INFO: task f2fs_writeback-:5886 blocked for more than 143 seconds.
Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:f2fs_writeback- state:D stack:27808 pid:5886 tgid:5886 ppid:2 task_flags:0x200040 flags:0x00080000
Call Trace:
context_switch kernel/sched/core.c:5584 [inline]
__schedule+0x18a6/0x5c10 kernel/sched/core.c:7386
__schedule_loop kernel/sched/core.c:7463 [inline]
schedule+0x164/0x2b0 kernel/sched/core.c:7478
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:7535
rwsem_down_write_slowpath+0x874/0x10d0 kernel/locking/rwsem.c:1215
__down_write_common kernel/locking/rwsem.c:1347 [inline]
__down_write kernel/locking/rwsem.c:1356 [inline]
down_write+0x1b7/0x200 kernel/locking/rwsem.c:1632
f2fs_down_write fs/f2fs/f2fs.h:2544 [inline]
f2fs_down_write_trace+0x34/0x1f0 fs/f2fs/checkpoint.c:181
f2fs_issue_checkpoint+0x414/0x6f0 fs/f2fs/checkpoint.c:2178
f2fs_balance_fs_bg+0x602/0xa50 fs/f2fs/segment.c:561
f2fs_write_node_caches+0xf5/0x3d0 fs/f2fs/node.c:2301
f2fs_cache_writeback_kthread+0x665/0xbb0 fs/f2fs/cache.c:826
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
Showing all locks held in the system:
locks held by kworker/0:1/11: 7, on CPU#0:
#0: ffff888023edfd50 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff888023edfd50 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff888023edfd50 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline]
#0: ffff888023edfd50 ((wq_completion)usb_hub_wq){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594
#1: ffffc90000107c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90000107c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90000107c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline]
#1: ffffc90000107c40 ((work_completion)(&hub->events)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594
#2: ffff88802bad91d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1119 [inline]
#2: ffff88802bad91d8 (&dev->mutex){....}-{4:4}, at: hub_event+0x184/0x4d30 drivers/usb/core/hub.c:5917
#3: ffff8880347851d8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:1119 [inline]
#3: ffff8880347851d8 (&dev->mutex){....}-{4:4}, at: usb_disconnect+0xfc/0x9a0 drivers/usb/core/hub.c:2346
#4: ffff88801d68caa0 (&root->kernfs_supers_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x3f/0x140 fs/kernfs/dir.c:1790
#5: ffff88801d68c980 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_remove_by_name_ns+0x4e/0x140 fs/kernfs/dir.c:1791
#6: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#6: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#6: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: kernfs_should_drain_open_files+0x20/0x2d0 fs/kernfs/file.c:810
locks held by kworker/u8:1/14: 2, last CPU#0:
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline]
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594
#1: ffffc90000137c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90000137c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90000137c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline]
#1: ffffc90000137c40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594
locks held by khungtaskd/35: 1, on CPU#0:
#0: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: debug_show_all_locks+0x2e/0x180 kernel/locking/lockdep.c:6871
locks held by kworker/u8:2/46: 3, on CPU#0:
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline]
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594
#1: ffffc90000b67c40 ((work_completion)(&rdev->wiphy_work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90000b67c40 ((work_completion)(&rdev->wiphy_work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90000b67c40 ((work_completion)(&rdev->wiphy_work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline]
