syzbot


INFO: task hung in console_callback (2)

Status: auto-closed as invalid on 2021/03/20 18:26
Reported-by: syzbot+94775a9ff51b94a543b0@syzkaller.appspotmail.com
First crash: 1463d, last: 1463d
Similar bugs (6)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in console_callback serial 7 1599d 1767d 0/28 closed as dup on 2020/08/16 15:22
upstream INFO: task hung in console_callback (2) serial 1 992d 992d 0/28 auto-closed as invalid on 2022/06/05 01:15
linux-4.14 INFO: task hung in console_callback 1 1706d 1706d 0/1 auto-closed as invalid on 2020/07/20 15:40
upstream INFO: task hung in console_callback (4) serial 65 419d 426d 0/28 auto-obsoleted due to no activity on 2023/12/09 22:03
upstream INFO: task hung in console_callback (3) serial 11 821d 866d 0/28 auto-obsoleted due to no activity on 2022/11/22 14:53
linux-4.19 INFO: task hung in console_callback 1 1778d 1778d 0/1 auto-closed as invalid on 2020/05/10 04:25

Sample crash report:
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'.
netlink: 24 bytes leftover after parsing attributes in process `syz-executor.2'.
Bluetooth: hci5: command 0x0406 tx timeout
Bluetooth: hci3: command 0x0406 tx timeout
INFO: task kworker/1:1:25 blocked for more than 140 seconds.
      Not tainted 4.19.158-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/1:1     D25680    25      2 0x80000000
Workqueue: events console_callback
Call Trace:
 context_switch kernel/sched/core.c:2828 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3517
 schedule+0x8d/0x1b0 kernel/sched/core.c:3561
 schedule_timeout+0x92d/0xfe0 kernel/time/timer.c:1794
 __down_common kernel/locking/semaphore.c:221 [inline]
 __down+0x183/0x2a0 kernel/locking/semaphore.c:238
 down+0x57/0x80 kernel/locking/semaphore.c:62
 console_lock+0x25/0x80 kernel/printk/printk.c:2275
 console_callback+0x61/0x3f0 drivers/tty/vt/vt.c:2831
 process_one_work+0x864/0x1570 kernel/workqueue.c:2155
 worker_thread+0x64c/0x1130 kernel/workqueue.c:2298
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
INFO: task kworker/u4:8:9634 blocked for more than 140 seconds.
      Not tainted 4.19.158-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:8    D25464  9634      2 0x80000000
Workqueue: events_unbound flush_to_ldisc
Call Trace:
 context_switch kernel/sched/core.c:2828 [inline]
 __schedule+0x887/0x2040 kernel/sched/core.c:3517
 schedule+0x8d/0x1b0 kernel/sched/core.c:3561
 schedule_preempt_disabled+0xf/0x20 kernel/sched/core.c:3619
 __mutex_lock_common kernel/locking/mutex.c:1002 [inline]
 __mutex_lock+0x647/0x1260 kernel/locking/mutex.c:1072
 commit_echoes+0x4c/0x210 drivers/tty/n_tty.c:776
 n_tty_receive_char_fast drivers/tty/n_tty.c:1447 [inline]
 n_tty_receive_buf_fast drivers/tty/n_tty.c:1607 [inline]
 __receive_buf drivers/tty/n_tty.c:1642 [inline]
 n_tty_receive_buf_common+0x1eeb/0x2a90 drivers/tty/n_tty.c:1740
 tty_ldisc_receive_buf+0xa9/0x190 drivers/tty/tty_buffer.c:456
 tty_port_default_receive_buf+0x78/0xa0 drivers/tty/tty_port.c:38
 receive_buf drivers/tty/tty_buffer.c:476 [inline]
 flush_to_ldisc+0x21f/0x390 drivers/tty/tty_buffer.c:528
 process_one_work+0x864/0x1570 kernel/workqueue.c:2155
 worker_thread+0x64c/0x1130 kernel/workqueue.c:2298
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415

