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| Kernel | Title | Rank 🛈 | Repro | Cause bisect | Fix bisect | Count | Last | Reported | Patched | Status |
|---|---|---|---|---|---|---|---|---|---|---|
| upstream | INFO: task hung in tty_buffer_flush serial | 1 | 6 | 464d | 552d | 0/29 | auto-obsoleted due to no activity on 2025/06/19 19:00 | |||
| upstream | INFO: task hung in tty_buffer_flush (3) prio:high serial | 1 | 2 | 91d | 139d | 0/29 | auto-obsoleted due to no activity on 2026/06/27 15:16 |
INFO: task kworker/0:5:5877 blocked for more than 143 seconds.
Not tainted 6.16.0-rc4-syzkaller-00013-g66701750d556 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:5 state:D stack:21544 pid:5877 tgid:5877 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: events vc_SAK
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5396 [inline]
__schedule+0x116a/0x5de0 kernel/sched/core.c:6785
__schedule_loop kernel/sched/core.c:6863 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6878
schedule_preempt_disabled+0x13/0x30 kernel/sched/core.c:6935
__mutex_lock_common kernel/locking/mutex.c:679 [inline]
__mutex_lock+0x6c7/0xb90 kernel/locking/mutex.c:747
tty_buffer_flush+0x72/0x310 drivers/tty/tty_buffer.c:229
tty_ldisc_flush+0x64/0xe0 drivers/tty/tty_ldisc.c:388
__do_SAK+0x6de/0x880 drivers/tty/tty_io.c:3025
vc_SAK+0x7f/0x310 drivers/tty/vt/vt_ioctl.c:1009
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
process_scheduled_works kernel/workqueue.c:3321 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
kthread+0x3c2/0x780 kernel/kthread.c:464
ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
INFO: task kworker/0:6:5927 blocked for more than 143 seconds.
Not tainted 6.16.0-rc4-syzkaller-00013-g66701750d556 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:6 state:D stack:21784 pid:5927 tgid:5927 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: events console_callback
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5396 [inline]
__schedule+0x116a/0x5de0 kernel/sched/core.c:6785
__schedule_loop kernel/sched/core.c:6863 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6878
schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
___down_common+0x2d8/0x460 kernel/locking/semaphore.c:268
__down_common kernel/locking/semaphore.c:293 [inline]
__down+0x20/0x30 kernel/locking/semaphore.c:303
down+0x74/0xa0 kernel/locking/semaphore.c:100
console_lock+0x5b/0xa0 kernel/printk/printk.c:2849
console_callback+0x62/0x4c0 drivers/tty/vt/vt.c:3202
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
process_scheduled_works kernel/workqueue.c:3321 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
kthread+0x3c2/0x780 kernel/kthread.c:464
ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
INFO: task kworker/u8:22:6749 blocked for more than 143 seconds.
Not tainted 6.16.0-rc4-syzkaller-00013-g66701750d556 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u8:22 state:D stack:25368 pid:6749 tgid:6749 ppid:2 task_flags:0x4208060 flags:0x00004000
Workqueue: events_unbound flush_to_ldisc
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5396 [inline]
__schedule+0x116a/0x5de0 kernel/sched/core.c:6785
__schedule_loop kernel/sched/core.c:6863 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6878
schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
___down_common+0x2d8/0x460 kernel/locking/semaphore.c:268
__down_common kernel/locking/semaphore.c:293 [inline]
__down+0x20/0x30 kernel/locking/semaphore.c:303
down+0x74/0xa0 kernel/locking/semaphore.c:100
console_lock+0x5b/0xa0 kernel/printk/printk.c:2849
do_con_write+0x152/0x8280 drivers/tty/vt/vt.c:3138
con_put_char+0x73/0xa0 drivers/tty/vt/vt.c:3524
tty_put_char+0xbb/0x160 drivers/tty/tty_io.c:3153
n_tty_process_echo_ops drivers/tty/n_tty.c:647 [inline]
__process_echoes+0x812/0xb10 drivers/tty/n_tty.c:693
flush_echoes drivers/tty/n_tty.c:791 [inline]
__receive_buf drivers/tty/n_tty.c:1626 [inline]
n_tty_receive_buf_common+0xa28/0x1980 drivers/tty/n_tty.c:1723
tty_ldisc_receive_buf+0xa7/0x1a0 drivers/tty/tty_buffer.c:387
tty_port_default_receive_buf+0x70/0xb0 drivers/tty/tty_port.c:37
receive_buf drivers/tty/tty_buffer.c:445 [inline]
flush_to_ldisc+0x268/0x780 drivers/tty/tty_buffer.c:495
process_one_work+0x9cf/0x1b70 kernel/workqueue.c:3238
process_scheduled_works kernel/workqueue.c:3321 [inline]
worker_thread+0x6c8/0xf10 kernel/workqueue.c:3402
kthread+0x3c2/0x780 kernel/kthread.c:464
ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
ret_from_fork_asm+0x1a/0x30 arch/x86/entry/entry_64.S:245
</TASK>
INFO: task syz.4.244:7173 blocked for more than 143 seconds.
