syzbot

INFO: task syz.1.18:6068 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.1.18        state:D stack:26880 pid:6068  tgid:6068  ppid:5925   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 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]
 blkdev_fallocate+0x263/0x550 block/fops.c:907
 vfs_fallocate+0x672/0x7f0 fs/open.c:340
 ksys_fallocate fs/open.c:364 [inline]
 __do_sys_fallocate fs/open.c:369 [inline]
 __se_sys_fallocate fs/open.c:367 [inline]
 __x64_sys_fallocate+0xc0/0x110 fs/open.c:367
 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: 0033:0x7f6cd8f1c799
RSP: 002b:00007ffdfa609568 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f6cd9195fa0 RCX: 00007f6cd8f1c799
RDX: 0000000000000000 RSI: 0000000000000011 RDI: 0000000000000003
RBP: 00007f6cd8fb2bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000003fc0000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6cd9195fac R14: 00007f6cd9195fa0 R15: 00007f6cd9195fa0
 </TASK>
INFO: task syz.3.20:6070 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.20        state:D stack:26880 pid:6070  tgid:6070  ppid:5926   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 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]
 blkdev_fallocate+0x263/0x550 block/fops.c:907
 vfs_fallocate+0x672/0x7f0 fs/open.c:340
 ksys_fallocate fs/open.c:364 [inline]
 __do_sys_fallocate fs/open.c:369 [inline]
 __se_sys_fallocate fs/open.c:367 [inline]
 __x64_sys_fallocate+0xc0/0x110 fs/open.c:367
 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: 0033:0x7fce1068c799
RSP: 002b:00007ffecf7d69a8 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007fce10905fa0 RCX: 00007fce1068c799
RDX: 0000000000000000 RSI: 0000000000000011 RDI: 0000000000000003
RBP: 00007fce10722bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000003fc0000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fce10905fac R14: 00007fce10905fa0 R15: 00007fce10905fa0
 </TASK>
INFO: task syz.2.19:6071 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.19        state:D stack:26880 pid:6071  tgid:6071  ppid:5936   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 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]
 blkdev_fallocate+0x263/0x550 block/fops.c:907
 vfs_fallocate+0x672/0x7f0 fs/open.c:340
 ksys_fallocate fs/open.c:364 [inline]
 __do_sys_fallocate fs/open.c:369 [inline]
 __se_sys_fallocate fs/open.c:367 [inline]
 __x64_sys_fallocate+0xc0/0x110 fs/open.c:367
 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: 0033:0x7f850082c799
RSP: 002b:00007ffdb2c616b8 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007f8500aa5fa0 RCX: 00007f850082c799
RDX: 0000000000000000 RSI: 0000000000000011 RDI: 0000000000000003
RBP: 00007f85008c2bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000003fc0000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f8500aa5fac R14: 00007f8500aa5fa0 R15: 00007f8500aa5fa0
 </TASK>
INFO: task syz.4.21:6074 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.21        state:D stack:26880 pid:6074  tgid:6074  ppid:5937   task_flags:0x400040 flags:0x00080002
Call Trace:
 <TASK>
 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]
 blkdev_fallocate+0x263/0x550 block/fops.c:907
 vfs_fallocate+0x672/0x7f0 fs/open.c:340
 ksys_fallocate fs/open.c:364 [inline]
 __do_sys_fallocate fs/open.c:369 [inline]
 __se_sys_fallocate fs/open.c:367 [inline]
 __x64_sys_fallocate+0xc0/0x110 fs/open.c:367
 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: 0033:0x7fd0a469c799
RSP: 002b:00007ffd642f6118 EFLAGS: 00000246 ORIG_RAX: 000000000000011d
RAX: ffffffffffffffda RBX: 00007fd0a4915fa0 RCX: 00007fd0a469c799
RDX: 0000000000000000 RSI: 0000000000000011 RDI: 0000000000000003
RBP: 00007fd0a4732bd9 R08: 0000000000000000 R09: 0000000000000000
R10: 0000003fc0000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007fd0a4915fac R14: 00007fd0a4915fa0 R15: 00007fd0a4915fa0
 </TASK>

