INFO: task kworker/1:4:3685 blocked for more than 143 seconds. Not tainted 6.1.110-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/1:4 state:D stack:21944 pid:3685 ppid:2 flags:0x00004000 Workqueue: events rfkill_global_led_trigger_worker Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6558 schedule+0xbf/0x180 kernel/sched/core.c:6634 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6693 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x6b9/0xd80 kernel/locking/mutex.c:747 rfkill_global_led_trigger_worker+0x23/0xd0 net/rfkill/core.c:181 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 INFO: task kworker/u4:5:3693 blocked for more than 143 seconds. Not tainted 6.1.110-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u4:5 state:D stack:21376 pid:3693 ppid:2 flags:0x00004000 Workqueue: netns cleanup_net Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6558 schedule+0xbf/0x180 kernel/sched/core.c:6634 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6693 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x6b9/0xd80 kernel/locking/mutex.c:747 rfkill_unregister+0xcc/0x220 net/rfkill/core.c:1130 wiphy_unregister+0x223/0xb10 net/wireless/core.c:1089 ieee80211_unregister_hw+0x1b8/0x290 net/mac80211/main.c:1497 mac80211_hwsim_del_radio+0x2be/0x4a0 drivers/net/wireless/mac80211_hwsim.c:4683 hwsim_exit_net+0x5b8/0x660 drivers/net/wireless/mac80211_hwsim.c:5470 ops_exit_list net/core/net_namespace.c:172 [inline] cleanup_net+0x6ce/0xb60 net/core/net_namespace.c:604 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 INFO: task syz-executor:5249 blocked for more than 143 seconds. Not tainted 6.1.110-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:20472 pid:5249 ppid:1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6558 schedule+0xbf/0x180 kernel/sched/core.c:6634 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6693 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x6b9/0xd80 kernel/locking/mutex.c:747 rfkill_fop_open+0x130/0x680 net/rfkill/core.c:1163 misc_open+0x304/0x380 drivers/char/misc.c:143 chrdev_open+0x54a/0x630 fs/char_dev.c:414 do_dentry_open+0x7f9/0x10f0 fs/open.c:882 do_open fs/namei.c:3628 [inline] path_openat+0x2644/0x2e60 fs/namei.c:3785 do_filp_open+0x230/0x480 fs/namei.c:3812 do_sys_openat2+0x13b/0x4f0 fs/open.c:1318 do_sys_open fs/open.c:1334 [inline] __do_sys_openat fs/open.c:1350 [inline] __se_sys_openat fs/open.c:1345 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1345 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fb62877c890 RSP: 002b:00007ffe25d1e840 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fb62877c890 RDX: 0000000000000002 RSI: 00007fb6287f144e RDI: 00000000ffffff9c RBP: 00007fb6287f144e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000000c R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000000 INFO: task syz-executor:5327 blocked for more than 144 seconds. Not tainted 6.1.110-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:21224 pid:5327 ppid:1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6558 schedule+0xbf/0x180 kernel/sched/core.c:6634 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6693 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x6b9/0xd80 kernel/locking/mutex.c:747 misc_open+0x58/0x380 drivers/char/misc.c:107 chrdev_open+0x54a/0x630 fs/char_dev.c:414 do_dentry_open+0x7f9/0x10f0 fs/open.c:882 do_open fs/namei.c:3628 [inline] path_openat+0x2644/0x2e60 fs/namei.c:3785 do_filp_open+0x230/0x480 fs/namei.c:3812 do_sys_openat2+0x13b/0x4f0 fs/open.c:1318 do_sys_open fs/open.c:1334 [inline] __do_sys_openat fs/open.c:1350 [inline] __se_sys_openat fs/open.c:1345 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1345 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fb9b197c890 RSP: 002b:00007fff827c6df0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fb9b197c890 RDX: 0000000000000002 RSI: 00007fb9b19f144e RDI: 00000000ffffff9c RBP: 00007fb9b19f144e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000000c R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000000 INFO: task syz-executor:5422 blocked for more than 144 seconds. Not tainted 6.1.110-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor state:D stack:21224 pid:5422 ppid:1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6558 schedule+0xbf/0x180 kernel/sched/core.c:6634 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6693 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x6b9/0xd80 kernel/locking/mutex.c:747 misc_open+0x58/0x380 drivers/char/misc.c:107 chrdev_open+0x54a/0x630 fs/char_dev.c:414 do_dentry_open+0x7f9/0x10f0 fs/open.c:882 do_open fs/namei.c:3628 [inline] path_openat+0x2644/0x2e60 fs/namei.c:3785 do_filp_open+0x230/0x480 fs/namei.c:3812 