Not tainted 6.16.0-rc4-syzkaller-00013-g66701750d556 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.244 state:D stack:27560 pid:7173 tgid:7172 ppid:5822 task_flags:0x400140 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5396 [inline]
__schedule+0x116a/0x5de0 kernel/sched/core.c:6785
__schedule_loop kernel/sched/core.c:6863 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6878
schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
___down_common+0x2d8/0x460 kernel/locking/semaphore.c:268
__down_common kernel/locking/semaphore.c:293 [inline]
__down+0x20/0x30 kernel/locking/semaphore.c:303
down+0x74/0xa0 kernel/locking/semaphore.c:100
console_lock+0x5b/0xa0 kernel/printk/printk.c:2849
con_set_unimap+0x74/0x640 drivers/tty/vt/consolemap.c:651
do_unimap_ioctl drivers/tty/vt/vt_ioctl.c:500 [inline]
vt_io_ioctl drivers/tty/vt/vt_ioctl.c:546 [inline]
vt_ioctl+0x1117/0x30a0 drivers/tty/vt/vt_ioctl.c:755
tty_ioctl+0x65e/0x1640 drivers/tty/tty_io.c:2792
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl fs/ioctl.c:893 [inline]
__x64_sys_ioctl+0x18b/0x210 fs/ioctl.c:893
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7fcd6d78e929
RSP: 002b:00007fcd6e5c5038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007fcd6d9b5fa0 RCX: 00007fcd6d78e929
RDX: 0000200000000040 RSI: 0000000000004b67 RDI: 0000000000000006
RBP: 00007fcd6d810b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007fcd6d9b5fa0 R15: 00007fffaa081df8
</TASK>
INFO: task syz.2.257:7246 blocked for more than 143 seconds.
Not tainted 6.16.0-rc4-syzkaller-00013-g66701750d556 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.2.257 state:D stack:25784 pid:7246 tgid:7245 ppid:5820 task_flags:0x400140 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5396 [inline]
__schedule+0x116a/0x5de0 kernel/sched/core.c:6785
__schedule_loop kernel/sched/core.c:6863 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6878
schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
___down_common+0x2d8/0x460 kernel/locking/semaphore.c:268
__down_common kernel/locking/semaphore.c:293 [inline]
__down+0x20/0x30 kernel/locking/semaphore.c:303
down+0x74/0xa0 kernel/locking/semaphore.c:100
console_lock+0x5b/0xa0 kernel/printk/printk.c:2849
vt_k_ioctl drivers/tty/vt/vt_ioctl.c:380 [inline]
vt_ioctl+0xd0d/0x30a0 drivers/tty/vt/vt_ioctl.c:751
tty_ioctl+0x65e/0x1640 drivers/tty/tty_io.c:2792
vfs_ioctl fs/ioctl.c:51 [inline]
__do_sys_ioctl fs/ioctl.c:907 [inline]
__se_sys_ioctl fs/ioctl.c:893 [inline]
__x64_sys_ioctl+0x18b/0x210 fs/ioctl.c:893
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7f867138e929
RSP: 002b:00007f867212e038 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f86715b5fa0 RCX: 00007f867138e929
RDX: 0000000000000002 RSI: 0000000000004b3a RDI: 0000000000000005
RBP: 00007f8671410b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007f86715b5fa0 R15: 00007ffce9693d68
</TASK>
INFO: task syz.3.261:7272 blocked for more than 143 seconds.
