INFO: task kworker/u8:7:162 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:kworker/u8:7 state:D stack:21344 pid:162 tgid:162 ppid:2 task_flags:0x4208060 flags:0x00080000 Workqueue: writeback wb_workfn (flush-7:1) Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x14fb/0x52c0 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7285 rt_mutex_slowlock_block+0x508/0x680 kernel/locking/rtmutex.c:1647 __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked kernel/locking/rtmutex.c:1760 [inline] rt_mutex_slowlock+0x2dc/0x7b0 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] __mutex_lock_common kernel/locking/rtmutex_api.c:534 [inline] mutex_lock_nested+0x168/0x1d0 kernel/locking/rtmutex_api.c:552 jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108 jfs_write_inode+0x145/0x220 fs/jfs/inode.c:138 write_inode fs/fs-writeback.c:1582 [inline] __writeback_single_inode+0x75d/0x11a0 fs/fs-writeback.c:1813 writeback_sb_inodes+0x944/0x1970 fs/fs-writeback.c:2041 wb_writeback+0x456/0xb70 fs/fs-writeback.c:2227 wb_do_writeback fs/fs-writeback.c:2374 [inline] wb_workfn+0x41a/0xf60 fs/fs-writeback.c:2414 process_one_work kernel/workqueue.c:3275 [inline] process_scheduled_works+0xb02/0x1830 kernel/workqueue.c:3358 worker_thread+0xa50/0xfc0 kernel/workqueue.c:3439 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 INFO: task syz.1.837:12407 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.837 state:D stack:29024 pid:12407 tgid:12369 ppid:7806 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x14fb/0x52c0 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7285 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244 inode_lock_nested include/linux/fs.h:1073 [inline] lock_rename fs/namei.c:3756 [inline] __start_renaming+0x148/0x410 fs/namei.c:3852 filename_renameat2+0x38c/0x9c0 fs/namei.c:6119 __do_sys_rename fs/namei.c:6188 [inline] __se_sys_rename+0x55/0x2c0 fs/namei.c:6184 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f585e93c629 RSP: 002b:00007f585cb75028 EFLAGS: 00000246 ORIG_RAX: 0000000000000052 RAX: ffffffffffffffda RBX: 00007f585ebb6090 RCX: 00007f585e93c629 RDX: 0000000000000000 RSI: 00002000000002c0 RDI: 0000200000000580 RBP: 00007f585e9d2b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f585ebb6128 R14: 00007f585ebb6090 R15: 00007ffeb474cb28 INFO: task syz.1.837:12408 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.837 state:D stack:29024 pid:12408 tgid:12369 ppid:7806 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x14fb/0x52c0 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7285 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244 inode_lock_nested include/linux/fs.h:1073 [inline] __start_dirop fs/namei.c:2923 [inline] start_dirop fs/namei.c:2934 [inline] filename_create+0x200/0x370 fs/namei.c:4922 filename_mkdirat+0xd2/0x520 fs/namei.c:5259 __do_sys_mkdirat fs/namei.c:5287 [inline] __se_sys_mkdirat+0x35/0x150 fs/namei.c:5284 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f585e93c629 RSP: 002b:00007f585cb54028 EFLAGS: 00000246 ORIG_RAX: 0000000000000102 RAX: ffffffffffffffda RBX: 00007f585ebb6180 RCX: 00007f585e93c629 RDX: 0000000000000000 RSI: 0000200000000280 RDI: ffffffffffffff9c RBP: 00007f585e9d2b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f585ebb6218 R14: 00007f585ebb6180 R15: 00007ffeb474cb28 INFO: task syz.1.837:12410 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.837 state:D stack:28096 pid:12410 tgid:12369 ppid:7806 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x14fb/0x52c0 