#1: ffffc90000b67c40 ((work_completion)(&rdev->wiphy_work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594
#2: ffff88807c9e0800 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: class_wiphy_constructor include/net/cfg80211.h:6990 [inline]
#2: ffff88807c9e0800 (&rdev->wiphy.mtx){+.+.}-{4:4}, at: cfg80211_wiphy_work+0xb4/0x420 net/wireless/core.c:595
locks held by kworker/u8:4/64: 3, on CPU#0:
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline]
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594
#1: ffffc9000205fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc9000205fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc9000205fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline]
#1: ffffc9000205fc40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594
#2: ffff888033ce4258 (&devlink->lock_key#4){+.+.}-{4:4}, at: nsim_dev_trap_report_work+0x57/0xb30 drivers/net/netdevsim/dev.c:834
locks held by kworker/u8:6/607: 2, last CPU#1:
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline]
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594
#1: ffffc9000323fc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc9000323fc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc9000323fc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline]
#1: ffffc9000323fc40 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594
locks held by kworker/u8:8/1171: 3, on CPU#0:
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline]
#0: ffff88813fe54150 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594
#1: ffffc90005567c40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffc90005567c40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffc90005567c40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_one_work kernel/workqueue.c:3476 [inline]
#1: ffffc90005567c40 ((work_completion)(&(&nsim_dev->trap_data->trap_report_dw)->work)){+.+.}-{0:0}, at: process_scheduled_works+0x97a/0x1630 kernel/workqueue.c:3594
#2: ffff88807f6b1258 (&devlink->lock_key#3){+.+.}-{4:4}, at: nsim_dev_trap_report_work+0x57/0xb30 drivers/net/netdevsim/dev.c:834
locks held by udevd/5003: 3, last CPU#0:
#0: ffff8880367eac00 (&type->i_mutex_dir_key#4){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:1042 [inline]
#0: ffff8880367eac00 (&type->i_mutex_dir_key#4){++++}-{4:4}, at: lookup_slow+0x46/0x80 fs/namei.c:1941
#1: ffff888055e32ac0 (DCACHE_PAR_LOOKUP#5){+.+.}-{0:0}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffff888055e32ac0 (DCACHE_PAR_LOOKUP#5){+.+.}-{0:0}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffff888055e32ac0 (DCACHE_PAR_LOOKUP#5){+.+.}-{0:0}, at: __d_alloc_parallel+0x3a4/0x1740 fs/dcache.c:2891
#2: ffff88801d68c980 (&root->kernfs_rwsem){++++}-{4:4}, at: kernfs_iop_lookup+0x5f/0x320 fs/kernfs/dir.c:1258
locks held by getty/5392: 2, last CPU#1:
#0: ffff888031dcc0a0 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x25/0x70 drivers/tty/tty_ldisc.c:243
#1: ffffc900032362e8 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x45a/0x1360 drivers/tty/n_tty.c:2211
locks held by syz-executor/5632: 2, on CPU#0:
#0: ffff88802d242478 (sb_writers#5){.+.+}-{0:0}, at: mnt_want_write+0x41/0x90 fs/namespace.c:531
#1: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#1: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
locks held by syz-executor/5635: 4, on CPU#0:
#0: ffff888037664100 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock fs/super.c:60 [inline]
#0: ffff888037664100 (&type->s_umount_key#56){+.+.}-{4:4}, at: __super_lock_excl fs/super.c:75 [inline]
