INFO: task syz-executor.1:6997 blocked for more than 143 seconds. Not tainted 5.10.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.1 state:D stack:11640 pid: 6997 ppid: 1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:3774 [inline] __schedule+0x418/0x900 kernel/sched/core.c:4523 schedule+0x38/0xe0 kernel/sched/core.c:4601 wb_wait_for_completion+0x5b/0x90 fs/fs-writeback.c:209 sync_inodes_sb+0xda/0x460 fs/fs-writeback.c:2559 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x4f/0x80 fs/sync.c:67 generic_shutdown_super+0x1d/0x100 fs/super.c:448 kill_block_super+0x1c/0x40 fs/super.c:1446 deactivate_locked_super+0x24/0x60 fs/super.c:335 cleanup_mnt+0xb3/0x140 fs/namespace.c:1118 task_work_run+0x68/0xb0 kernel/task_work.c:151 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:164 [inline] exit_to_user_mode_prepare+0x211/0x220 kernel/entry/common.c:191 syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:266 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x460887 Code: Unable to access opcode bytes at RIP 0x46085d. RSP: 002b:00007ffe9f46e3d8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 000000000000b8c9 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffe9f46e480 RBP: 0000000000000006 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffe9f46f510 R13: 0000000001a92a60 R14: 0000000000000000 R15: 00007ffe9f46f510 INFO: task syz-executor.0:6998 blocked for more than 143 seconds. Not tainted 5.10.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.0 state:D stack:11384 pid: 6998 ppid: 1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:3774 [inline] __schedule+0x418/0x900 kernel/sched/core.c:4523 schedule+0x38/0xe0 kernel/sched/core.c:4601 wb_wait_for_completion+0x5b/0x90 fs/fs-writeback.c:209 sync_inodes_sb+0xda/0x460 fs/fs-writeback.c:2559 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x4f/0x80 fs/sync.c:67 generic_shutdown_super+0x1d/0x100 fs/super.c:448 kill_block_super+0x1c/0x40 fs/super.c:1446 deactivate_locked_super+0x24/0x60 fs/super.c:335 cleanup_mnt+0xb3/0x140 fs/namespace.c:1118 task_work_run+0x68/0xb0 kernel/task_work.c:151 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:164 [inline] exit_to_user_mode_prepare+0x211/0x220 kernel/entry/common.c:191 syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:266 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x460887 Code: Unable to access opcode bytes at RIP 0x46085d. RSP: 002b:00007ffff68f6c48 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 000000000000b5e6 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffff68f6cf0 RBP: 0000000000000003 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffff68f7d80 R13: 0000000001d73a60 R14: 0000000000000000 R15: 00007ffff68f7d80 INFO: task syz-executor.3:7000 blocked for more than 143 seconds. Not tainted 5.10.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.3 state:D stack:11408 pid: 7000 ppid: 1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:3774 [inline] __schedule+0x418/0x900 kernel/sched/core.c:4523 schedule+0x38/0xe0 kernel/sched/core.c:4601 wb_wait_for_completion+0x5b/0x90 fs/fs-writeback.c:209 sync_inodes_sb+0xda/0x460 fs/fs-writeback.c:2559 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x4f/0x80 fs/sync.c:67 generic_shutdown_super+0x1d/0x100 fs/super.c:448 kill_block_super+0x1c/0x40 fs/super.c:1446 deactivate_locked_super+0x24/0x60 fs/super.c:335 cleanup_mnt+0xb3/0x140 fs/namespace.c:1118 task_work_run+0x68/0xb0 kernel/task_work.c:151 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:164 [inline] exit_to_user_mode_prepare+0x211/0x220 kernel/entry/common.c:191 syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:266 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x460887 Code: Unable to access opcode bytes at RIP 0x46085d. RSP: 002b:00007ffd4f543728 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 000000000000b93f RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffd4f5437d0 RBP: 0000000000000006 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffd4f544860 R13: 00000000019f0a60 R14: 0000000000000000 R15: 00007ffd4f544860 INFO: task syz-executor.2:7001 blocked for more than 143 seconds. Not tainted 5.10.