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7285 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760 __rwbase_read_lock+0xc3/0x180 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+0x132/0x200 kernel/locking/rwsem.c:1539 inode_lock_shared include/linux/fs.h:1043 [inline] lookup_slow+0x46/0x70 fs/namei.c:1932 walk_component fs/namei.c:2279 [inline] lookup_last fs/namei.c:2780 [inline] path_lookupat+0x3f5/0x8c0 fs/namei.c:2804 filename_lookup+0x256/0x5d0 fs/namei.c:2833 user_path_at+0x40/0x160 fs/namei.c:3612 do_mount fs/namespace.c:4156 [inline] __do_sys_mount fs/namespace.c:4348 [inline] __se_sys_mount+0x2dc/0x420 fs/namespace.c:4325 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f585e93c629 RSP: 002b:00007f585c731028 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f585ebb6270 RCX: 00007f585e93c629 RDX: 0000200000002100 RSI: 00002000000020c0 RDI: 0000000000000000 RBP: 00007f585e9d2b39 R08: 0000200000002140 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f585ebb6308 R14: 00007f585ebb6270 R15: 00007ffeb474cb28 INFO: task syz.1.837:12412 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.837 state:D stack:28592 pid:12412 tgid:12369 ppid:7806 task_flags:0x400040 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x14fb/0x52c0 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] rt_mutex_schedule+0x76/0xf0 kernel/sched/core.c:7285 rt_mutex_slowlock_block kernel/locking/rtmutex.c:1647 [inline] __rt_mutex_slowlock kernel/locking/rtmutex.c:1721 [inline] __rt_mutex_slowlock_locked+0x1f8f/0x25c0 kernel/locking/rtmutex.c:1760 rt_mutex_slowlock+0xbd/0x170 kernel/locking/rtmutex.c:1800 __rt_mutex_lock kernel/locking/rtmutex.c:1815 [inline] rwbase_write_lock+0x14d/0x730 kernel/locking/rwbase_rt.c:244 inode_lock include/linux/fs.h:1028 [inline] open_last_lookups fs/namei.c:4580 [inline] path_openat+0xb5e/0x38a0 fs/namei.c:4827 do_file_open+0x23e/0x4a0 fs/namei.c:4859 do_sys_openat2+0x113/0x200 fs/open.c:1366 do_sys_open fs/open.c:1372 [inline] __do_sys_openat fs/open.c:1388 [inline] __se_sys_openat fs/open.c:1383 [inline] __x64_sys_openat+0x138/0x170 fs/open.c:1383 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f585e93c629 RSP: 002b:00007f585c30e028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101 RAX: ffffffffffffffda RBX: 00007f585ebb6360 RCX: 00007f585e93c629 RDX: 000000000000275a RSI: 0000200000000200 RDI: ffffffffffffff9c RBP: 00007f585e9d2b39 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000 R13: 00007f585ebb63f8 R14: 00007f585ebb6360 R15: 00007ffeb474cb28 INFO: task syz.1.837:12413 blocked for more than 143 seconds. Not tainted syzkaller #0 "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. task:syz.1.837 state:D stack:26688 pid:12413 tgid:12369 ppid:7806 task_flags:0x400140 flags:0x00080002 Call Trace: context_switch kernel/sched/core.c:5295 [inline] __schedule+0x14fb/0x52c0 kernel/sched/core.c:6907 __schedule_loop kernel/sched/core.c:6989 [inline] schedule+0x164/0x360 kernel/sched/core.c:7004 wb_wait_for_completion+0x372/0x690 fs/fs-writeback.c:226 __writeback_inodes_sb_nr+0x24c/0x2d0 fs/fs-writeback.c:2838 sync_filesystem+0xa2/0x250 fs/sync.c:54 jfs_reconfigure+0xc6/0xa00 fs/jfs/super.c:370 reconfigure_super+0x227/0x8a0 fs/super.c:1080 do_remount fs/namespace.c:3388 [inline] path_mount+0xdc5/0x10e0 fs/namespace.c:4138 do_mount fs/namespace.c:4159 [inline] __do_sys_mount fs/namespace.c:4348 [inline] __se_sys_mount+0x31d/0x420 fs/namespace.c:4325 