INFO: task syz.3.60:6357 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.60 state:D stack:29192 pid:6357 tgid:6356 ppid:5840 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1e04/0x25e0 kernel/locking/rtmutex.c:1760 __rwbase_read_lock+0xbc/0x180 kernel/locking/rwbase_rt.c:114 rwbase_read_lock kernel/locking/rwbase_rt.c:147 [inline] __down_read kernel/locking/rwsem.c:1466 [inline] down_read+0x127/0x1f0 kernel/locking/rwsem.c:1539 __super_lock fs/super.c:59 [inline] super_lock+0x2a9/0x3b0 fs/super.c:121 __iterate_supers+0x126/0x290 fs/super.c:923 ksys_sync+0x94/0x150 fs/sync.c:102 __ia32_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f747f3eebe9 RSP: 002b:00007f747d656038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f747f625fa0 RCX: 00007f747f3eebe9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f747f625fa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f747f626038 R14: 00007f747f625fa0 R15: 00007fffcce27ac8 INFO: task syz.3.60:6358 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.60 state:D stack:29224 pid:6358 tgid:6356 ppid:5840 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1e04/0x25e0 kernel/locking/rtmutex.c:1760 __rwbase_read_lock+0xbc/0x180 kernel/locking/rwbase_rt.c:114 rwbase_read_lock kernel/locking/rwbase_rt.c:147 [inline] __down_read kernel/locking/rwsem.c:1466 [inline] down_read+0x127/0x1f0 kernel/locking/rwsem.c:1539 __super_lock fs/super.c:59 [inline] super_lock+0x2a9/0x3b0 fs/super.c:121 __iterate_supers+0x126/0x290 fs/super.c:923 ksys_sync+0x94/0x150 fs/sync.c:102 __ia32_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f747f3eebe9 RSP: 002b:00007f747d635038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f747f626090 RCX: 00007f747f3eebe9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f747f626090 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f747f626128 R14: 00007f747f626090 R15: 00007fffcce27ac8 INFO: task syz.3.60:6359 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.60 state:D stack:29192 pid:6359 tgid:6356 ppid:5840 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1e04/0x25e0 kernel/locking/rtmutex.c:1760 __rwbase_read_lock+0xbc/0x180 kernel/locking/rwbase_rt.c:114 rwbase_read_lock kernel/locking/rwbase_rt.c:147 [inline] __down_read kernel/locking/rwsem.c:1466 [inline] down_read+0x127/0x1f0 kernel/locking/rwsem.c:1539 __super_lock fs/super.c:59 [inline] super_lock+0x2a9/0x3b0 fs/super.c:121 __iterate_supers+0x126/0x290 fs/super.c:923 ksys_sync+0x94/0x150 fs/sync.c:102 __ia32_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f747f3eebe9 RSP: 002b:00007f747d614038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f747f626180 RCX: 00007f747f3eebe9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f747f626180 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f747f626218 R14: 00007f747f626180 R15: 00007fffcce27ac8 INFO: task syz.3.60:6360 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.60 state:D stack:27544 pid:6360 tgid:6356 ppid:5840 task_flags:0x400040 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1e04/0x25e0 kernel/locking/rtmutex.c:1760 __rwbase_read_lock+0xbc/0x180 kernel/locking/rwbase_rt.c:114 rwbase_read_lock kernel/locking/rwbase_rt.c:147 [inline] __down_read kernel/locking/rwsem.c:1466 [inline] down_read+0x127/0x1f0 kernel/locking/rwsem.c:1539 __super_lock fs/super.c:59 [inline] super_lock+0x2a9/0x3b0 fs/super.c:121 __iterate_supers+0x126/0x290 fs/super.c:923 ksys_sync+0x94/0x150 fs/sync.c:102 __ia32_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f747f3eebe9 RSP: 002b:00007f747d1f1038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f747f626270 RCX: 00007f747f3eebe9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f747f626270 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f747f626308 R14: 00007f747f626270 R15: 00007fffcce27ac8 INFO: task syz.3.60:6361 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.3.60 state:D stack:27400 pid:6361 tgid:6356 ppid:5840 task_flags:0x400140 flags:0x00004004 Call Trace: context_switch kernel/sched/core.c:5357 [inline] __schedule+0x16f3/0x4c20 kernel/sched/core.c:6961 __schedule_loop kernel/sched/core.c:7043 [inline] rt_mutex_schedule+0x77/0xf0 kernel/sched/core.c:7339 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1e04/0x25e0 kernel/locking/rtmutex.c:1760 __rwbase_read_lock+0xbc/0x180 kernel/locking/rwbase_rt.c:114 rwbase_read_lock kernel/locking/rwbase_rt.c:147 [inline] __down_read kernel/locking/rwsem.c:1466 [inline] down_read+0x127/0x1f0 kernel/locking/rwsem.c:1539 __super_lock fs/super.c:59 [inline] super_lock+0x2a9/0x3b0 fs/super.c:121 __iterate_supers+0x126/0x290 fs/super.c:923 ksys_sync+0x94/0x150 fs/sync.c:102 __ia32_sys_sync+0xe/0x20 fs/sync.c:113 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0xfa/0x3b0 