syzbot


INFO: task hung in tty_set_ldisc

Status: auto-obsoleted due to no activity on 2026/03/15 02:17
Subsystems: serial
[Documentation on labels]
First crash: 128d, last: 128d
✨ AI Jobs (1)
ID Workflow Result Correct Bug Created Started Finished Revision Error
09e8d05c-9a4b-48ba-a006-fa5881be1917 repro 💥 INFO: task hung in tty_set_ldisc 2026/03/08 12:24 2026/03/08 12:24 2026/03/08 12:24 31e9c887f7dc24e04b3ca70d0d54fc34141844b0 failed to run ["git" "fetch" "--force" "--tags" "433dfd5a8a5d80bbf0669b14e9ed908911a52dd6" "05c93f3395ed8b4459ec64f25c2ad41437e56f2b"]: exit status 128

Sample crash report:
INFO: task syz.0.163:7463 blocked for more than 149 seconds.
      Not tainted syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz.0.163       state:D stack:0     pid:7463  tgid:7457  ppid:6552   task_flags:0x400040 flags:0x00000001
Call trace:
 __switch_to+0x418/0x87c arch/arm64/kernel/process.c:741 (T)
 context_switch kernel/sched/core.c:5325 [inline]
 __schedule+0x13b0/0x2864 kernel/sched/core.c:6929
 __schedule_loop kernel/sched/core.c:7011 [inline]
 schedule+0xb4/0x230 kernel/sched/core.c:7026
 schedule_preempt_disabled+0x18/0x2c kernel/sched/core.c:7083
 __mutex_lock_common+0xd04/0x2678 kernel/locking/mutex.c:676
 __mutex_lock kernel/locking/mutex.c:760 [inline]
 mutex_lock_nested+0x2c/0x38 kernel/locking/mutex.c:812
 tty_lock+0x7c/0xd0 drivers/tty/tty_mutex.c:18
 tty_set_ldisc+0x60/0x4dc drivers/tty/tty_ldisc.c:528
 tiocsetd+0xe4/0x128 drivers/tty/tty_io.c:2429
 tty_ioctl+0xb54/0xd8c drivers/tty/tty_io.c:2728
 vfs_ioctl fs/ioctl.c:51 [inline]
 __do_sys_ioctl fs/ioctl.c:597 [inline]
 __se_sys_ioctl fs/ioctl.c:583 [inline]
 __arm64_sys_ioctl+0x14c/0x1c4 fs/ioctl.c:583
 __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]
 invoke_syscall+0x98/0x254 arch/arm64/kernel/syscall.c:49
 el0_svc_common+0xe8/0x23c arch/arm64/kernel/syscall.c:132
 do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151
 el0_svc+0x5c/0x254 arch/arm64/kernel/entry-common.c:724
 el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:743
 el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:596

