RSI: 00007fff1a9bf080 RDI: 0000000000000018 RBP: 00007fff1a9bf0f0 R08: 00007fff1a9bf064 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000246 R12: 00007fff1a9bf080 R13: 00007fff1a9bf064 R14: 00007fff1a9bf070 R15: 00007fff1a9be030 INFO: task kworker/0:3:5118 blocked for more than 143 seconds. Not tainted 6.3.0-rc7-syzkaller-00089-gcb0856346a60 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/0:3 state:D stack:22752 pid:5118 ppid:2 flags:0x00004000 Workqueue: events linkwatch_event Call Trace: context_switch kernel/sched/core.c:5307 [inline] __schedule+0xc91/0x5770 kernel/sched/core.c:6625 schedule+0xde/0x1a0 kernel/sched/core.c:6701 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6760 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0xa3b/0x1350 kernel/locking/mutex.c:747 linkwatch_event+0xf/0x70 net/core/link_watch.c:277 process_one_work+0x991/0x15c0 kernel/workqueue.c:2390 worker_thread+0x669/0x1090 kernel/workqueue.c:2537 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 INFO: task kworker/1:4:14028 blocked for more than 143 seconds. Not tainted 6.3.0-rc7-syzkaller-00089-gcb0856346a60 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:4 state:D stack:25112 pid:14028 ppid:2 flags:0x00004000 Workqueue: events switchdev_deferred_process_work Call Trace: context_switch kernel/sched/core.c:5307 [inline] __schedule+0xc91/0x5770 kernel/sched/core.c:6625 schedule+0xde/0x1a0 kernel/sched/core.c:6701 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6760 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0xa3b/0x1350 kernel/locking/mutex.c:747 switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:75 process_one_work+0x991/0x15c0 kernel/workqueue.c:2390 worker_thread+0x669/0x1090 kernel/workqueue.c:2537 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 INFO: task syz-executor.4:22496 blocked for more than 144 seconds. Not tainted 6.3.0-rc7-syzkaller-00089-gcb0856346a60 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.4 state:D stack:25072 pid:22496 ppid:1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5307 [inline] __schedule+0xc91/0x5770 kernel/sched/core.c:6625 schedule+0xde/0x1a0 kernel/sched/core.c:6701 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6760 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0xa3b/0x1350 kernel/locking/mutex.c:747 rtnl_lock net/core/rtnetlink.c:75 [inline] rtnetlink_rcv_msg+0x3e8/0xd50 net/core/rtnetlink.c:6178 netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2577 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365 netlink_sendmsg+0x925/0xe30 net/netlink/af_netlink.c:1942 sock_sendmsg_nosec net/socket.c:724 [inline] sock_sendmsg+0xde/0x190 net/socket.c:747 __sys_sendto+0x23a/0x340 net/socket.c:2142 __do_sys_sendto net/socket.c:2154 [inline] __se_sys_sendto net/socket.c:2150 [inline] __x64_sys_sendto+0xe1/0x1b0 net/socket.c:2150 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f7009e3e19c RSP: 002b:00007f700a0cf630 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f700aad4620 RCX: 00007f7009e3e19c RDX: 0000000000000028 RSI: 00007f700aad4670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007f700a0cf684 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007f700aad4670 R14: 0000000000000003 R15: 0000000000000000 INFO: task syz-executor.0:22499 blocked for more than 144 seconds. Not tainted 6.3.0-rc7-syzkaller-00089-gcb0856346a60 #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:24912 pid:22499 ppid:1 flags:0x00000004 Call Trace: context_switch kernel/sched/core.c:5307 [inline] __schedule+0xc91/0x5770 kernel/sched/core.c:6625 schedule+0xde/0x1a0 kernel/sched/core.c:6701 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:6760 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0xa3b/0x1350 kernel/locking/mutex.c:747 rtnl_lock net/core/rtnetlink.c:75 [inline] rtnetlink_rcv_msg+0x3e8/0xd50 net/core/rtnetlink.c:6178 netlink_rcv_skb+0x165/0x440 net/netlink/af_netlink.c:2577 netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline] netlink_unicast+0x547/0x7f0 net/netlink/af_netlink.c:1365 netlink_sendmsg+0x925/0xe30 net/netlink/af_netlink.c:1942 sock_sendmsg_nosec net/socket.c:724 [inline] sock_sendmsg+0xde/0x190 net/socket.c:747 __sys_sendto+0x23a/0x340 net/socket.c:2142 __do_sys_sendto net/socket.c:2154 [inline] __se_sys_sendto net/socket.c:2150 [inline] __x64_sys_sendto+0xe1/0x1b0 net/socket.c:2150 do_syscall_x64 arch/x86/entry/common.c:50 [inline] do_syscall_64+0x39/0xb0 