INFO: task syz.4.108:6601 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 >[ 307.774873][ T38] "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.108 state:D stack:27328 pid:6601 tgid:6582 ppid:5799 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7241 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1dfe/0x25e0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xb5/0x160 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244 inode_lock include/linux/fs.h:1027 [inline] open_last_lookups fs/namei.c:4537 [inline] path_openat+0xb53/0x3df0 fs/namei.c:4784 do_filp_open+0x1fa/0x410 fs/namei.c:4814 do_sys_openat2+0x121/0x200 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_creat fs/open.c:1514 [inline] __se_sys_creat fs/open.c:1508 [inline] __x64_sys_creat+0x8f/0xc0 fs/open.c:1508 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc11b6ff749 RSP: 002b:00007fc11993d038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 00007fc11b956090 RCX: 00007fc11b6ff749 RDX: 0000000000000000 RSI: 0000000000000012 RDI: 00002000000003c0 RBP: 00007fc11b783f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc11b956128 R14: 00007fc11b956090 R15: 00007fffbfc3e178 INFO: task syz.4.108:6602 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.108 state:D stack:28040 pid:6602 tgid:6582 ppid:5799 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7241 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1dfe/0x25e0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xb5/0x160 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244 inode_lock_nested include/linux/fs.h:1072 [inline] __start_dirop fs/namei.c:2864 [inline] start_dirop fs/namei.c:2875 [inline] filename_create+0x1fb/0x360 fs/namei.c:4879 do_symlinkat+0x120/0x3d0 fs/namei.c:5534 __do_sys_symlink fs/namei.c:5567 [inline] __se_sys_symlink fs/namei.c:5565 [inline] __x64_sys_symlink+0x7a/0x90 fs/namei.c:5565 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc11b6ff749 RSP: 002b:00007fc11991c038 EFLAGS: 00000246 ORIG_RAX: 0000000000000058 RAX: ffffffffffffffda RBX: 00007fc11b956180 RCX: 00007fc11b6ff749 RDX: 0000000000000000 RSI: 00002000000007c0 RDI: 00002000000008c0 RBP: 00007fc11b783f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc11b956218 R14: 00007fc11b956180 R15: 00007fffbfc3e178 INFO: task syz.4.108:6603 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.108 state:D stack:28520 pid:6603 tgid:6582 ppid:5799 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7241 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1dfe/0x25e0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xb5/0x160 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244 inode_lock include/linux/fs.h:1027 [inline] open_last_lookups fs/namei.c:4537 [inline] path_openat+0xb53/0x3df0 fs/namei.c:4784 do_filp_open+0x1fa/0x410 fs/namei.c:4814 do_sys_openat2+0x121/0x200 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_creat fs/open.c:1514 [inline] __se_sys_creat fs/open.c:1508 [inline] __x64_sys_creat+0x8f/0xc0 fs/open.c:1508 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc11b6ff749 RSP: 002b:00007fc1194f9038 EFLAGS: 00000246 ORIG_RAX: 0000000000000055 RAX: ffffffffffffffda RBX: 00007fc11b956270 RCX: 00007fc11b6ff749 RDX: 0000000000000000 RSI: 0000000000000104 RDI: 0000200000000b80 RBP: 00007fc11b783f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc11b956308 R14: 00007fc11b956270 R15: 00007fffbfc3e178 INFO: task syz.4.108:6605 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.108 state:D stack:28456 pid:6605 tgid:6582 ppid:5799 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7241 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1dfe/0x25e0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xb5/0x160 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244 inode_lock include/linux/fs.h:1027 [inline] open_last_lookups fs/namei.c:4537 [inline] path_openat+0xb53/0x3df0 fs/namei.c:4784 do_filp_open+0x1fa/0x410 fs/namei.c:4814 do_sys_openat2+0x121/0x200 fs/open.c:1430 do_sys_open fs/open.c:1436 [inline] __do_sys_openat fs/open.c:1452 [inline] __se_sys_openat fs/open.c:1447 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1447 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc11b6ff749 RSP: 002b:00007fc118cb3038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007fc11b956450 RCX: 00007fc11b6ff749 RDX: 0000000000183341 RSI: 0000200000000780 RDI: ffffffffffffff9c RBP: 00007fc11b783f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc11b9564e8 R14: 00007fc11b956450 R15: 00007fffbfc3e178 INFO: task syz.4.108:6606 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.4.108 state:D stack:26840 pid:6606 tgid:6582 ppid:5799 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5256 [inline] __schedule+0x1480/0x50a0 kernel/sched/core.c:6863 __schedule_loop kernel/sched/core.c:6945 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7241 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1dfe/0x25e0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xb5/0x160 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14f/0x750 kernel/locking/rwbase_rt.c:244 inode_lock_nested include/linux/fs.h:1072 [inline] __start_dirop fs/namei.c:2864 [inline] start_dirop fs/namei.c:2875 [inline] filename_create+0x1fb/0x360 fs/namei.c:4879 do_mknodat+0x181/0x620 fs/namei.c:5026 __do_sys_mknod fs/namei.c:5076 [inline] __se_sys_mknod fs/namei.c:5074 [inline] __x64_sys_mknod+0x8c/0xa0 fs/namei.c:5074 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7fc11b6ff749 RSP: 002b:00007fc118890038 EFLAGS: 00000246 ORIG_RAX: 0000000000000085 RAX: ffffffffffffffda RBX: 00007fc11b956540 RCX: 00007fc11b6ff749 RDX: 0000000000000000 RSI: 0000000008001420 RDI: 0000200000000040 RBP: 00007fc11b783f91 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007fc11b9565d8 R14: 00007fc11b956540 R15: 00007fffbfc3e178 Showing all locks held in the system: 1 lock held by khungtaskd/38: #0: ffffffff8d5ae8c0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8d5ae8c0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:867 [inline] #0: ffffffff8d5ae8c0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 4 locks held by kworker/u8:2/43: #0: ffff8881422e9938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff8881422e9938 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc90000b57b80 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc90000b57b80 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 #2: ffff888142aa40d0 (&type->s_umount_key#59){++++}-{4:4}, at: super_trylock_shared+0x20/0xf0 fs/super.c:563 #3: ffff88804d3232a8 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108 4 locks held by kworker/u8:7/1150: #0: ffff888019ad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff888019ad4938 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc900051efb80 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc900051efb80 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 #2: ffffffff8e898600 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x7b0 net/core/net_namespace.c:670 #3: ffffffff8e8a5738 (rtnl_mutex){+.+.}-{4:4}, at: cfg802154_pernet_exit+0x19/0xe0 net/ieee802154/core.c:351 3 locks held by kworker/u8:16/3538: #0: ffff88814d4bd938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3232 [inline] #0: ffff88814d4bd938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x1770 kernel/workqueue.c:3340 #1: ffffc9000d36fb80 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3233 [inline] #1: ffffc9000d36fb80 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x1770 kernel/workqueue.c:3340 #2: ffffffff8e8a5738 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8e8a5738 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x119/0x15a0 net/ipv6/addrconf.c:4194 2 locks held by dhcpcd/5464: #0: ffffffff8e889798 (vlan_ioctl_mutex){+.+.}-{4:4}, at: sock_ioctl+0x5f1/0x790 net/socket.c:1337 #1: ffffffff8e8a5738 (rtnl_mutex){+.+.}-{4:4}, at: vlan_ioctl_handler+0xd0/0x650 net/8021q/vlan.c:579 2 locks held by getty/5560: #0: ffff88814ebd00a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e7e2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x44f/0x1460 drivers/tty/n_tty.c:2211 4 locks held by syz.4.108/6586: 2 locks held by syz.4.108/6601: #0: ffff888142aa4480 (sb_writers#27){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499 #1: ffff88804d323678 (&type->i_mutex_dir_key#19){++++}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #1: ffff88804d323678 (&type->i_mutex_dir_key#19){++++}-{4:4}, at: open_last_lookups fs/namei.c:4537 [inline] #1: ffff88804d323678 (&type->i_mutex_dir_key#19){++++}-{4:4}, at: path_openat+0xb53/0x3df0 fs/namei.c:4784 2 locks held by syz.4.108/6602: #0: ffff888142aa4480 (sb_writers#27){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499 #1: ffff88804d323678 (&type->i_mutex_dir_key#19/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1072 [inline] #1: ffff88804d323678 (&type->i_mutex_dir_key#19/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2864 [inline] #1: ffff88804d323678 (&type->i_mutex_dir_key#19/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2875 [inline] #1: ffff88804d323678 (&type->i_mutex_dir_key#19/1){+.+.