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.2 state:D stack:11640 pid: 7001 ppid: 1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:3774 [inline] __schedule+0x418/0x900 kernel/sched/core.c:4523 schedule+0x38/0xe0 kernel/sched/core.c:4601 wb_wait_for_completion+0x5b/0x90 fs/fs-writeback.c:209 sync_inodes_sb+0xda/0x460 fs/fs-writeback.c:2559 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x4f/0x80 fs/sync.c:67 generic_shutdown_super+0x1d/0x100 fs/super.c:448 kill_block_super+0x1c/0x40 fs/super.c:1446 deactivate_locked_super+0x24/0x60 fs/super.c:335 cleanup_mnt+0xb3/0x140 fs/namespace.c:1118 task_work_run+0x68/0xb0 kernel/task_work.c:151 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:164 [inline] exit_to_user_mode_prepare+0x211/0x220 kernel/entry/common.c:191 syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:266 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x460887 Code: Unable to access opcode bytes at RIP 0x46085d. RSP: 002b:00007ffc0abe5a48 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 000000000000ba40 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffc0abe5af0 RBP: 0000000000000009 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffc0abe6b80 R13: 000000000263ea60 R14: 0000000000000000 R15: 00007ffc0abe6b80 INFO: task syz-executor.5:7004 blocked for more than 144 seconds. Not tainted 5.10.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.5 state:D stack:11536 pid: 7004 ppid: 1 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:3774 [inline] __schedule+0x418/0x900 kernel/sched/core.c:4523 schedule+0x38/0xe0 kernel/sched/core.c:4601 wb_wait_for_completion+0x5b/0x90 fs/fs-writeback.c:209 sync_inodes_sb+0xda/0x460 fs/fs-writeback.c:2559 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x4f/0x80 fs/sync.c:67 generic_shutdown_super+0x1d/0x100 fs/super.c:448 kill_block_super+0x1c/0x40 fs/super.c:1446 deactivate_locked_super+0x24/0x60 fs/super.c:335 cleanup_mnt+0xb3/0x140 fs/namespace.c:1118 task_work_run+0x68/0xb0 kernel/task_work.c:151 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:164 [inline] exit_to_user_mode_prepare+0x211/0x220 kernel/entry/common.c:191 syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:266 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x460887 Code: Unable to access opcode bytes at RIP 0x46085d. RSP: 002b:00007ffef3ffad38 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 000000000000bab5 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffef3ffade0 RBP: 0000000000000006 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffef3ffbe70 R13: 00000000020a7a60 R14: 0000000000000000 R15: 00007ffef3ffbe70 INFO: task syz-executor.4:7005 blocked for more than 144 seconds. Not tainted 5.10.0-rc3-syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz-executor.4 state:D stack:11752 pid: 7005 ppid: 7003 flags:0x00004000 Call Trace: context_switch kernel/sched/core.c:3774 [inline] __schedule+0x418/0x900 kernel/sched/core.c:4523 schedule+0x38/0xe0 kernel/sched/core.c:4601 wb_wait_for_completion+0x5b/0x90 fs/fs-writeback.c:209 sync_inodes_sb+0xda/0x460 fs/fs-writeback.c:2559 __sync_filesystem fs/sync.c:34 [inline] sync_filesystem+0x4f/0x80 fs/sync.c:67 generic_shutdown_super+0x1d/0x100 fs/super.c:448 kill_block_super+0x1c/0x40 fs/super.c:1446 deactivate_locked_super+0x24/0x60 fs/super.c:335 cleanup_mnt+0xb3/0x140 fs/namespace.c:1118 task_work_run+0x68/0xb0 kernel/task_work.c:151 tracehook_notify_resume include/linux/tracehook.h:188 [inline] exit_to_user_mode_loop kernel/entry/common.c:164 [inline] exit_to_user_mode_prepare+0x211/0x220 kernel/entry/common.c:191 syscall_exit_to_user_mode+0x7a/0x2c0 kernel/entry/common.c:266 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x460887 Code: Unable to access opcode bytes at RIP 0x46085d. RSP: 002b:00007ffcf5b877a8 EFLAGS: 00000246 ORIG_RAX: 00000000000000a6 RAX: 0000000000000000 RBX: 000000000000bb92 RCX: 0000000000460887 RDX: 0000000000403188 RSI: 0000000000000002 RDI: 00007ffcf5b87850 RBP: 0000000000000009 R08: 0000000000000000 R09: 0000000000000009 R10: 0000000000000005 R11: 0000000000000246 R12: 00007ffcf5b888e0 R13: 0000000001901a60 R14: 0000000000000000 R15: 00007ffcf5b888e0 Showing all locks held in the system: 2 locks held by kworker/u4:0/7: #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x1e6/0x600 kernel/workqueue.c:2243 #1: ffffc90000ca3e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #1: ffffc90000ca3e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #1: ffffc90000ca3e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x1e6/0x600 kernel/workqueue.c:2243 2 locks held by kworker/u4:2/60: #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x1e6/0x600 kernel/workqueue.c:2243 #1: ffffc90000d67e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #1: ffffc90000d67e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #1: ffffc90000d67e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x1e6/0x600 kernel/workqueue.c:2243 2 locks held by kworker/u4:3/288: #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x1e6/0x600 kernel/workqueue.c:2243 #1: ffffc900014b7e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #1: ffffc900014b7e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #1: ffffc900014b7e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x1e6/0x600 kernel/workqueue.c:2243 2 locks held by kworker/u4:4/587: #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x1e6/0x600 kernel/workqueue.c:2243 #1: ffffc90001de7e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #1: ffffc90001de7e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #1: ffffc90001de7e70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x1e6/0x600 kernel/workqueue.c:2243 1 lock held by khungtaskd/1168: #0: ffffffff847fbd40 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x15/0x17a kernel/locking/lockdep.c:6254 1 lock held by in:imklog/6454: #0: ffff88810b8a98f0 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0x45/0x50 fs/file.c:932 2 locks held by syz-executor.1/6997: #0: ffff88811f24d0e0 (&type->s_umount_key#65){+.+.}-{3:3}, at: deactivate_super+0x3e/0x50 fs/super.c:365 #1: ffff8881012b9708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:344 [inline] #1: ffff8881012b9708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0xc0/0x460 fs/fs-writeback.c:2557 2 locks held by syz-executor.0/6998: #0: ffff88811ef870e0 (&type->s_umount_key#65){+.+.}-{3:3}, at: deactivate_super+0x3e/0x50 fs/super.c:365 #1: ffff888100dd7708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:344 [inline] #1: ffff888100dd7708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0xc0/0x460 fs/fs-writeback.c:2557 2 locks held by syz-executor.3/7000: #0: ffff88811f3ab0e0 (&type->s_umount_key#65){+.+.}-{3:3}, at: deactivate_super+0x3e/0x50 fs/super.c:365 #1: ffff888100e3c708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:344 [inline] #1: ffff888100e3c708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0xc0/0x460 fs/fs-writeback.c:2557 2 locks held by syz-executor.2/7001: #0: ffff88811eea80e0 (&type->s_umount_key#65){+.+.}-{3:3}, at: deactivate_super+0x3e/0x50 fs/super.c:365 #1: ffff88810123f708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:344 [inline] #1: ffff88810123f708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0xc0/0x460 fs/fs-writeback.c:2557 2 locks held by syz-executor.5/7004: #0: ffff88811ef310e0 (&type->s_umount_key#65){+.+.}-{3:3}, at: deactivate_super+0x3e/0x50 fs/super.c:365 #1: ffff888100fcf708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:344 [inline] #1: ffff888100fcf708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0xc0/0x460 fs/fs-writeback.c:2557 2 locks held by syz-executor.4/7005: #0: ffff88811ef2e0e0 (&type->s_umount_key#65){+.+.}-{3:3}, at: deactivate_super+0x3e/0x50 fs/super.c:365 #1: ffff888101068708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: bdi_down_write_wb_switch_rwsem fs/fs-writeback.c:344 [inline] #1: ffff888101068708 (&bdi->wb_switch_rwsem){+.+.}-{3:3}, at: sync_inodes_sb+0xc0/0x460 fs/fs-writeback.c:2557 2 locks held by kworker/u4:6/8392: #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x1e6/0x600 kernel/workqueue.c:2243 #1: ffffc9000265fe70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #1: ffffc9000265fe70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #1: ffffc9000265fe70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x1e6/0x600 kernel/workqueue.c:2243 2 locks held by kworker/u4:7/8500: #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #0: ffff888100ef7538 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work+0x1e6/0x600 kernel/workqueue.c:2243 #1: ffffc900026dfe70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:615 [inline] #1: ffffc900026dfe70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline] #1: ffffc900026dfe70 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work+0x1e6/0x600 kernel/workqueue.c:2243 2 locks held by kworker/u4:8/8512: #0: ffff88813bc2df58 (&rq->lock){-.-.}-{2:2}, at: newidle_balance+0x43a/0x650 kernel/sched/fair.c:10576 #1: ffffffff847fbd40 (rcu_read_lock){....}-{1:2}, at: __update_idle_core+0x0/0x270 kernel/sched/fair.c:5215 ============================================= NMI backtrace for cpu 1 CPU: 1 PID: 1168 Comm: khungtaskd Not tainted 5.10.0-rc3-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0xa3/0xc8 lib/dump_stack.c:118 nmi_cpu_backtrace.cold.8+0x53/0x6d lib/nmi_backtrace.c:105 nmi_trigger_cpumask_backtrace+0xd5/0xf0 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline] check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline] watchdog+0x57f/0x670 kernel/hung_task.c:294 kthread+0x145/0x170 kernel/kthread.c:292 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:296 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0xe/0x10 arch/x86/include/asm/irqflags.h:60