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x14d/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x77/0x7f RIP: 0033:0x7f585e93d8ca RSP: 002b:00007f585beeae58 EFLAGS: 00000246 ORIG_RAX: 00000000000000a5 RAX: ffffffffffffffda RBX: 00007f585beeaee0 RCX: 00007f585e93d8ca RDX: 00002000000000c0 RSI: 0000200000002680 RDI: 0000000000000000 RBP: 00002000000000c0 R08: 00007f585beeaee0 R09: 00000000000000a0 R10: 00000000000000a0 R11: 0000000000000246 R12: 0000200000002680 R13: 00007f585beeaea0 R14: 0000000000000000 R15: 00002000000008c0 Showing all locks held in the system: 1 lock held by khungtaskd/38: #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:312 [inline] #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:850 [inline] #0: ffffffff8ddcd780 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6775 3 locks held by kworker/u8:7/162: #0: ffff88801aedc138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline] #0: ffff88801aedc138 ((wq_completion)writeback){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358 #1: ffffc90003b47c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline] #1: ffffc90003b47c40 ((work_completion)(&(&wb->dwork)->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358 #2: ffff888040fe0ba8 (&jfs_ip->commit_mutex){+.+.}-{4:4}, at: jfs_commit_inode+0x1ca/0x530 fs/jfs/inode.c:108 5 locks held by kworker/u8:11/1389: 2 locks held by getty/5553: #0: ffff8880371160a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243 #1: ffffc90003e8b2e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211 2 locks held by kworker/0:4/5804: 7 locks held by udevd/5919: 1 lock held by udevd/5928: #0: ffff8880226f1568 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline] #0: ffff8880226f1568 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_read_iter+0x2ff/0x440 block/fops.c:855 4 locks held by syz.1.837/12370: 2 locks held by syz.1.837/12407: #0: ffff888031782480 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff888040fe0f78 (&type->i_mutex_dir_key#13/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #1: ffff888040fe0f78 (&type->i_mutex_dir_key#13/1){+.+.}-{4:4}, at: lock_rename fs/namei.c:3756 [inline] #1: ffff888040fe0f78 (&type->i_mutex_dir_key#13/1){+.+.}-{4:4}, at: __start_renaming+0x148/0x410 fs/namei.c:3852 2 locks held by syz.1.837/12408: #0: ffff888031782480 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff888040fe0f78 (&type->i_mutex_dir_key#13/1){+.+.}-{4:4}, at: inode_lock_nested include/linux/fs.h:1073 [inline] #1: ffff888040fe0f78 (&type->i_mutex_dir_key#13/1){+.+.}-{4:4}, at: __start_dirop fs/namei.c:2923 [inline] #1: ffff888040fe0f78 (&type->i_mutex_dir_key#13/1){+.+.}-{4:4}, at: start_dirop fs/namei.c:2934 [inline] #1: ffff888040fe0f78 (&type->i_mutex_dir_key#13/1){+.+.}-{4:4}, at: filename_create+0x200/0x370 fs/namei.c:4922 1 lock held by syz.1.837/12410: #0: ffff888040fe0f78 (&type->i_mutex_dir_key#13){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1043 [inline] #0: ffff888040fe0f78 (&type->i_mutex_dir_key#13){++++}-{4:4}, at: lookup_slow+0x46/0x70 fs/namei.c:1932 2 locks held by syz.1.837/12412: #0: ffff888031782480 (sb_writers#17){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:493 #1: ffff888040fe0f78 (&type->i_mutex_dir_key#13){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline] #1: ffff888040fe0f78 (&type->i_mutex_dir_key#13){++++}-{4:4}, at: open_last_lookups fs/namei.c:4580 [inline] #1: ffff888040fe0f78 (&type->i_mutex_dir_key#13){++++}-{4:4}, at: path_openat+0xb5e/0x38a0 