}-{4:4}, at: filename_create+0x1fb/0x360 fs/namei.c:4879 2 locks held by syz.4.108/6603: #0: ffff888142aa4480 (sb_writers#27){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499 #1: ffff88804d323678 (&type->i_mutex_dir_key#19){++++}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #1: ffff88804d323678 (&type->i_mutex_dir_key#19){++++}-{4:4}, at: open_last_lookups fs/namei.c:4537 [inline] #1: ffff88804d323678 (&type->i_mutex_dir_key#19){++++}-{4:4}, at: path_openat+0xb53/0x3df0 fs/namei.c:4784 2 locks held by syz.4.108/6605: #0: ffff888142aa4480 (sb_writers#27){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499 #1: ffff88804d323678 (&type->i_mutex_dir_key#19){++++}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline] #1: ffff88804d323678 (&type->i_mutex_dir_key#19){++++}-{4:4}, at: open_last_lookups fs/namei.c:4537 [inline] #1: ffff88804d323678 (&type->i_mutex_dir_key#19){++++}-{4:4}, at: path_openat+0xb53/0x3df0 fs/namei.c:4784 2 locks held by syz.4.108/6606: #0: ffff888142aa4480 (sb_writers#27){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:499 #1: ffff88804d323678 (&type->i_mutex_dir_key#19/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1072 [inline] #1: ffff88804d323678 (&type->i_mutex_dir_key#19/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2864 [inline] #1: ffff88804d323678 (&type->i_mutex_dir_key#19/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2875 [inline] #1: ffff88804d323678 (&type->i_mutex_dir_key#19/1){+.+.}-{4:4}, at: filename_create+0x1fb/0x360 fs/namei.c:4879 1 lock held by syz-executor/7330: #0: ffffffff8e8a5738 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8e8a5738 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 1 lock held by syz-executor/7333: #0: ffffffff8e8a5738 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #0: ffffffff8e8a5738 (rtnl_mutex){+.+.}-{4:4}, at: inet_rtm_newaddr+0x3b0/0x18b0 net/ipv4/devinet.c:978 7 locks held by syz-executor/7433: 4 locks held by syz-executor/7446: #0: ffff8880348f6480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2681 [inline] #0: ffff8880348f6480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x217/0xb40 fs/read_write.c:682 #1: ffff88805e42cc78 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343 #2: ffff88801dbf9a58 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff88801dbf9a58 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344 #3: ffffffff8e12c5f8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x360 drivers/net/netdevsim/bus.c:234 4 locks held by syz-executor/7448: #0: ffff8880348f6480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2681 [inline] #0: ffff8880348f6480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x217/0xb40 fs/read_write.c:682 #1: ffff88802df8e078 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343 #2: ffff88801dbf9a58 (kn->active#52){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline] #2: ffff88801dbf9a58 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344 #3: ffffffff8e12c5f8 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x360 drivers/net/netdevsim/bus.c:234 ============================================= NMI backtrace for cpu 0 CPU: 0 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 Call Trace: dump_stack_lvl+0x189/0x250 lib/dump_stack.c:120 nmi_cpu_backtrace+0x39e/0x3d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:160 [inline] __sys_info lib/sys_info.c:157 [inline] sys_info+0x135/0x170 lib/sys_info.c:165 check_hung_uninterruptible_tasks kernel/hung_task.c:346 [inline] watchdog+0xf95/0xfe0 kernel/hung_task.c:515 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246 Sending NMI from CPU 0 to CPUs 1: NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 17 Comm: pr/legacy Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025 RIP: 0010:delay_tsc+0x5b/0xc0 arch/x86/lib/delay.c:79 Code: 90 49 89 d7 49 c1 e7 20 49 09 c7 4d 29 f7 49 39 df 73 53 bf 01 00 00 00 e8 52 7e be f6 65 8b 05 1b a9 df 06 85 c0 74 1c f3 90 01 00 00 00 e8 9b 7c be f6 e8 06 77 01 00 39 c5 75 0e 0f 01 f9 RSP: 0018:ffffc900001678d0 EFLAGS: 00000286 RAX: 0000000080000000 RBX: 0000000000000899 RCX: 0000000000000000 RDX: 00000000000000a0 RSI: ffffffff8b3f56c0 RDI: 00000000ffffffff RBP: 0000000000000001 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffffff8ad246c0 R12: 1ffffffff31f11fe R13: 00000000ffffffff R14: 000000a01a99274a R15: 0000000000000392 FS: 0000000000000000(0000) GS:ffff888126e01000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000556d4fcb8528 CR3: 00000000303ae000 CR4: 00000000003526f0 Call Trace: udelay include/asm-generic/delay.h:62 [inline] wait_for_lsr+0x166/0x2f0 drivers/tty/serial/8250/8250_port.c:1967 fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3234 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3257 [inline] serial8250_console_write+0x11bd/0x1b40 drivers/tty/serial/8250/8250_port.c:3342 console_emit_next_record kernel/printk/printk.c:3109 [inline] console_flush_one_record+0x6b5/0xbe0 kernel/printk/printk.c:3215 legacy_kthread_func+0x16f/0x210 kernel/printk/printk.c:3674 kthread+0x711/0x8a0 kernel/kthread.c:463 ret_from_fork+0x599/0xb30 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:246