arch/x86/entry/common.c:80 entry_SYSCALL_64_after_hwframe+0x63/0xcd RIP: 0033:0x7f1ab363e19c RSP: 002b:00007f1ab38cf630 EFLAGS: 00000293 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 00007f1ab42d4620 RCX: 00007f1ab363e19c RDX: 0000000000000028 RSI: 00007f1ab42d4670 RDI: 0000000000000003 RBP: 0000000000000000 R08: 00007f1ab38cf684 R09: 000000000000000c R10: 0000000000000000 R11: 0000000000000293 R12: 0000000000000000 R13: 00007f1ab42d4670 R14: 0000000000000003 R15: 0000000000000000 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8c794a70 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x31/0xd80 kernel/rcu/tasks.h:510 1 lock held by rcu_tasks_trace/13: #0: ffffffff8c794770 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x31/0xd80 kernel/rcu/tasks.h:510 1 lock held by khungtaskd/28: #0: ffffffff8c7955c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x55/0x340 kernel/locking/lockdep.c:6495 1 lock held by dhcpcd/4654: #0: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: netlink_dump+0xbe/0xc50 net/netlink/af_netlink.c:2246 2 locks held by getty/4758: #0: ffff888027c65098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x26/0x80 drivers/tty/tty_ldisc.c:244 #1: ffffc900015802f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xef4/0x13e0 drivers/tty/n_tty.c:2177 3 locks held by kworker/0:3/5118: #0: ffff888012470d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888012470d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff888012470d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline] #0: ffff888012470d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:639 [inline] #0: ffff888012470d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:666 [inline] #0: ffff888012470d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x87a/0x15c0 kernel/workqueue.c:2361 #1: ffffc90003f9fda8 ((linkwatch_work).work){+.+.}-{0:0}, at: process_one_work+0x8ae/0x15c0 kernel/workqueue.c:2365 #2: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: linkwatch_event+0xf/0x70 net/core/link_watch.c:277 3 locks held by kworker/0:6/5170: #0: ffff88814a00a538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88814a00a538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff88814a00a538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline] #0: ffff88814a00a538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:639 [inline] #0: ffff88814a00a538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:666 [inline] #0: ffff88814a00a538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x87a/0x15c0 kernel/workqueue.c:2361 #1: ffffc900046afda8 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x15c0 kernel/workqueue.c:2365 #2: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4629 3 locks held by kworker/1:13/9587: #0: ffff88814a00a538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff88814a00a538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff88814a00a538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline] #0: ffff88814a00a538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:639 [inline] #0: ffff88814a00a538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:666 [inline] #0: ffff88814a00a538 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x87a/0x15c0 kernel/workqueue.c:2361 #1: ffffc900149afda8 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x15c0 kernel/workqueue.c:2365 #2: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: addrconf_verify_work+0x12/0x30 net/ipv6/addrconf.c:4629 3 locks held by kworker/u4:11/10014: 5 locks held by kworker/u4:2/3125: #0: ffff888016617138 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888016617138 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff888016617138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline] #0: ffff888016617138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:639 [inline] #0: ffff888016617138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:666 [inline] #0: ffff888016617138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x87a/0x15c0 kernel/workqueue.c:2361 #1: ffffc9000b5a7da8 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x8ae/0x15c0 kernel/workqueue.c:2365 #2: ffffffff8e0e28d0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9f/0xb10 net/core/net_namespace.c:575 #3: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: default_device_exit_batch+0x92/0x5b0 net/core/dev.c:11339 #4: ffffffff8c7a0780 (rcu_state.barrier_mutex){+.+.