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f747f3eebe9 RSP: 002b:00007f747cdce038 EFLAGS: 00000246 ORIG_RAX: 00000000000000a2 RAX: ffffffffffffffda RBX: 00007f747f626360 RCX: 00007f747f3eebe9 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000 RBP: 00007f747f626360 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f747f6263f8 R14: 00007f747f626360 R15: 00007fffcce27ac8 Showing all locks held in the system: 1 lock held by khungtaskd/38: #0: ffffffff8d9a8bc0 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:331 [inline] #0: ffffffff8d9a8bc0 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:841 [inline] #0: ffffffff8d9a8bc0 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 2 locks held by kworker/u8:5/69: 3 locks held by kworker/1:3/1861: 2 locks held by getty/5594: #0: ffff88823bf588a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e762e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x444/0x1410 drivers/tty/n_tty.c:2222 3 locks held by syz-executor/5848: 3 locks held by kworker/1:5/5954: #0: ffff888019898538 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff888019898538 ((wq_completion)events){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc900052e7bc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc900052e7bc0 ((work_completion)(&data->fib_event_work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffff8880305df260 (&data->fib_lock){+.+.}-{4:4}, at: nsim_fib_event_work+0x2ac/0x31b0 drivers/net/netdevsim/fib.c:1490 3 locks held by kworker/u8:13/6107: #0: ffff88802fc9a938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff88802fc9a938 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc90003f2fbc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc90003f2fbc0 ((work_completion)(&(&ifa->dad_work)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #2: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: addrconf_dad_work+0x119/0x15a0 net/ipv6/addrconf.c:4194 6 locks held by kworker/u8:14/6304: #0: ffff88801a6f4138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3211 [inline] #0: ffff88801a6f4138 ((wq_completion)netns){+.+.}-{0:0}, at: process_scheduled_works+0x9b4/0x17b0 kernel/workqueue.c:3319 #1: ffffc90003b6fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3212 [inline] #1: ffffc90003b6fbc0 (net_cleanup_work){+.+.}-{0:0}, at: process_scheduled_works+0x9ef/0x17b0 kernel/workqueue.c:3319 #2: ffffffff8ecc5a20 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf7/0x800 net/core/net_namespace.c:658 #3: ffff88802ed4c0d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline] #3: ffff88802ed4c0d8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline] #3: ffff88802ed4c0d8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0x10a/0x3d0 net/devlink/core.c:506 #4: ffff88802ed4e300 (&devlink->lock_key#15){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline] #4: ffff88802ed4e300 (&devlink->lock_key#15){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline] #4: ffff88802ed4e300 (&devlink->lock_key#15){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0x11c/0x3d0 net/devlink/core.c:506 #5: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock include/linux/rtnetlink.h:130 [inline] #5: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_dev_lock+0x257/0x2f0 net/core/dev.c:2142 1 lock held by syz.3.60/6357: #0: ffff8880301ac0d0 (&type->s_umount_key#66){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff8880301ac0d0 (&type->s_umount_key#66){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 1 lock held by syz.3.60/6358: #0: ffff8880301ac0d0 (&type->s_umount_key#66){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff8880301ac0d0 (&type->s_umount_key#66){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 1 lock held by syz.3.60/6359: #0: ffff8880301ac0d0 (&type->s_umount_key#66){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff8880301ac0d0 (&type->s_umount_key#66){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 1 lock held by syz.3.60/6360: #0: ffff8880301ac0d0 (&type->s_umount_key#66){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff8880301ac0d0 (&type->s_umount_key#66){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 1 lock held by syz.3.60/6361: #0: ffff8880301ac0d0 (&type->s_umount_key#66){++++}-{4:4}, at: __super_lock fs/super.c:59 [inline] #0: ffff8880301ac0d0 (&type->s_umount_key#66){++++}-{4:4}, at: super_lock+0x2a9/0x3b0 fs/super.c:121 1 lock held by syz-executor/6685: 1 lock held by syz-executor/6726: #0: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock net/core/rtnetlink.c:80 [inline] #0: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_nets_lock net/core/rtnetlink.c:341 [inline] #0: ffffffff8ecd2938 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_newlink+0x8db/0x1c70 net/core/rtnetlink.c:4056 5 locks held by syz-executor/6730: #0: ffff888033b70488 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3107 [inline] #0: ffff888033b70488 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x217/0xb40 fs/read_write.c:682 #1: ffff88814dee9c78 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e1/0x4f0 fs/kernfs/file.c:325 #2: ffff88814432e3c8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x204/0x4f0 fs/kernfs/file.c:326 #3: ffffffff8e542278 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x360 drivers/net/netdevsim/bus.c:234 #4: ffff88802ed4c0d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:911 [inline] #4: ffff88802ed4c0d8 (&dev->mutex){....