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
2 locks held by kworker/u8:6/150:
 #0: ffff888019c44938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3250 [inline]
 #0: ffff888019c44938 ((wq_completion)events_unbound#2){+.+.}-{0:0}, at: process_scheduled_works+0x9ea/0x1830 kernel/workqueue.c:3358
 #1: ffffc90003a7fc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3251 [inline]
 #1: ffffc90003a7fc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0xa25/0x1830 kernel/workqueue.c:3358
2 locks held by getty/5548:
 #0: ffff888027eb80a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
 #1: ffffc90003e832e0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x462/0x13c0 drivers/tty/n_tty.c:2211
3 locks held by syz.0.17/6050:
1 lock held by syz.1.18/6068:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.3.20/6070:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.2.19/6071:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.4.21/6074:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.5.22/6181:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.6.23/6200:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.7.24/6206:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.9.26/6207:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.8.25/6208:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.0.27/6306:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.1.28/6309:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.2.29/6323:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.3.30/6326:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.4.31/6327:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
5 locks held by kworker/u8:14/6328:
1 lock held by syz.5.32/6437:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.6.33/6451:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.7.34/6460:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.8.35/6461:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.9.36/6462:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.0.37/6565:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.1.38/6576:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.2.39/6579:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.3.40/6582:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
1 lock held by syz.4.41/6583:
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: inode_lock include/linux/fs.h:1028 [inline]
 #0: ffff888022454868 (&sb->s_type->i_mutex_key#9){++++}-{4:4}, at: blkdev_fallocate+0x263/0x550 block/fops.c:907
6 locks held by syz-executor/6585:
 #0: ffff8880353d6480 (sb_writers#7){.+.+}-{0:0}, at: file_start_write include/linux/fs.h:2710 [inline]
 #0: ffff8880353d6480 (sb_writers#7){.+.+}-{0:0}, at: vfs_write+0x22d/0xba0 fs/read_write.c:684
 #1: ffff88805d0aac78 (&of->mutex){+.+.}-{4:4}, at: kernfs_fop_write_iter+0x1df/0x540 fs/kernfs/file.c:343
 #2: ffff8880282efe18 (kn->active#57){.+.+}-{0:0}, at: kernfs_get_active_of fs/kernfs/file.c:80 [inline]
 #2: ffff8880282efe18 (kn->active#57){.+.+}-{0:0}, at: kernfs_fop_write_iter+0x232/0x540 fs/kernfs/file.c:344
 #3: ffffffff8e9c7d98 (nsim_bus_dev_list_lock){+.+.}-{4:4}, at: del_device_store+0xd7/0x370 drivers/net/netdevsim/bus.c:234
 #4: ffff8880567730d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:895 [inline]
 #4: ffff8880567730d8 (&dev->mutex){....}-{4:4}, at: __device_driver_lock drivers/base/dd.c:1106 [inline]
 #4: ffff8880567730d8 (&dev->mutex){....}-{4:4}, at: device_release_driver_internal+0xb6/0x870 drivers/base/dd.c:1304
 #5: ffff888034786300 (&devlink->lock_key#17){+.+.}-{4:4}, at: nsim_drv_remove+0x50/0x160 drivers/net/netdevsim/dev.c:1778
1 lock held by syz-executor/6595:
2 locks held by syz-executor/6606:
2 locks held by syz-executor/6611:
 #0: ffffffff8f14bb40 (pernet_ops_rwsem){++++}-{4:4}, at: copy_net_ns+0x4f7/0x730 net/core/net_namespace.c:577
 #1: ffffffff8f15a378 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_net_lock_killable include/linux/rtnetlink.h:145 [inline]
 #1: ffffffff8f15a378 (rtnl_mutex){+.+.}-{4:4}, at: register_netdev+0x18/0x60 net/core/dev.c:11535
1 lock held by modprobe/6616:

=============================================

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:
 <TASK>
 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
 </TASK>
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_out+0x7c/0xc0 drivers/tty/serial/8250/8250_port.c:407
Code: 15 95 fc 44 89 f9 d3 e5 49 83 ee 80 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 ec 23 fb fc 41 03 2e 89 d8 89 ea ee <5b> 41 5c 41 5e 41 5f 5d c3 cc cc cc cc cc 44 89 f9 80 e1 07 38 c1
RSP: 0018:ffffc90000167a30 EFLAGS: 00000202
RAX: 0000000000000020 RBX: 0000000000000020 RCX: 0000000000000000
RDX: 00000000000003f8 RSI: 0000000000000000 RDI: 0000000000000000
RBP: 00000000000003f8 R08: 0000000000000000 R09: 0000000000000000
R10: dffffc0000000000 R11: ffffffff852f3d20 R12: dffffc0000000000
R13: 0000000000000001 R14: ffffffff9994f4a0 R15: 0000000000000000
FS:  0000000000000000(0000) GS:ffff888126440000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f61f5f69000 CR3: 000000007158a000 CR4: 00000000003526f0
Call Trace:
 <TASK>
 serial_port_out include/linux/serial_core.h:811 [inline]
 serial8250_console_putchar drivers/tty/serial/8250/8250_port.c:3192 [inline]
 serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:-1 [inline]
 serial8250_console_write+0x12e1/0x1b90 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
 </TASK>