syzbot

 sign-in | mailing list | source | docs
🐞 Open [712]
🐞 Fixed [297]
🐞 Invalid [838]
≡ Crashes
Kernel Health Bugs/Month Bug Lifetimes Fuzzing
💬 Send us feedback

INFO: task hung in vcs_open

Status: auto-closed as invalid on 2021/03/07 01:31
Reported-by: syzbot+dac06f0da1875a0e0f6b@syzkaller.appspotmail.com
First crash: 2339d, last: 2026d
▶ ▼ Similar bugs (11)
Kernel Title Rank 🛈 Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in vcs_open (5) serial 1 2 1177d 1181d 0/29 auto-obsoleted due to no activity on 2023/06/04 04:45
upstream INFO: task hung in vcs_open (9) kernel 1 11 378d 544d 0/29 auto-obsoleted due to no activity on 2025/08/10 23:55
upstream INFO: task hung in vcs_open (3) serial 1 1 1920d 1920d 0/29 auto-closed as invalid on 2021/05/22 19:06
upstream INFO: task hung in vcs_open serial 1 32 2090d 2223d 0/29 closed as dup on 2020/08/05 10:53
upstream INFO: task hung in vcs_open (2) serial 1 1 2070d 2070d 0/29 auto-closed as invalid on 2020/12/23 12:34
upstream INFO: task hung in vcs_open (7) serial 1 1 800d 800d 0/29 auto-obsoleted due to no activity on 2024/06/15 13:53
upstream INFO: task hung in vcs_open (4) serial 1 2 1331d 1393d 0/29 auto-obsoleted due to no activity on 2023/01/02 16:56
linux-4.14 INFO: task hung in vcs_open 1 3 2184d 2267d 0/1 auto-closed as invalid on 2020/09/30 10:12
upstream INFO: task hung in vcs_open (6) serial 1 2 950d 1014d 0/29 auto-obsoleted due to no activity on 2024/01/17 08:03
linux-4.19 INFO: task hung in vcs_open (2) 1 1 1309d 1309d 0/1 auto-obsoleted due to no activity on 2023/02/22 05:12
upstream INFO: task hung in vcs_open (8) nilfs serial 1 C inconclusive 7 601d 607d 28/29 fixed on 2024/11/12 23:31

Sample crash report:
Bluetooth: hci1: command 0x0406 tx timeout
Bluetooth: hci2: command 0x0406 tx timeout
Bluetooth: hci5: command 0x0406 tx timeout
Bluetooth: hci4: command 0x0406 tx timeout
Bluetooth: hci3: command 0x0406 tx timeout
INFO: task syz-executor.4:11697 blocked for more than 140 seconds.
      Not tainted 4.19.155-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D27680 11697  10769 0x00000004
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:1801
 __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
 vcs_open+0x62/0xc0 drivers/tty/vt/vc_screen.c:660
 chrdev_open+0x266/0x770 fs/char_dev.c:423
 do_dentry_open+0x4aa/0x1160 fs/open.c:796
 do_last fs/namei.c:3421 [inline]
 path_openat+0x793/0x2df0 fs/namei.c:3537
 do_filp_open+0x18c/0x3f0 fs/namei.c:3567
 do_sys_open+0x3b3/0x520 fs/open.c:1085
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4179b1
Code: 75 14 b8 02 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 19 00 00 c3 48 83 ec 08 e8 6a fa ff ff 48 89 04 24 b8 02 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 b3 fa ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007f6646459820 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 00000000004179b1
RDX: 0000000000000000 RSI: 0000000000040000 RDI: 00007f6646459850
RBP: 000000000118bf60 R08: 000000000000000f R09: 0000000000000000
R10: 0000000000000060 R11: 0000000000000293 R12: 000000000118bf2c
R13: 00007fffe3a33a8f R14: 00007f664645a9c0 R15: 000000000118bf2c
INFO: task syz-executor.4:11710 blocked for more than 140 seconds.
      Not tainted 4.19.155-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28064 11710  10769 0x00000004
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:1801
 __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
 vcs_open+0x62/0xc0 drivers/tty/vt/vc_screen.c:660
 chrdev_open+0x266/0x770 fs/char_dev.c:423
 do_dentry_open+0x4aa/0x1160 fs/open.c:796
 do_last fs/namei.c:3421 [inline]
 path_openat+0x793/0x2df0 fs/namei.c:3537
 do_filp_open+0x18c/0x3f0 fs/namei.c:3567
 do_sys_open+0x3b3/0x520 fs/open.c:1085
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4179b1
Code: 75 14 b8 02 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 04 19 00 00 c3 48 83 ec 08 e8 6a fa ff ff 48 89 04 24 b8 02 00 00 00 0f 05 <48> 8b 3c 24 48 89 c2 e8 b3 fa ff ff 48 89 d0 48 83 c4 08 48 3d 01
RSP: 002b:00007f6646438820 EFLAGS: 00000293 ORIG_RAX: 0000000000000002
RAX: ffffffffffffffda RBX: 6666666666666667 RCX: 00000000004179b1
RDX: 0000000000000000 RSI: 0000000000040000 RDI: 00007f6646438850
RBP: 000000000118c008 R08: 000000000000000f R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000293 R12: 000000000118bfd4
R13: 00007fffe3a33a8f R14: 00007f66464399c0 R15: 000000000118bfd4