#0: ffff888037664100 (&type->s_umount_key#56){+.+.}-{4:4}, at: deactivate_super+0xac/0xe0 fs/super.c:585
#1: ffff888035f94100 (&type->s_umount_key#57){.+.+}-{4:4}, at: ovl_sync_fs+0x116/0x160 fs/overlayfs/super.c:282
#2: ffff888027e194e0 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2544 [inline]
#2: ffff888027e194e0 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write_trace+0x34/0x1f0 fs/f2fs/checkpoint.c:181
#3: ffff888027e18320 (&sbi->cp_global_sem_key){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2544 [inline]
#3: ffff888027e18320 (&sbi->cp_global_sem_key){+.+.}-{4:4}, at: f2fs_down_write_trace+0x34/0x1f0 fs/f2fs/checkpoint.c:181
locks held by f2fs_writeback-/5886: 2, last CPU#0:
#0: ffff888035f94478 (sb_writers#13){.+.+}-{0:0}, at: kthread+0x38b/0x480 kernel/kthread.c:436
#1: ffff888027e194e0 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write fs/f2fs/f2fs.h:2544 [inline]
#1: ffff888027e194e0 (&sbi->gc_lock){+.+.}-{4:4}, at: f2fs_down_write_trace+0x34/0x1f0 fs/f2fs/checkpoint.c:181
locks held by syz-executor/6040: 4, on CPU#1:
#0: ffffffff9023af90 (dup_mmap_sem){.+.+}-{0:0}, at: dup_mm kernel/fork.c:1538 [inline]
#0: ffffffff9023af90 (dup_mmap_sem){.+.+}-{0:0}, at: copy_mm+0xf6/0x640 kernel/fork.c:1604
#1: ffff88801fb42800 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:566 [inline]
#1: ffff88801fb42800 (&mm->mmap_lock){++++}-{4:4}, at: dup_mm kernel/fork.c:1539 [inline]
#1: ffff88801fb42800 (&mm->mmap_lock){++++}-{4:4}, at: copy_mm+0x110/0x640 kernel/fork.c:1604
#2: ffff888077589bc0 (&mm->mmap_lock/1){+.+.}-{4:4}, at: mmap_write_lock_nested include/linux/mmap_lock.h:556 [inline]
#2: ffff888077589bc0 (&mm->mmap_lock/1){+.+.}-{4:4}, at: dup_mmap+0x1f6/0x1c80 mm/mmap.c:1722
#3: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#3: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#3: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: __pte_offset_map+0x29/0x240 mm/pgtable-generic.c:302
locks held by syz.6.361/7733: 2, on CPU#1:
#0: ffff88807df5e478 (sb_writers#5){.+.+}-{0:0}, at: vfs_coredump+0xac3/0x10c0 fs/coredump.c:1312
#1: ffff88805590c590 (&sb->s_type->i_mutex_key#16){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline]
#1: ffff88805590c590 (&sb->s_type->i_mutex_key#16){+.+.}-{4:4}, at: shmem_file_write_iter+0x7f/0x120 mm/shmem.c:3698
locks held by syz.6.368/7791: 2, on CPU#1:
#0: ffff88807f1fa800 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock include/linux/mmap_lock.h:548 [inline]
#0: ffff88807f1fa800 (&mm->mmap_lock){++++}-{4:4}, at: exit_mmap+0x2d5/0xa40 mm/mmap.c:1323
#1: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#1: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: is_module_text_address+0x1d/0x1e0 kernel/module/main.c:3957
locks held by syz.4.378/7788: 1, last CPU#0:
#0: ffff88807758b440 (&mm->mmap_lock){++++}-{4:4}, at: mmap_write_lock_killable include/linux/mmap_lock.h:566 [inline]
#0: ffff88807758b440 (&mm->mmap_lock){++++}-{4:4}, at: vm_mmap_pgoff+0x1ed/0x520 mm/util.c:579
locks held by syz.4.378/7792: 2, on CPU#1:
#0: ffff88807758b440 (&mm->mmap_lock){++++}-{4:4}, at: mmap_read_lock include/linux/mmap_lock.h:616 [inline]
#0: ffff88807758b440 (&mm->mmap_lock){++++}-{4:4}, at: madvise_lock+0x152/0x2e0 mm/madvise.c:1813
#1: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#1: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#1: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: class_rcu_constructor include/linux/rcupdate.h:1216 [inline]
#1: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: unwind_next_frame+0x8f/0x2550 arch/x86/kernel/unwind_orc.c:495
locks held by syz.4.378/7793: 2, on CPU#1:
#0: ffff88802ada6478 (sb_writers#5){.+.+}-{0:0}, at: vfs_coredump+0xac3/0x10c0 fs/coredump.c:1312
