syzbot


INFO: task hung in commit_echoes (3)

Status: auto-obsoleted due to no activity on 2022/11/03 18:56
Subsystems: serial
[Documentation on labels]
First crash: 753d, last: 658d
Similar bugs (5)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in commit_echoes serial 1 2155d 2151d 8/26 fixed on 2018/07/09 18:05
android-49 INFO: task hung in commit_echoes C 44 2147d 1870d 0/3 public: reported C repro on 2019/04/11 08:44
upstream INFO: task hung in commit_echoes (2) serial 3 1338d 1375d 0/26 auto-closed as invalid on 2020/12/23 20:14
upstream INFO: task hung in commit_echoes (4) serial 1 370d 370d 0/26 auto-obsoleted due to no activity on 2023/07/19 08:09
linux-4.19 INFO: task hung in commit_echoes 1 1607d 1607d 0/1 auto-closed as invalid on 2020/04/28 11:37

Sample crash report:
INFO: task kworker/u4:0:19607 blocked for more than 143 seconds.
      Not tainted 5.19.0-syzkaller-02972-g200e340f2196 #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:kworker/u4:0    state:D stack:26536 pid:19607 ppid:     2 flags:0x00004000
Workqueue: events_unbound flush_to_ldisc
Call Trace:
 <TASK>
 context_switch kernel/sched/core.c:5178 [inline]
 __schedule+0xa00/0x4c10 kernel/sched/core.c:6490
 schedule+0xda/0x1b0 kernel/sched/core.c:6566
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:6625
 __mutex_lock_common kernel/locking/mutex.c:679 [inline]
 __mutex_lock+0xa70/0x1350 kernel/locking/mutex.c:747
 commit_echoes+0x4c/0x210 drivers/tty/n_tty.c:761
 n_tty_receive_char+0x3b0/0x5b0 drivers/tty/n_tty.c:1396
 n_tty_receive_buf_standard drivers/tty/n_tty.c:1545 [inline]
 __receive_buf drivers/tty/n_tty.c:1562 [inline]
 n_tty_receive_buf_common+0x1014/0x4770 drivers/tty/n_tty.c:1658
 tty_ldisc_receive_buf+0xa3/0x190 drivers/tty/tty_buffer.c:452
 tty_port_default_receive_buf+0x6e/0xa0 drivers/tty/tty_port.c:39
 receive_buf drivers/tty/tty_buffer.c:472 [inline]
 flush_to_ldisc+0x20a/0x3f0 drivers/tty/tty_buffer.c:522
 process_one_work+0x996/0x1610 kernel/workqueue.c:2289
 worker_thread+0x665/0x1080 kernel/workqueue.c:2436
 kthread+0x2e9/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>

Showing all locks held in the system:
1 lock held by rcu_tasks_kthre/12:
 #0: ffffffff8bd86870 (rcu_tasks.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x26/0xc70 kernel/rcu/tasks.h:507
1 lock held by rcu_tasks_trace/13:
 #0: ffffffff8bd86570 (
rcu_tasks_trace.tasks_gp_mutex){+.+.}-{3:3}, at: rcu_tasks_one_gp+0x26/0xc70 kernel/rcu/tasks.h:507
1 lock held by khungtaskd/28:
 #0: ffffffff8bd873c0 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:6492
1 lock held by aoe_tx0/1238:
2 locks held by getty/3284:
 #0: ffff88814a6fb098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:244
 #1: ffffc90002d162e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0xe50/0x13c0 drivers/tty/n_tty.c:2124
2 locks held by kworker/u4:45/4106:
6 locks held by kworker/u4:0/19607:
 #0: ffff888011869138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff888011869138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: arch_atomic_long_set include/linux/atomic/atomic-long.h:41 [inline]
 #0: ffff888011869138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: atomic_long_set include/linux/atomic/atomic-instrumented.h:1280 [inline]
 #0: ffff888011869138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:636 [inline]
 #0: ffff888011869138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:663 [inline]
 #0: ffff888011869138 ((wq_completion)events_unbound){+.+.}-{0:0}, at: process_one_work+0x87a/0x1610 kernel/workqueue.c:2260
 #1: ffffc9001451fda8 ((work_completion)(&buf->work)){+.+.}-{0:0}, at: process_one_work+0x8ae/0x1610 kernel/workqueue.c:2264
 #2: ffff8880118790b8 (&buf->lock){+.+.}-{3:3}, at: flush_to_ldisc+0x42/0x3f0 drivers/tty/tty_buffer.c:494
 #3: ffff88807beb6098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:264
 #4: ffff88807beb62e8 (&tty->termios_rwsem){++++}-{3:3}, at: n_tty_receive_buf_common+0x84/0x4770 drivers/tty/n_tty.c:1621
 #5: ffffc900137e5378 (&ldata->output_lock){+.+.}-{3:3}, at: commit_echoes+0x4c/0x210 drivers/tty/n_tty.c:761
5 locks held by syz-executor.0/20697:
2 locks held by syz-executor.3/20721:
 #0: ffffffff8c7fb128 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2050 [inline]
 #0: ffffffff8c7fb128 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x552/0xff0 drivers/tty/tty_io.c:2133
 #1: ffff88807bd6c1c0 (&tty->legacy_mutex){+.+.}-{3:3}, at: tty_lock+0xbd/0x120 drivers/tty/tty_mutex.c:20
1 lock held by syz-executor.0/20799:
 #0: ffffffff8c7fb128 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2050 [inline]
 #0: ffffffff8c7fb128 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x552/0xff0 drivers/tty/tty_io.c:2133
1 lock held by syz-executor.3/20811:
 #0: ffffffff8c7fb128 (tty_mutex){+.+.}-{3:3}, at: tty_open_by_driver drivers/tty/tty_io.c:2050 [inline]
 #0: ffffffff8c7fb128 (tty_mutex){+.+.}-{3:3}, at: tty_open+0x552/0xff0 drivers/tty/tty_io.c:2133

