INFO: task hung in con_install

Status: upstream: reported on 2026/07/31 03:32
Reported-by: syzbot+2aa6ad378b756ba27c7f@syzkaller.appspotmail.com
First crash: 35d, last: 22h07m
▶ ▼ Similar bugs (8)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-5.15 INFO: task hung in con_install 1 10 8d20h 41d 0/3 upstream: reported on 2026/07/25 09:43
linux-6.6 INFO: task hung in con_install 1 1 30d 30d 0/2 upstream: reported on 2026/08/05 04:34
upstream INFO: task hung in con_install (2) serial 1 1 1129d 1129d 0/29 auto-obsoleted due to no activity on 2023/10/31 16:25
linux-4.14 INFO: task hung in con_install 1 1 2330d 2330d 0/1 auto-closed as invalid on 2020/08/16 15:03
linux-4.19 INFO: task hung in con_install (2) 1 1 2276d 2276d 0/1 auto-closed as invalid on 2020/10/09 22:35
upstream INFO: task hung in con_install (3) prio:high kernel 1 122 9d23h 234d 0/29 upstream: reported on 2026/01/13 11:30
upstream INFO: task hung in con_install serial 1 6 2250d 2432d 0/29 closed as dup on 2020/08/16 15:20
linux-4.19 INFO: task hung in con_install 1 1 2409d 2409d 0/1 auto-closed as invalid on 2020/05/29 01:06

Sample crash report:
INFO: task syz.4.1031:9050 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.4.1031      state:D stack:27760 pid:9050  ppid:8692   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 schedule_timeout+0xbd/0x2d0 kernel/time/timer.c:2144
 ___down_common kernel/locking/semaphore.c:229 [inline]
 __down_common+0x30c/0x740 kernel/locking/semaphore.c:250
 down+0x7c/0xd0 kernel/locking/semaphore.c:64
 console_lock+0x141/0x1c0 kernel/printk/printk.c:2629
 con_install+0x94/0x720 drivers/tty/vt/vt.c:3381
 tty_driver_install_tty drivers/tty/tty_io.c:1303 [inline]
 tty_init_dev+0xcf/0x4c0 drivers/tty/tty_io.c:1415
 tty_open_by_driver drivers/tty/tty_io.c:2081 [inline]
 tty_open+0x7d3/0xcb0 drivers/tty/tty_io.c:2128
 chrdev_open+0x585/0x5f0 fs/char_dev.c:414
 do_dentry_open+0x7dd/0x10b0 fs/open.c:882
 do_open fs/namei.c:3677 [inline]
 path_openat+0x2674/0x2f10 fs/namei.c:3834
 do_filp_open+0x1ee/0x420 fs/namei.c:3861
 do_sys_openat2+0x14b/0x4f0 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f4cdd35e98e
RSP: 002b:00007f4cde308b28 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f4cde3096c0 RCX: 00007f4cdd35e98e
RDX: 0000000000000002 RSI: 00007f4cde308c00 RDI: ffffffffffffff9c
RBP: 00007f4cdd435024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f4cdd626038 R14: 00007f4cdd625fa0 R15: 00007fffa7c01d88
 </TASK>
INFO: task syz.9.1037:9081 blocked for more than 143 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.9.1037      state:D stack:27760 pid:9081  ppid:7078   flags:0x00004004
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5246 [inline]
 __schedule+0x107f/0x4030 kernel/sched/core.c:6563
 schedule+0xb9/0x180 kernel/sched/core.c:6639
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6698
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0x548/0xae0 kernel/locking/mutex.c:747
 ptmx_open+0xcc/0x2c0 drivers/tty/pty.c:823
 chrdev_open+0x585/0x5f0 fs/char_dev.c:414
 do_dentry_open+0x7dd/0x10b0 fs/open.c:882
 do_open fs/namei.c:3677 [inline]
 path_openat+0x2674/0x2f10 fs/namei.c:3834
 do_filp_open+0x1ee/0x420 fs/namei.c:3861
 do_sys_openat2+0x14b/0x4f0 fs/open.c:1320
 do_sys_open fs/open.c:1336 [inline]
 __do_sys_openat fs/open.c:1352 [inline]
 __se_sys_openat fs/open.c:1347 [inline]
 __x64_sys_openat+0x135/0x160 fs/open.c:1347
 do_syscall_x64 arch/x86/entry/common.c:46 [inline]
 do_syscall_64+0x4c/0xa0 arch/x86/entry/common.c:76
 entry_SYSCALL_64_after_hwframe+0x68/0xd2
RIP: 0033:0x7f684519e159
RSP: 002b:00007f6845fe9028 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 00007f6845425fa0 RCX: 00007f684519e159
RDX: 0000000000000000 RSI: 0000200000000040 RDI: ffffffffffffff9c
RBP: 00007f6845235024 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 00007f6845426038 R14: 00007f6845425fa0 R15: 00007ffd4bce64c8
 </TASK>