do_sys_openat2+0x13b/0x4f0 fs/open.c:1318 do_sys_open fs/open.c:1334 [inline] __do_sys_openat fs/open.c:1350 [inline] __se_sys_openat fs/open.c:1345 [inline] __x64_sys_openat+0x243/0x290 fs/open.c:1345 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7fdb1ed7c890 RSP: 002b:00007ffc20ce49f0 EFLAGS: 00000293 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 00007fdb1ed7c890 RDX: 0000000000000002 RSI: 00007fdb1edf144e RDI: 00000000ffffff9c RBP: 00007fdb1edf144e R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000293 R12: 000000000000000c R13: 0000000000000003 R14: 0000000000000009 R15: 0000000000000000 INFO: task syz.4.299:5427 blocked for more than 144 seconds. Not tainted 6.1.110-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.299 state:D stack:24160 pid:5427 ppid:3649 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6558 schedule+0xbf/0x180 kernel/sched/core.c:6634 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6693 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x6b9/0xd80 kernel/locking/mutex.c:747 rfkill_unregister+0xcc/0x220 net/rfkill/core.c:1130 nfc_unregister_device+0x92/0x290 net/nfc/core.c:1167 virtual_ncidev_close+0x55/0x90 drivers/nfc/virtual_ncidev.c:170 __fput+0x3f6/0x8d0 fs/file_table.c:320 task_work_run+0x246/0x300 kernel/task_work.c:203 resume_user_mode_work include/linux/resume_user_mode.h:49 [inline] exit_to_user_mode_loop+0xde/0x100 kernel/entry/common.c:177 exit_to_user_mode_prepare+0xb1/0x140 kernel/entry/common.c:210 __syscall_exit_to_user_mode_work kernel/entry/common.c:292 [inline] syscall_exit_to_user_mode+0x60/0x270 kernel/entry/common.c:303 do_syscall_64+0x47/0xb0 arch/x86/entry/common.c:87 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f1cb577def9 RSP: 002b:00007ffcf687bf18 EFLAGS: 00000246 ORIG_RAX: 00000000000001b4 RAX: 0000000000000000 RBX: 00007f1cb5937a80 RCX: 00007f1cb577def9 RDX: 0000000000000000 RSI: 000000000000001e RDI: 0000000000000003 RBP: 00007f1cb5937a80 R08: 0000000000000006 R09: 00007ffcf687c20f R10: 00000000005cb1e0 R11: 0000000000000246 R12: 0000000000045d2f R13: 00007ffcf687c020 R14: 0000000000000fd2 R15: ffffffffffffffff INFO: task syz.3.301:5453 blocked for more than 144 seconds. Not tainted 6.1.110-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.301 state:D stack:25544 pid:5453 ppid:4807 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5241 [inline] __schedule+0x143f/0x4570 kernel/sched/core.c:6558 schedule+0xbf/0x180 kernel/sched/core.c:6634 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6693 __mutex_lock_common kernel/locking/mutex.c:679 [inline] __mutex_lock+0x6b9/0xd80 kernel/locking/mutex.c:747 device_lock include/linux/device.h:837 [inline] nfc_dev_down net/nfc/core.c:143 [inline] nfc_rfkill_set_block+0x4c/0x2f0 net/nfc/core.c:179 rfkill_set_block+0x1e7/0x430 net/rfkill/core.c:345 rfkill_fop_write+0x5b7/0x790 net/rfkill/core.c:1286 vfs_write+0x2d9/0xbc0 fs/read_write.c:582 ksys_write+0x19c/0x2c0 fs/read_write.c:637 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x3b/0xb0 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x68/0xd2 RIP: 0033:0x7f3b6cb7def9 RSP: 002b:00007f3b6c9de038 EFLAGS: 00000246 ORIG_RAX: 0000000000000001 RAX: ffffffffffffffda RBX: 00007f3b6cd36058 RCX: 00007f3b6cb7def9 RDX: 0000000000000008 RSI: 0000000020000080 RDI: 0000000000000008 RBP: 00007f3b6cbf0b76 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 00007f3b6cd36058 R15: 00007ffc19b42028 Showing all locks held in the system: 1 lock held by rcu_tasks_kthre/12: #0: ffffffff8d32b1d0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517 1 lock held by rcu_tasks_trace/13: #0: ffffffff8d32b9d0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x29/0xe30 kernel/rcu/tasks.h:517 1 lock held by khungtaskd/28: #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline] #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline] #0: ffffffff8d32b000 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6494 2 locks held by getty/3400: #0: ffff88802e014098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244 #1: ffffc900031262f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x6a7/0x1db0 drivers/tty/n_tty.c:2198 3 locks held by kworker/1:4/3685: #0: ffff888017c70938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #1: ffffc900044cfd20 ((work_completion)(&rfkill_global_led_trigger_work)){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #2: ffffffff8e7a9088 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_global_led_trigger_worker+0x23/0xd0 net/rfkill/core.c:181 4 locks held by kworker/u4:5/3693: #0: ffff888017e1e938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #1: ffffc900045a7d20 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x7a9/0x11d0 