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

NMI backtrace for cpu 1
CPU: 1 PID: 28 Comm: khungtaskd Not tainted 5.19.0-syzkaller-02972-g200e340f2196 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Call Trace:
 <TASK>
 __dump_stack lib/dump_stack.c:88 [inline]
 dump_stack_lvl+0xcd/0x134 lib/dump_stack.c:106
 nmi_cpu_backtrace.cold+0x47/0x144 lib/nmi_backtrace.c:111
 nmi_trigger_cpumask_backtrace+0x1e6/0x230 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:212 [inline]
 watchdog+0xc1d/0xf50 kernel/hung_task.c:369
 kthread+0x2e9/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 4106 Comm: kworker/u4:45 Not tainted 5.19.0-syzkaller-02972-g200e340f2196 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/22/2022
Workqueue: events_unbound toggle_allocation_gate
RIP: 0010:bytes_is_nonzero mm/kasan/generic.c:85 [inline]
RIP: 0010:memory_is_nonzero mm/kasan/generic.c:102 [inline]
RIP: 0010:memory_is_poisoned_n mm/kasan/generic.c:128 [inline]
RIP: 0010:memory_is_poisoned mm/kasan/generic.c:159 [inline]
RIP: 0010:check_region_inline mm/kasan/generic.c:180 [inline]
RIP: 0010:kasan_check_range+0xdb/0x180 mm/kasan/generic.c:189
Code: 80 38 00 74 f2 48 89 c2 b8 01 00 00 00 48 85 d2 75 56 5b 5d 41 5c c3 48 85 d2 74 5e 48 01 ea eb 09 48 83 c0 01 48 39 d0 74 50 <80> 38 00 74 f2 eb d4 41 bc 08 00 00 00 48 89 ea 45 29 dc 4d 8d 1c
RSP: 0018:ffffc900071a77d8 EFLAGS: 00000082
RAX: fffffbfff20d1d28 RBX: fffffbfff20d1d29 RCX: ffffffff815e18ae
RDX: fffffbfff20d1d29 RSI: 0000000000000008 RDI: ffffffff9068e940
RBP: fffffbfff20d1d28 R08: 0000000000000000 R09: ffffffff9068e947
R10: fffffbfff20d1d28 R11: 0000000000000001 R12: ffff888079386370
R13: 0000000000000002 R14: 0000000000000006 R15: ffff888079386390
FS:  0000000000000000(0000) GS:ffff8880b9a00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000055636495c000 CR3: 000000000ba8e000 CR4: 00000000003506f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 000000000000003b DR6: 00000000ffff0ff0 DR7: 0000000000000400
Call Trace:
 <TASK>
 instrument_atomic_read include/linux/instrumented.h:71 [inline]
 test_bit include/asm-generic/bitops/instrumented-non-atomic.h:134 [inline]
 hlock_class kernel/locking/lockdep.c:227 [inline]
 mark_lock.part.0+0xee/0x1910 kernel/locking/lockdep.c:4610
 mark_lock kernel/locking/lockdep.c:4596 [inline]
 mark_held_locks+0x9f/0xe0 kernel/locking/lockdep.c:4234
 __trace_hardirqs_on_caller kernel/locking/lockdep.c:4252 [inline]
 lockdep_hardirqs_on_prepare kernel/locking/lockdep.c:4319 [inline]
 lockdep_hardirqs_on_prepare+0x135/0x400 kernel/locking/lockdep.c:4271
 trace_hardirqs_on+0x2d/0x120 kernel/trace/trace_preemptirq.c:49
 __text_poke+0x64e/0x8e0 arch/x86/kernel/alternative.c:1183
 text_poke arch/x86/kernel/alternative.c:1208 [inline]
 text_poke_bp_batch+0x382/0x6c0 arch/x86/kernel/alternative.c:1503
 text_poke_flush arch/x86/kernel/alternative.c:1660 [inline]
 text_poke_flush arch/x86/kernel/alternative.c:1657 [inline]
 text_poke_finish+0x16/0x30 arch/x86/kernel/alternative.c:1667
 arch_jump_label_transform_apply+0x13/0x20 arch/x86/kernel/jump_label.c:146
 jump_label_update+0x32f/0x410 kernel/jump_label.c:801
 static_key_disable_cpuslocked+0x152/0x1b0 kernel/jump_label.c:207
 static_key_disable+0x16/0x20 kernel/jump_label.c:215
 toggle_allocation_gate mm/kfence/core.c:825 [inline]
 toggle_allocation_gate+0x183/0x390 mm/kfence/core.c:803
 process_one_work+0x996/0x1610 kernel/workqueue.c:2289
 worker_thread+0x665/0x1080 kernel/workqueue.c:2436
 kthread+0x2e9/0x3a0 kernel/kthread.c:376
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:306
 </TASK>

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2022/08/05 18:50 upstream 200e340f2196 e853abd9 .config console log report info ci-upstream-kasan-gce INFO: task hung in commit_echoes
2022/05/19 11:43 upstream f993aed406ea 50c53f39 .config console log report info ci-upstream-kasan-gce INFO: task hung in commit_echoes
2022/05/02 16:37 upstream 672c0c517342 2df221f6 .config console log report info ci-upstream-kasan-gce INFO: task hung in commit_echoes
* Struck through repros no longer work on HEAD.