#1: ffff88807bd3ea20 (&sb->s_type->i_mutex_key#16){+.+.}-{4:4}, at: inode_lock include/linux/fs.h:1027 [inline]
#1: ffff88807bd3ea20 (&sb->s_type->i_mutex_key#16){+.+.}-{4:4}, at: shmem_file_write_iter+0x7f/0x120 mm/shmem.c:3698
locks held by syz.0.379/7798: 2, last CPU#1:
#0: ffff888034ad1d60 (&rmidi->open_mutex){+.+.}-{4:4}, at: class_mutex_constructor include/linux/mutex.h:253 [inline]
#0: ffff888034ad1d60 (&rmidi->open_mutex){+.+.}-{4:4}, at: snd_rawmidi_release+0x76/0x220 sound/core/rawmidi.c:665
#1: ffffffff901610a8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: exp_funnel_lock kernel/rcu/tree_exp.h:311 [inline]
#1: ffffffff901610a8 (rcu_state.exp_mutex){+.+.}-{4:4}, at: synchronize_rcu_expedited+0x2cb/0x760 kernel/rcu/tree_exp.h:966
locks held by modprobe/7805: 1, on CPU#1:
#0: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire include/linux/rcupdate.h:309 [inline]
#0: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: rcu_read_lock include/linux/rcupdate.h:849 [inline]
#0: ffffffff9015aa20 (rcu_read_lock){....}-{1:3}, at: path_init+0x124/0x1300 fs/namei.c:2695
=============================================
NMI backtrace for cpu 1
CPU: 1 UID: 0 PID: 35 Comm: khungtaskd Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
Call Trace:
dump_stack_lvl+0xe8/0x150 lib/dump_stack.c:120
nmi_cpu_backtrace+0x274/0x2d0 lib/nmi_backtrace.c:123
nmi_trigger_cpumask_backtrace+0x17d/0x390 lib/nmi_backtrace.c:66
trigger_all_cpu_backtrace include/linux/nmi.h:164 [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:377 [inline]
watchdog+0x1073/0x10f0 kernel/hung_task.c:598
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
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: 34 Comm: pr/ttyS0 Not tainted syzkaller #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/06/2026
RIP: 0010:io_serial_in+0x77/0xc0 drivers/tty/serial/8250/8250_port.c:425
Code: e8 6e 37 42 fc 44 89 f9 d3 e3 49 83 c6 40 4c 89 f0 48 c1 e8 03 42 80 3c 20 00 74 08 4c 89 f7 e8 0f 7d ba fc 41 03 1e 89 da ec <0f> b6 c0 5b 41 5c 41 5e 41 5f e9 8a fc 84 06 cc 44 89 f9 80 e1 07
RSP: 0018:ffffc90000aa78b8 EFLAGS: 00000002
RAX: 1ffffffff3842b00 RBX: 00000000000003fd RCX: 0000000000000000
RDX: 00000000000003fd RSI: 0000000000000000 RDI: 0000000000000020
RBP: dffffc0000000000 R08: 0000000000000003 R09: 0000000000000004
R10: dffffc0000000000 R11: ffffffff85871090 R12: dffffc0000000000
R13: 0000000000000000 R14: ffffffff9c215f20 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff8881233f9000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007ffd6ff09ff8 CR3: 0000000034a18000 CR4: 00000000003526f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000001800
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
serial_in drivers/tty/serial/8250/8250.h:134 [inline]
serial_lsr_in drivers/tty/serial/8250/8250.h:156 [inline]
wait_for_lsr+0x184/0x2f0 drivers/tty/serial/8250/8250_port.c:2036
serial8250_fifo_wait_for_lsr_thre drivers/tty/serial/8250/8250_port.c:3294 [inline]
__serial8250_console_fifo_write+0xcd/0x3e0 drivers/tty/serial/8250/8250_port.c:3369
serial8250_console_fifo_write drivers/tty/serial/8250/8250_port.c:3402 [inline]
__serial8250_console_write drivers/tty/serial/8250/8250_port.c:3456 [inline]
serial8250_console_write+0xa7e/0x1200 drivers/tty/serial/8250/8250_port.c:3520
nbcon_emit_next_record+0xef5/0x1a90 kernel/printk/nbcon.c:-1
nbcon_emit_one kernel/printk/nbcon.c:1157 [inline]
nbcon_kthread_func+0x6d9/0x8d0 kernel/printk/nbcon.c:1271
kthread+0x38b/0x480 kernel/kthread.c:436
ret_from_fork+0x514/0xb70 arch/x86/kernel/process.c:158
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245