kernel/workqueue.c:2267 #2: ffffffff8e4ed390 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0xf1/0xb60 net/core/net_namespace.c:566 #3: ffffffff8e7a9088 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_unregister+0xcc/0x220 net/rfkill/core.c:1130 2 locks held by kworker/u4:6/3735: 2 locks held by syz-executor/5249: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 #1: ffffffff8e7a9088 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_open+0x130/0x680 net/rfkill/core.c:1163 1 lock held by syz-executor/5327: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 1 lock held by syz-executor/5422: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 2 locks held by syz.4.299/5427: #0: ffff8880213f9100 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline] #0: ffff8880213f9100 (&dev->mutex){....}-{3:3}, at: nfc_unregister_device+0x5f/0x290 net/nfc/core.c:1165 #1: ffffffff8e7a9088 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_unregister+0xcc/0x220 net/rfkill/core.c:1130 2 locks held by syz.3.301/5453: #0: ffffffff8e7a9088 (rfkill_global_mutex){+.+.}-{3:3}, at: rfkill_fop_write+0x1a5/0x790 net/rfkill/core.c:1278 #1: ffff8880213f9100 (&dev->mutex){....}-{3:3}, at: device_lock include/linux/device.h:837 [inline] #1: ffff8880213f9100 (&dev->mutex){....}-{3:3}, at: nfc_dev_down net/nfc/core.c:143 [inline] #1: ffff8880213f9100 (&dev->mutex){....}-{3:3}, at: nfc_rfkill_set_block+0x4c/0x2f0 net/nfc/core.c:179 1 lock held by syz-executor/5567: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 1 lock held by syz-executor/5569: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 1 lock held by syz-executor/5571: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 1 lock held by syz-executor/5573: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 1 lock held by syz-executor/5575: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 1 lock held by syz-executor/5577: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 1 lock held by syz-executor/5579: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 1 lock held by syz-executor/5585: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 1 lock held by syz-executor/5587: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 1 lock held by syz-executor/5589: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 1 lock held by syz-executor/5591: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 1 lock held by syz-executor/5593: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 1 lock held by syz-executor/5595: #0: ffffffff8da7f768 (misc_mtx){+.+.}-{3:3}, at: misc_open+0x58/0x380 drivers/char/misc.c:107 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 28 Comm: khungtaskd Not tainted 6.1.110-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x1e3/0x2cb lib/dump_stack.c:106 nmi_cpu_backtrace+0x4e1/0x560 lib/nmi_backtrace.c:111 nmi_trigger_cpumask_backtrace+0x1ae/0x3f0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline] watchdog+0xf88/0xfd0 kernel/hung_task.c:377 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 PID: 5133 Comm: kworker/0:11 Not tainted 6.1.110-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024 Workqueue: events_power_efficient wg_ratelimiter_gc_entries RIP: 0010:native_irq_disable arch/x86/include/asm/irqflags.h:40 [inline] RIP: 0010:arch_local_irq_disable arch/x86/include/asm/irqflags.h:75 [inline] RIP: 0010:arch_local_irq_save arch/x86/include/asm/irqflags.h:107 [inline] RIP: 0010:lock_acquire+0x1b0/0x5a0 kernel/locking/lockdep.c:5658 Code: 00 00 00 00 00 00 9c 8f 84 24 80 00 00 00 42 80 3c 2b 00 74 08 4c 89 ff e8 8d ac 77 00 48 8d 5c 24 60 4c 8b bc 24 80 00 00 00 48 c7 c7 20 10 0c 8b e8 13 70 3c 09 65 ff 05 0c f4 97 7e 45 31 RSP: 0018:ffffc9000485fa80 EFLAGS: 00000246 RAX: 0000000000000000 RBX: ffffc9000485fae0 RCX: ffffffff816a83db RDX: 0000000000000000 RSI: ffffffff8b5d6da0 RDI: ffffffff8b5d6d60 RBP: ffffc9000485fbe0 R08: dffffc0000000000 R09: fffffbfff1d33c96 R10: 0000000000000000 R11: dffffc0000000001 R12: 1ffff9200090bf58 R13: dffffc0000000000 R14: 0000000000000000 R15: 0000000000000246 FS: 0000000000000000(0000) GS:ffff8880b8e00000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007fcc0690c7dd CR3: 000000000d08e000 CR4: 00000000003506f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 Call Trace: __raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline] _raw_spin_lock+0x2a/0x40 kernel/locking/spinlock.c:154 spin_lock include/linux/spinlock.h:351 [inline] wg_ratelimiter_gc_entries+0x5c/0x470 drivers/net/wireguard/ratelimiter.c:63 process_one_work+0x8a9/0x11d0 kernel/workqueue.c:2292 worker_thread+0xa47/0x1200 kernel/workqueue.c:2439 kthread+0x28d/0x320 kernel/kthread.c:376 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295