}-{3:3}, at: rcu_barrier+0x48/0x6a0 kernel/rcu/tree.c:3956 3 locks held by kworker/1:4/14028: #0: ffff888012470d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] #0: ffff888012470d38 ((wq_completion)events){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline] #0: ffff888012470d38 ((wq_completion)events){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline] #0: ffff888012470d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:639 [inline] #0: ffff888012470d38 ((wq_completion)events){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:666 [inline] #0: ffff888012470d38 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x87a/0x15c0 kernel/workqueue.c:2361 #1: ffffc900177e7da8 (deferred_process_work){+.+.}-{0:0}, at: process_one_work+0x8ae/0x15c0 kernel/workqueue.c:2365 #2: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: switchdev_deferred_process_work+0xe/0x20 net/switchdev/switchdev.c:75 1 lock held by syz-executor.4/22496: #0: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:75 [inline] #0: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3e8/0xd50 net/core/rtnetlink.c:6178 1 lock held by syz-executor.0/22499: #0: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: rtnl_lock net/core/rtnetlink.c:75 [inline] #0: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: rtnetlink_rcv_msg+0x3e8/0xd50 net/core/rtnetlink.c:6178 2 locks held by syz-executor.4/22605: #0: ffffffff8e0e28d0 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4cb/0x8e0 net/core/net_namespace.c:486 #1: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x131/0x230 net/smc/smc_pnet.c:878 2 locks held by syz-executor.0/22608: #0: ffffffff8e0e28d0 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4cb/0x8e0 net/core/net_namespace.c:486 #1: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x131/0x230 net/smc/smc_pnet.c:878 2 locks held by syz-executor.4/22612: #0: ffffffff8e0e28d0 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4cb/0x8e0 net/core/net_namespace.c:486 #1: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x131/0x230 net/smc/smc_pnet.c:878 2 locks held by syz-executor.0/22615: #0: ffffffff8e0e28d0 (pernet_ops_rwsem){++++}-{3:3}, at: copy_net_ns+0x4cb/0x8e0 net/core/net_namespace.c:486 #1: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_create_pnetids_list net/smc/smc_pnet.c:809 [inline] #1: ffffffff8e0f6408 (rtnl_mutex){+.+.}-{3:3}, at: smc_pnet_net_init+0x131/0x230 net/smc/smc_pnet.c:878 ============================================= NMI backtrace for cpu 0 CPU: 0 PID: 28 Comm: khungtaskd Not tainted 6.3.0-rc7-syzkaller-00089-gcb0856346a60 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0xd9/0x150 lib/dump_stack.c:106 nmi_cpu_backtrace+0x29c/0x350 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x2a4/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:222 [inline] watchdog+0xe16/0x1090 kernel/hung_task.c:379 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 PID: 10050 Comm: kworker/u4:28 Not tainted 6.3.0-rc7-syzkaller-00089-gcb0856346a60 #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/30/2023 Workqueue: bat_events batadv_nc_worker RIP: 0010:rcu_is_watching+0x0/0xb0 kernel/rcu/tree.c:690 Code: 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 48 c7 c7 00 e8 4d 8a e8 f0 da 93 08 65 8a 05 85 b6 97 7e 0f b6 c0 c3 0f 1f 44 00 00 0f 1e fa 55 53 65 ff 05 0b 9c 97 7e e8 ae da 93 08 48 c7 c3 a8 RSP: 0018:ffffc9000382fc80 EFLAGS: 00000293 RAX: 0000000000000000 RBX: ffff88804376df20 RCX: 0000000000000000 RDX: ffff88802c22ba80 RSI: ffffffff89cc002c RDI: 0000000000000005 RBP: 0000000000000001 R08: 0000000000000005 R09: 0000000000000000 R10: 0000000000000001 R11: 0000000000000000 R12: ffffc9000382fda8 R13: 0000000000000000 R14: dffffc0000000000 R15: 00000000000003e4 FS: 0000000000000000(0000) GS:ffff8880b9900000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c012689160 CR3: 0000000027de0000 CR4: 00000000003506e0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 000000000000000a DR6: 00000000ffff0ff0 DR7: 0000000000000400 Call Trace: rcu_read_lock include/linux/rcupdate.h:774 [inline] batadv_nc_purge_orig_hash net/batman-adv/network-coding.c:408 [inline] batadv_nc_worker+0xbc1/0xfe0 net/batman-adv/network-coding.c:719 process_one_work+0x991/0x15c0 kernel/workqueue.c:2390 worker_thread+0x669/0x1090 kernel/workqueue.c:2537 kthread+0x2e8/0x3a0 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:308 vkms_vblank_simulate: vblank timer overrun