Showing all locks held in the system:
2 locks held by kworker/0:0/7:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8cb2e5b0 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8cb2edd0 (rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x33/0xef0 kernel/rcu/tasks.h:517
2 locks held by kworker/0:1/14:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90000137d00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
1 lock held by khungtaskd/28:
 #0: ffffffff8cb2dc20 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire include/linux/rcupdate.h:350 [inline]
 #0: ffffffff8cb2dc20 (rcu_read_lock){....}-{1:2}, at: rcu_read_lock include/linux/rcupdate.h:791 [inline]
 #0: ffffffff8cb2dc20 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x51/0x290 kernel/locking/lockdep.c:6527
2 locks held by ksmd/33:
 #0: ffffffff8cc19ca8 (ksm_thread_mutex){+.+.}-{3:3}, at: ksm_scan_thread+0x121/0x5ba0 mm/ksm.c:2527
 #1: ffffffff8cbd4ce8 (lock#3){+.+.}-{3:3}, at: __lru_add_drain_all+0x66/0x840 mm/swap.c:865
2 locks held by kworker/0:2/127:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90002e17d00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
2 locks held by getty/4027:
 #0: ffff88802fe1e098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x21/0x70 drivers/tty/tty_ldisc.c:244
 #1: ffffc9000327b2f0 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x41e/0x1360 drivers/tty/n_tty.c:2198
3 locks held by kworker/0:7/4329:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004547d00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #2: ffffffff8cb338f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:323 [inline]
 #2: ffffffff8cb338f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x3c0/0x890 kernel/rcu/tree_exp.h:962
2 locks held by kworker/u4:10/4412:
 #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90004affd00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
3 locks held by kworker/u4:23/4472:
2 locks held by kworker/0:14/5432:
 #0: ffff888017470938 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc90003397d00 ((work_completion)(&pwq->unbound_release_work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
2 locks held by kworker/u4:0/7907:
 #0: ffff888017479138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
 #1: ffffc900039a7d00 ((work_completion)(&sub_info->work)){+.+.}-{0:0}, at: process_one_work+0x7b4/0x1160 kernel/workqueue.c:2267
5 locks held by syz.5.887/8455:
2 locks held by syz.4.1031/9050:
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline]
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xcb0 drivers/tty/tty_io.c:2128
 #1: ffff8880252af1c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_init_dev+0x70/0x4c0 drivers/tty/tty_io.c:1414
1 lock held by syz.9.1037/9081:
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xcc/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.6.1081/9276:
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline]
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xcb0 drivers/tty/tty_io.c:2128
1 lock held by syz.3.1103/9408:
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline]
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xcb0 drivers/tty/tty_io.c:2128
1 lock held by syz.3.1103/9409:
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline]
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xcb0 drivers/tty/tty_io.c:2128
1 lock held by syz.7.1113/9450:
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xcc/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.2.1129/9524:
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xcc/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.8.1198/9913:
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline]
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xcb0 drivers/tty/tty_io.c:2128
1 lock held by syz.4.1210/9974:
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline]
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xcb0 drivers/tty/tty_io.c:2128
1 lock held by syz.5.1221/10013:
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xcc/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.0.1224/10038:
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xcc/0x2c0 drivers/tty/pty.c:823
1 lock held by syz-executor/10049:
 #0: ffffffff8cb338f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: exp_funnel_lock kernel/rcu/tree_exp.h:291 [inline]
 #0: ffffffff8cb338f8 (rcu_state.exp_mutex){+.+.}-{3:3}, at: synchronize_rcu_expedited+0x2ec/0x890 kernel/rcu/tree_exp.h:962
1 lock held by syz.6.1225/10180:
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline]
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xcb0 drivers/tty/tty_io.c:2128
1 lock held by syz.2.1255/10358:
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline]
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xcb0 drivers/tty/tty_io.c:2128
1 lock held by syz.7.1259/10370:
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: ptmx_open+0xcc/0x2c0 drivers/tty/pty.c:823
1 lock held by syz.9.1291/10577:
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2045 [inline]
 #0: ffffffff8d290c68 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x204/0xcb0 drivers/tty/tty_io.c:2128
1 lock held by udevadm/10709:
1 lock held by rm/10714:
2 locks held by modprobe/10715:
1 lock held by modprobe/10716:

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

NMI backtrace for cpu 0
CPU: 0 PID: 28 Comm: khungtaskd Not tainted syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/24/2026
Call Trace:
 <TASK>
 dump_stack_lvl+0x188/0x24e lib/dump_stack.c:106
 nmi_cpu_backtrace+0x3e6/0x460 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1d4/0x450 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:148 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:220 [inline]
 watchdog+0xf0e/0xf50 kernel/hung_task.c:377
 kthread+0x29d/0x330 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:295
 </TASK>

Crashes (5):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2026/09/04 02:05 linux-6.1.y cf82dcca9634 801f0966 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in con_install
2026/09/04 01:58 linux-6.1.y cf82dcca9634 801f0966 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in con_install
2026/08/31 21:24 linux-6.1.y d64a499eea6b 316d9396 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in con_install
2026/08/28 22:53 linux-6.1.y d64a499eea6b 2f52988a .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in con_install
2026/07/31 03:32 linux-6.1.y fb28aa725e05 aaffb173 .config console log report info [disk image] [vmlinux] [kernel image] ci2-linux-6-1-kasan INFO: task hung in con_install
* Struck through repros no longer work on HEAD.