INFO: task hung in console_callback

Status: upstream: reported on 2026/08/04 05:49
Reported-by: syzbot+e82edd5c49e7e3284069@syzkaller.appspotmail.com
First crash: 98d, last: 14d
▶ ▼ Similar bugs (11)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in console_callback serial 1 7 2316d 2484d 0/29 closed as dup on 2020/08/16 15:22
linux-6.6 INFO: task hung in console_callback origin:upstream 1 syz, C inconclusive 2 16d 345d 0/2 upstream: reported C repro on 2025/11/30 20:20
upstream INFO: task hung in console_callback (2) serial 1 1 1709d 1709d 0/29 auto-closed as invalid on 2022/06/05 01:15
linux-4.14 INFO: task hung in console_callback 1 1 2424d 2424d 0/1 auto-closed as invalid on 2020/07/20 15:40
linux-4.19 INFO: task hung in console_callback (2) 1 1 2181d 2181d 0/1 auto-closed as invalid on 2021/03/20 18:26
upstream INFO: task hung in console_callback (6) prio:high input usb 1 syz, C error error 57 77d 483d 0/29 upstream: reported C repro on 2025/07/15 17:43
upstream INFO: task hung in console_callback (4) serial 1 65 1137d 1144d 0/29 auto-obsoleted due to no activity on 2023/12/09 22:03
upstream INFO: task hung in console_callback (5) serial 1 572 595d 714d 0/29 auto-obsoleted due to no activity on 2025/06/03 01:53
linux-6.1 INFO: task hung in console_callback 1 2 103d 105d 0/3 auto-obsoleted due to no activity on 2026/11/07 19:26
upstream INFO: task hung in console_callback (3) serial 1 11 1539d 1583d 0/29 auto-obsoleted due to no activity on 2022/11/22 14:53
linux-4.19 INFO: task hung in console_callback 1 1 2495d 2495d 0/1 auto-closed as invalid on 2020/05/10 04:25

Sample crash report:
INFO: task kworker/0:2:1109 blocked for more than 144 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/0:2     state:D stack:23088 pid: 1109 ppid:     2 flags:0x00004000
Workqueue: events console_callback
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5049 [inline]
 __schedule+0x11c3/0x4350 kernel/sched/core.c:6395
 schedule+0x11b/0x1e0 kernel/sched/core.c:6478
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2093
 __down_common+0x289/0x3b0 kernel/locking/semaphore.c:228
 down+0x7e/0xd0 kernel/locking/semaphore.c:63
 console_lock+0x29/0x70 kernel/printk/printk.c:2557
 console_callback+0x66/0x440 drivers/tty/vt/vt.c:2980
 process_one_work+0x867/0xff0 kernel/workqueue.c:2310
 worker_thread+0xad7/0x12a0 kernel/workqueue.c:2457
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Showing all locks held in the system:
1 lock held by khungtaskd/27:
 #0: ffffffff8d11efa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x0/0x30
4 locks held by kworker/u4:3/413:
2 locks held by kworker/0:2/1109:
 #0: ffff888017870938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x75c/0xff0 kernel/workqueue.c:-1
 #1: ffffc9000469fd00 (console_work){+.+.}-{0:0}, at: process_one_work+0x79e/0xff0 kernel/workqueue.c:2285
4 locks held by kworker/u4:5/4291:
2 locks held by kworker/u4:10/4472:
2 locks held by getty/15271:
 #0: ffff88802cffe098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:252
 #1: ffffc900013482e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x594/0x1a50 drivers/tty/n_tty.c:2158
5 locks held by syz.2.3185/22224:
2 locks held by syz.5.3296/23244:
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline]
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148
 #1: ffff8880768551c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_init_dev+0x6f/0x470 drivers/tty/tty_io.c:1430
1 lock held by syz.1.3314/23559:
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd2/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.8.3320/23650:
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd2/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.9.3321/23649:
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd2/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.3.3348/24680:
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline]
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148
1 lock held by syz.4.3356/25257:
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline]
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148
1 lock held by syz.6.3359/25302:
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline]
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148
3 locks held by kworker/0:13/26677:
1 lock held by syz.1.3412/26725:
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline]
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148
1 lock held by syz.0.3428/27110:
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline]
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148
1 lock held by syz.5.3429/27127:
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd2/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.9.3506/28131:
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline]
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148
1 lock held by syz.4.3534/28519:
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2064 [inline]
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x20a/0xcd0 drivers/tty/tty_io.c:2148
1 lock held by syz.2.3568/28975:
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd2/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.7.3632/29575:
 #0: ffffffff8d7f6648 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xd2/0x2c0 drivers/tty/pty.c:823

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

NMI backtrace for cpu 0
CPU: 0 PID: 27 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 09/16/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x250 lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3a2/0x3d0 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x163/0x280 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xe1b/0xe60 kernel/hung_task.c:369
 kthread+0x42e/0x520 kernel/kthread.c:334
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:287
 </TASK>

Crashes (7):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/10/27 04:51 linux-5.15.y 792fbe1537d8 168cb7a2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in console_callback
2026/10/01 03:14 linux-5.15.y 0248c33e835e 38f7f0d1 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in console_callback
2026/09/26 08:01 linux-5.15.y 0248c33e835e a3c7249d .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in console_callback
2026/09/25 23:53 linux-5.15.y 0248c33e835e f281d9d2 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in console_callback
2026/08/30 11:31 linux-5.15.y 28c35638ec51 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in console_callback
2026/08/04 14:40 linux-5.15.y 6e2fd6534337 d4abbeac .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in console_callback
2026/08/04 05:49 linux-5.15.y 6e2fd6534337 9451e17e .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-5-15-kasan INFO: task hung in console_callback
* Struck through repros no longer work on HEAD.