Showing all locks held in the system:
1 lock held by kthreadd/2:
3 locks held by kworker/0:0/9:
 #0: ffff0000c0029948 ((wq_completion)events){+.+.}-{0:0}, at: process_one_work+0x63c/0x155c kernel/workqueue.c:3237
 #1: ffff800097a57be0 ((work_completion)(&fw_work->work)){+.+.}-{0:0}, at: process_one_work+0x6d4/0x155c kernel/workqueue.c:3237
 #2: ffff800092888228 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:80
2 locks held by kworker/u8:0/12:
3 locks held by kworker/u8:1/15:
2 locks held by kworker/1:0/24:
1 lock held by khungtaskd/32:
 #0: ffff80008f79b760 (rcu_read_lock){....}-{1:3}, at: rcu_lock_acquire+0x4/0x48 include/linux/rcupdate.h:330
1 lock held by khugepaged/37:
3 locks held by kworker/u8:2/41:
6 locks held by kworker/u8:3/42:
 #0: ffff0000c1843148 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x63c/0x155c kernel/workqueue.c:3237
 #1: ffff8000990f7be0 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x6d4/0x155c kernel/workqueue.c:3237
 #2: ffff80009287b3f0 (pernet_ops_rwsem){++++}-{4:4}, at: cleanup_net+0xf4/0x6dc net/core/net_namespace.c:669
 #3: ffff0000d4bec0e8 (&dev->mutex){....}-{4:4}, at: device_lock include/linux/device.h:914 [inline]
 #3: ffff0000d4bec0e8 (&dev->mutex){....}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:108 [inline]
 #3: ffff0000d4bec0e8 (&dev->mutex){....}-{4:4}, at: devlink_pernet_pre_exit+0xe4/0x380 net/devlink/core.c:506
 #4: ffff0000d4bed250 (&devlink->lock_key#4){+.+.}-{4:4}, at: devl_lock net/devlink/core.c:276 [inline]
 #4: ffff0000d4bed250 (&devlink->lock_key#4){+.+.}-{4:4}, at: devl_dev_lock net/devlink/devl_internal.h:109 [inline]
 #4: ffff0000d4bed250 (&devlink->lock_key#4){+.+.}-{4:4}, at: devlink_pernet_pre_exit+0xf0/0x380 net/devlink/core.c:506
 #5: ffff800092888228 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:80
1 lock held by pr/ttyAMA-1/43:
3 locks held by kworker/u8:4/187:
3 locks held by kworker/u8:5/1608:
4 locks held by kworker/0:2/1857:
3 locks held by kworker/u8:6/2020:
3 locks held by kworker/u8:7/2718:
3 locks held by kworker/u8:8/2759:
3 locks held by kworker/u8:9/2808:
3 locks held by kworker/R-ipv6_/4237:
 #0: ffff0000d3a18948 ((wq_completion)ipv6_addrconf){+.+.}-{0:0}, at: process_one_work+0x63c/0x155c kernel/workqueue.c:3237
 #1: ffff80009f9e7bc0 ((work_completion)(&(&net->ipv6.addr_chk_work)->work)){+.+.}-{0:0}, at: process_one_work+0x6d4/0x155c kernel/workqueue.c:3237
 #2: ffff800092888228 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:80
3 locks held by kworker/u8:10/4846:
1 lock held by klogd/6183:
3 locks held by dhcpcd/6249:
2 locks held by getty/6335:
 #0: ffff0000d3cb30a0 (&tty->ldisc_sem){++++}-{0:0}, at: ldsem_down_read+0x3c/0x4c drivers/tty/tty_ldsem.c:340
 #1: ffff80009bb5b2f0 (&ldata->atomic_read_lock){+.+.}-{4:4}, at: n_tty_read+0x34c/0xfa4 drivers/tty/n_tty.c:2222
4 locks held by syz-executor/6539:
4 locks held by kworker/1:2/6553:
3 locks held by kworker/1:3/6554:
1 lock held by syz-executor/6557:
2 locks held by kworker/1:4/6569:
4 locks held by kworker/0:4/6606:
 #0: ffff0000db420d48 ((wq_completion)wg-kex-wg1#4){+.+.}-{0:0}, at: process_one_work+0x63c/0x155c kernel/workqueue.c:3237
 #1: ffff8000a4ba7be0 ((work_completion)(&({ do { const void *__vpp_verify = (typeof((worker) + 0))((void *)0); (void)__vpp_verify; } while (0); ({ unsigned long __ptr; __ptr = (unsigned long) ((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker)))); (typeof((__typeof_unqual__(*((worker))) *)(( unsigned long)((worker))))) (__ptr + (((__per_cpu_offset[(cpu)])))); }); })->work)){+.+.}-{0:0}, at: process_one_work+0x6d4/0x155c kernel/workqueue.c:3237
 #2: ffff0000dbca9348 (&wg->static_identity.lock){++++}-{4:4}, at: wg_noise_handshake_consume_response+0x180/0x954 drivers/net/wireguard/noise.c:742
 #3: ffff0000d57adc60 (&handshake->lock){++++}-{4:4}, at: wg_noise_handshake_consume_response+0x20c/0x954 drivers/net/wireguard/noise.c:753
1 lock held by udevd/6742:
1 lock held by udevd/7194:
 #0: ffff0000c16f4138 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: inode_lock_shared include/linux/fs.h:995 [inline]
 #0: ffff0000c16f4138 (&sb->s_type->i_mutex_key#8){++++}-{4:4}, at: blkdev_read_iter+0x2a0/0x3dc block/fops.c:858
1 lock held by syz.1.158/7452:
 #0: ffff800092888228 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:80
4 locks held by syz.0.163/7459:
1 lock held by syz.0.163/7463:
 #0: ffff0000daef91c0 (&tty->legacy_mutex){+.+.}-{4:4}, at: tty_lock+0x7c/0xd0 drivers/tty/tty_mutex.c:18
4 locks held by segctord/7462:
3 locks held by kworker/u8:11/7465:
3 locks held by kworker/u8:12/7467:
 #0: ffff0000c0032148 ((wq_completion)events_power_efficient){+.+.}-{0:0}, at: process_one_work+0x63c/0x155c kernel/workqueue.c:3237
 #1: ffff80009f5d7be0 ((reg_check_chans).work){+.+.}-{0:0}, at: process_one_work+0x6d4/0x155c kernel/workqueue.c:3237
 #2: ffff800092888228 (rtnl_mutex){+.+.}-{4:4}, at: rtnl_lock+0x20/0x2c net/core/rtnetlink.c:80
4 locks held by kworker/u8:13/7468:
2 locks held by syz-executor/7469:
3 locks held by kworker/u8:14/7470:
2 locks held by kworker/u8:15/7471:
1 lock held by kworker/u8:16/7472:

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Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2025/12/15 02:08 git://git.kernel.org/pub/scm/linux/kernel/git/arm64/linux.git for-kernelci 05c93f3395ed d6526ea3 .config console log report info [disk image] [vmlinux] [kernel image] ci-upstream-gce-arm64 INFO: task hung in tty_set_ldisc
* Struck through repros no longer work on HEAD.