Showing all locks held in the system:
2 locks held by kworker/1:1/25:
 #0: 000000004db75fca ((wq_completion)"events"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2126
 #1: 00000000b9c448b1 (console_work){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2130
1 lock held by khungtaskd/1566:
 #0: 00000000e47a41ef (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4440
1 lock held by in:imklog/7806:
 #0: 0000000037de8186 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767
2 locks held by agetty/7804:
 #0: 00000000dd1dabb8 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272
 #1: 0000000046c5c66a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1950 drivers/tty/n_tty.c:2154
2 locks held by agetty/7814:
 #0: 000000006de6bc7d (&tty->ldisc_sem){++++}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:272
 #1: 000000004b51ae9d (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x217/0x1950 drivers/tty/n_tty.c:2154
6 locks held by kworker/u4:8/9634:
 #0: 0000000041cde350 ((wq_completion)"events_unbound"){+.+.}, at: process_one_work+0x767/0x1570 kernel/workqueue.c:2126
 #1: 0000000069ec2694 ((work_completion)(&buf->work)){+.+.}, at: process_one_work+0x79c/0x1570 kernel/workqueue.c:2130
 #2: 0000000067484070 (&buf->lock){+.+.}, at: flush_to_ldisc+0x3e/0x390 drivers/tty/tty_buffer.c:500
 #3: 00000000dd1dabb8 (&tty->ldisc_sem){++++}, at: tty_ldisc_ref+0x1d/0x80 drivers/tty/tty_ldisc.c:293
 #4: 00000000824715dc (&tty->termios_rwsem){++++}, at: n_tty_receive_buf_common+0x84/0x2a90 drivers/tty/n_tty.c:1703
 #5: 0000000090d80b02 (&ldata->output_lock){+.+.}, at: commit_echoes+0x4c/0x210 drivers/tty/n_tty.c:776
5 locks held by syz-executor.3/27889:

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

NMI backtrace for cpu 0
CPU: 0 PID: 1566 Comm: khungtaskd Not tainted 4.19.158-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1fc/0x2fe lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x63/0xa2 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1a6/0x1eb lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:203 [inline]
 watchdog+0x991/0xe60 kernel/hung_task.c:287
 kthread+0x33f/0x460 kernel/kthread.c:259
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:415
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 27889 Comm: syz-executor.3 Not tainted 4.19.158-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__read_once_size include/linux/compiler.h:193 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:69 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x1c/0x50 kernel/kcov.c:101
Code: c6 39 bf 0b 00 00 00 00 e9 39 ec ff ff 90 48 8b 34 24 65 48 8b 04 25 80 df 01 00 65 8b 15 fc 0e 9d 7e 81 e2 00 01 1f 00 75 2b <8b> 90 d8 12 00 00 83 fa 02 75 20 48 8b 88 e0 12 00 00 8b 80 dc 12
RSP: 0018:ffff888048b174f0 EFLAGS: 00000246
RAX: ffff88805d06a440 RBX: 0000000000000050 RCX: ffffffff83a86344
RDX: 0000000000000000 RSI: ffffffff83a86330 RDI: 0000000000000004
RBP: 000000000000000c R08: 0000000000000010 R09: 0000000000000050
R10: 0000000000000004 R11: 0000000000000000 R12: ffff8880000a000c
R13: ffff8880000a0000 R14: 0000000000000000 R15: 00000000edaf985c
FS:  00007fa98db9f700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000056476425c008 CR3: 00000000b520e000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 writeb arch/x86/include/asm/io.h:65 [inline]
 vga16fb_fillrect+0x9c0/0x1940 drivers/video/fbdev/vga16fb.c:923
 bit_clear+0x382/0x4d0 drivers/video/fbdev/core/bitblit.c:74
 fbcon_clear+0x5d6/0x690 drivers/video/fbdev/core/fbcon.c:1258
 fbcon_scroll+0x42e/0x3440 drivers/video/fbdev/core/fbcon.c:1756
 con_scroll+0x5f8/0x720 drivers/tty/vt/vt.c:637
 lf+0x262/0x2b0 drivers/tty/vt/vt.c:1491
 do_con_trol+0x1df/0x5970 drivers/tty/vt/vt.c:2159
 do_con_write+0xbea/0x1d90 drivers/tty/vt/vt.c:2810
 con_write+0x22/0xb0 drivers/tty/vt/vt.c:3145
 do_output_char+0x5de/0x850 drivers/tty/n_tty.c:445
 process_output drivers/tty/n_tty.c:512 [inline]
 n_tty_write+0x46e/0xff0 drivers/tty/n_tty.c:2343
 do_tty_write drivers/tty/tty_io.c:960 [inline]
 tty_write+0x496/0x810 drivers/tty/tty_io.c:1044
 __vfs_write+0xf7/0x770 fs/read_write.c:485
 vfs_write+0x1f3/0x540 fs/read_write.c:549
 ksys_write+0x12b/0x2a0 fs/read_write.c:599
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45deb9
Code: 0d b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fa98db9ec78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000003a6c0 RCX: 000000000045deb9
RDX: 0000000000001006 RSI: 0000000020001440 RDI: 0000000000000006
RBP: 000000000118bf60 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007ffe5b7b373f R14: 00007fa98db9f9c0 R15: 000000000118bf2c

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/11/20 18:25 linux-4.19.y 2c746135a12e 68068804 .config console log report info ci2-linux-4-19
* Struck through repros no longer work on HEAD.