fs/namei.c:4827 1 lock held by syz.1.837/12413: #0: ffff8880317820d0 (&type->s_umount_key#63){++++}-{4:4}, at: do_remount fs/namespace.c:3385 [inline] #0: ffff8880317820d0 (&type->s_umount_key#63){++++}-{4:4}, at: path_mount+0xd7d/0x10e0 fs/namespace.c:4138 4 locks held by syz-executor/13306: #0: ffff8880294d80d0 (&type->s_umount_key#56){++++}-{4:4}, at: __super_lock fs/super.c:58 [inline] #0: ffff8880294d80d0 (&type->s_umount_key#56){++++}-{4:4}, at: __super_lock_excl fs/super.c:73 [inline] #0: ffff8880294d80d0 (&type->s_umount_key#56){++++}-{4:4}, at: deactivate_super+0xa9/0xe0 fs/super.c:508 #1: ffff88807c4b31e0 (btrfs_trans_completed){.+.+}-{0:0}, at: btrfs_commit_transaction+0x1a2/0x31a0 fs/btrfs/transaction.c:2215 #2: ffff88807c4b31b8 (btrfs_trans_super_committed){.+.+}-{0:0}, at: btrfs_commit_transaction+0x1a2/0x31a0 fs/btrfs/transaction.c:2215 #3: ffff88807c4b0d18 (&fs_info->tree_log_mutex){+.+.}-{4:4}, at: btrfs_commit_transaction+0x1c4c/0x31a0 fs/btrfs/transaction.c:2537 1 lock held by syz.3.1070/14041: #0: ffff8880317820d0 (&type->s_umount_key#63){++++}-{4:4}, at: __super_lock fs/super.c:60 [inline] #0: ffff8880317820d0 (&type->s_umount_key#63){++++}-{4:4}, at: super_lock+0x2d6/0x3d0 fs/super.c:122 4 locks held by syz.2.1100/14250: 3 locks held by syz-executor/14261: 1 lock held by syz.8.1103/14285: #0: ffff888038dda0d0 (&type->s_umount_key#51/1){+.+.}-{4:4}, at: alloc_super+0x28c/0xac0 fs/super.c:345 4 locks held by udevadm/14322: 3 locks held by syz.0.1107/14338: 3 locks held by dhcpcd-run-hook/14339: ============================================= 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 02/12/2026 Call Trace: dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120 nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:113 nmi_trigger_cpumask_backtrace+0x17a/0x300 lib/nmi_backtrace.c:62 trigger_all_cpu_backtrace include/linux/nmi.h:161 [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+0xfd9/0x1030 kernel/hung_task.c:515 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245 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 02/12/2026 RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:400 Code: e8 2e 1a 95 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 cf 26 fb fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 0a 79 f6 05 cc 44 89 f9 80 e1 07 RSP: 0018:ffffc900001679d0 EFLAGS: 00000202 RAX: 1ffffffff3329a00 RBX: 00000000000003fd RCX: 0000000000000000 RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000000 RBP: ffffffff9994d6f0 R08: 0000000000000000 R09: 0000000000000000 R10: dffffc0000000000 R11: ffffffff852f3990 R12: dffffc0000000000 R13: 0000000000000000 R14: ffffffff9994d460 R15: 0000000000000000 FS: 0000000000000000(0000) GS:ffff888126442000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 00007f9ee2ac7e9c CR3: 000000005a46c000 CR4: 00000000003526f0 Call Trace: serial_in drivers/tty/serial/8250/8250.h:128 [inline] serial_lsr_in drivers/tty/serial/8250/8250.h:150 [inline] wait_for_lsr+0x1aa/0x2f0 drivers/tty/serial/8250/8250_port.c:1961 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+0x120d/0x1b90 drivers/tty/serial/8250/8250_port.c:3342 console_emit_next_record kernel/printk/printk.c:3163 [inline] console_flush_one_record+0x68b/0xb90 kernel/printk/printk.c:3269 legacy_kthread_func+0x1b6/0x250 kernel/printk/printk.c:3712 kthread+0x388/0x470 kernel/kthread.c:467 ret_from_fork+0x51e/0xb90 arch/x86/kernel/process.c:158 ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245