}-{4:4}, at: device_del+0xa9/0x8e0 drivers/base/core.c:3840 4 locks held by syz-executor/6733: #0: ffff888033b70488 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3107 [inline] #0: ffff888033b70488 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x217/0xb40 fs/read_write.c:682 #1: ffff8880278a1c78 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e1/0x4f0 fs/kernfs/file.c:325 #2: ffff88814432e3c8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x204/0x4f0 fs/kernfs/file.c:326 #3: ffffffff8e542278 (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/6737: #0: ffff888033b70488 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:3107 [inline] #0: ffff888033b70488 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x217/0xb40 fs/read_write.c:682 #1: ffff88805d602c78 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1e1/0x4f0 fs/kernfs/file.c:325 #2: ffff88814432e3c8 (kn->active#52){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x204/0x4f0 fs/kernfs/file.c:326 #3: ffffffff8e542278 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd1/0x360 drivers/net/netdevsim/bus.c:234 1 lock held by dhcpcd/6778: #0: ffff888032c54350 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1667 [inline] #0: ffff888032c54350 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xcd0 net/packet/af_packet.c:3251 1 lock held by dhcpcd/6779: #0: ffff888032c70350 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1667 [inline] #0: ffff888032c70350 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xcd0 net/packet/af_packet.c:3251 1 lock held by dhcpcd/6780: #0: ffff888032c74350 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1667 [inline] #0: ffff888032c74350 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xcd0 net/packet/af_packet.c:3251 1 lock held by dhcpcd/6781: #0: ffff88805fc42350 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: lock_sock include/net/sock.h:1667 [inline] #0: ffff88805fc42350 (sk_lock-AF_PACKET){+.+.}-{0:0}, at: packet_do_bind+0x32/0xcd0 net/packet/af_packet.c:3251 1 lock held by dhcpcd/6782: ============================================= NMI backtrace for cpu 1 CPU: 1 UID: 0 PID: 38 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT_{RT,(full)} Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025 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] check_hung_uninterruptible_tasks kernel/hung_task.c:328 [inline] watchdog+0xf93/0xfe0 kernel/hung_task.c:491 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 Sending NMI from CPU 1 to CPUs 0: NMI backtrace for cpu 0 CPU: 0 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 07/12/2025 RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400 Code: e8 8e a5 7f fc 44 89 f9 d3 e3 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 7f df de fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f c3 cc cc cc cc cc 44 89 f9 80 e1 07 RSP: 0018:ffffc90000167890 EFLAGS: 00000202 RAX: 1ffffffff3275200 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffffff993a9850 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffffff853eb920 R12: dffffc0000000000 R13: 0000000000000000 R14: ffffffff993a95c0 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff8881268c1000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000556d30d2d6e8 CR3: 000000000d7a6000 CR4: 00000000003526f0 Call Trace: serial_in drivers/tty/serial/8250/8250.h:137 [inline] serial_lsr_in drivers/tty/serial/8250/8250.h:159 [inline] wait_for_lsr+0x1aa/0x2f0 drivers/tty/serial/8250/8250_port.c:1984 fifo_wait_for_lsr drivers/tty/serial/8250/8250_port.c:3288 [inline] serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3311 [inline] serial8250_console_write+0x11bd/0x1b40 drivers/tty/serial/8250/8250_port.c:3396 console_emit_next_record kernel/printk/printk.c:3118 [inline] console_flush_all+0x698/0xcd0 kernel/printk/printk.c:3226 __console_flush_and_unlock+0xa4/0x240 kernel/printk/printk.c:3285 legacy_kthread_func+0x13b/0x1a0 kernel/printk/printk.c:3638 kthread+0x70e/0x8a0 kernel/kthread.c:463 ret_from_fork+0x3f9/0x770 arch/x86/kernel/process.c:148 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245