Not tainted 6.16.0-rc4-syzkaller-00013-g66701750d556 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.3.261 state:D stack:28712 pid:7272 tgid:7271 ppid:5818 task_flags:0x400040 flags:0x00004004
Call Trace:
<TASK>
context_switch kernel/sched/core.c:5396 [inline]
__schedule+0x116a/0x5de0 kernel/sched/core.c:6785
__schedule_loop kernel/sched/core.c:6863 [inline]
schedule+0xe7/0x3a0 kernel/sched/core.c:6878
schedule_timeout+0x257/0x290 kernel/time/sleep_timeout.c:75
___down_common+0x2d8/0x460 kernel/locking/semaphore.c:268
__down_common kernel/locking/semaphore.c:293 [inline]
__down+0x20/0x30 kernel/locking/semaphore.c:303
down+0x74/0xa0 kernel/locking/semaphore.c:100
console_lock+0x5b/0xa0 kernel/printk/printk.c:2849
vcs_open+0x64/0xc0 drivers/tty/vt/vc_screen.c:763
chrdev_open+0x234/0x6a0 fs/char_dev.c:414
do_dentry_open+0x744/0x1c10 fs/open.c:964
vfs_open+0x82/0x3f0 fs/open.c:1094
do_open fs/namei.c:3896 [inline]
path_openat+0x1de4/0x2cb0 fs/namei.c:4055
do_filp_open+0x20b/0x470 fs/namei.c:4082
do_sys_openat2+0x11b/0x1d0 fs/open.c:1437
do_sys_open fs/open.c:1452 [inline]
__do_sys_openat fs/open.c:1468 [inline]
__se_sys_openat fs/open.c:1463 [inline]
__x64_sys_openat+0x174/0x210 fs/open.c:1463
do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
do_syscall_64+0xcd/0x4c0 arch/x86/entry/syscall_64.c:94
entry_SYSCALL_64_after_hwframe+0x77/0x7f
RIP: 0033:0x7faf0d58e929
RSP: 002b:00007faf0e4c8038 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007faf0d7b5fa0 RCX: 00007faf0d58e929
RDX: 0000000000082840 RSI: 0000200000000180 RDI: 00000000ffffff9c
RBP: 00007faf0d610b39 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00007faf0d7b5fa0 R15: 00007ffe5316a058
</TASK>
INFO: lockdep is turned off.
NMI backtrace for cpu 0
CPU: 0 UID: 0 PID: 31 Comm: khungtaskd Not tainted 6.16.0-rc4-syzkaller-00013-g66701750d556 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
Call Trace:
<TASK>
__dump_stack lib/dump_stack.c:94 [inline]
dump_stack_lvl+0x116/0x1f0 lib/dump_stack.c:120
nmi_cpu_backtrace+0x27b/0x390 lib/nmi_backtrace.c:113
nmi_trigger_cpumask_backtrace+0x29c/0x300 lib/nmi_backtrace.c:62
trigger_all_cpu_backtrace include/linux/nmi.h:158 [inline]
check_hung_uninterruptible_tasks kernel/hung_task.c:307 [inline]
watchdog+0xf70/0x12c0 kernel/hung_task.c:470
kthread+0x3c2/0x780 kernel/kthread.c:464
ret_from_fork+0x5d4/0x6f0 arch/x86/kernel/process.c:148
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: 0 Comm: swapper/1 Not tainted 6.16.0-rc4-syzkaller-00013-g66701750d556 #0 PREEMPT(full)
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
RIP: 0010:pv_native_safe_halt+0xf/0x20 arch/x86/kernel/paravirt.c:82
Code: ab 71 02 c3 cc cc cc cc 0f 1f 00 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 90 f3 0f 1e fa 66 90 0f 00 2d 53 30 29 00 fb f4 <e9> 0c fb 02 00 66 2e 0f 1f 84 00 00 00 00 00 66 90 90 90 90 90 90
RSP: 0018:ffffc90000197df8 EFLAGS: 000002c6
RAX: 00000000009c5b34 RBX: 0000000000000001 RCX: ffffffff8b80dc69
RDX: ffffed10170a6646 RSI: ffffffff8c157c20 RDI: ffffffff8191fc61
RBP: ffffed1003cde488 R08: 0000000000000000 R09: ffffed10170a6645
R10: ffff8880b853322b R11: 0000000000000001 R12: 0000000000000001
R13: ffff88801e6f2440 R14: ffffffff90a80d50 R15: 0000000000000000
FS: 0000000000000000(0000) GS:ffff888124852000(0000) knlGS:0000000000000000
CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f6fda6e0300 CR3: 000000007002d000 CR4: 00000000003526f0
Call Trace:
<TASK>
arch_safe_halt arch/x86/include/asm/paravirt.h:107 [inline]
default_idle+0x13/0x20 arch/x86/kernel/process.c:749
default_idle_call+0x6d/0xb0 kernel/sched/idle.c:117
cpuidle_idle_call kernel/sched/idle.c:185 [inline]
do_idle+0x391/0x510 kernel/sched/idle.c:325
cpu_startup_entry+0x4f/0x60 kernel/sched/idle.c:423
start_secondary+0x21d/0x2b0 arch/x86/kernel/smpboot.c:315
common_startup_64+0x13e/0x148
</TASK>
| Time | Kernel | Commit | Syzkaller | Config | Log | Report | Syz repro | C repro | VM info | Assets (help?) | Manager | Title |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 2025/07/02 11:39 | upstream | 66701750d556 | ffe4b334 | .config | console log | report | info | [disk image] [vmlinux] [kernel image] | ci-upstream-kasan-gce-selinux-root | INFO: task hung in tty_buffer_flush |