Showing all locks held in the system:
1 lock held by khungtaskd/1566:
 #0: 0000000022d872bc (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4440
1 lock held by in:imklog/7810:
 #0: 00000000d48bf8c9 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0x26f/0x310 fs/file.c:767
5 locks held by syz-executor.2/11613:

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

NMI backtrace for cpu 0
CPU: 0 PID: 1566 Comm: khungtaskd Not tainted 4.19.155-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: 11613 Comm: syz-executor.2 Not tainted 4.19.155-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:vga16fb_fillrect+0x9cd/0x1940 drivers/video/fbdev/vga16fb.c:922
Code: 24 e8 07 8b bc fd 31 ff 89 de 31 ed e8 6c 8c bc fd 85 db 4d 89 ec 74 22 e8 f0 8a bc fd 45 88 34 24 83 c5 01 89 df 49 83 c4 01 <89> ee e8 cc 8b bc fd 39 eb 75 e3 89 d8 49 01 c5 e8 ce 8a bc fd 31
RSP: 0018:ffff888054c3f0b8 EFLAGS: 00000286
RAX: 0000000000040000 RBX: 0000000000000050 RCX: ffffc9000a04b000
RDX: 0000000000040000 RSI: ffffffff83a843a0 RDI: 0000000000000050
RBP: 000000000000003f R08: 0000000000000010 R09: 0000000000000050
R10: 0000000000000004 R11: 0000000000000000 R12: ffff8880000a003f
R13: ffff8880000a0000 R14: 0000000000000000 R15: 00000000ebe23740
FS:  00007f0b29907700(0000) GS:ffff8880ba100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fa5259f0008 CR3: 0000000055fe4000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 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_write+0x133e/0x1d90 drivers/tty/vt/vt.c:2768
 con_write+0x22/0xb0 drivers/tty/vt/vt.c:3145
 process_output_block drivers/tty/n_tty.c:593 [inline]
 n_tty_write+0x3c0/0xff0 drivers/tty/n_tty.c:2331
 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
 __kernel_write+0x109/0x370 fs/read_write.c:506
 write_pipe_buf+0x153/0x1f0 fs/splice.c:798
 splice_from_pipe_feed fs/splice.c:503 [inline]
 __splice_from_pipe+0x389/0x800 fs/splice.c:627
 splice_from_pipe fs/splice.c:662 [inline]
 default_file_splice_write+0xd8/0x180 fs/splice.c:810
 do_splice_from fs/splice.c:852 [inline]
 direct_splice_actor+0x115/0x160 fs/splice.c:1025
 splice_direct_to_actor+0x33f/0x8d0 fs/splice.c:980
 do_splice_direct+0x1a7/0x270 fs/splice.c:1068
 do_sendfile+0x550/0xc30 fs/read_write.c:1447
 __do_sys_sendfile64 fs/read_write.c:1508 [inline]
 __se_sys_sendfile64+0x147/0x160 fs/read_write.c:1494
 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:00007f0b29906c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 0000000000027f40 RCX: 000000000045deb9
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000003
RBP: 000000000118bf68 R08: 0000000000000000 R09: 0000000000000000
R10: 0800000080004103 R11: 0000000000000246 R12: 000000000118bf2c
R13: 00007fff23be2caf R14: 00007f0b299079c0 R15: 000000000118bf2c

Crashes (11):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/11/07 01:30 linux-4.19.y b94de4d19498 cba33199 .config console log report info ci2-linux-4-19
2020/07/28 03:09 linux-4.19.y 20b3a3dfdf6c cb93dc6a .config console log report ci2-linux-4-19
2020/07/18 22:57 linux-4.19.y 17a87580a885 9c812472 .config console log report ci2-linux-4-19
2020/06/22 08:50 linux-4.19.y b3a99fd385fa eabcced4 .config console log report ci2-linux-4-19
2020/06/04 15:34 linux-4.19.y 4707d8e57273 6720fdef .config console log report ci2-linux-4-19
2020/05/10 10:00 linux-4.19.y 033c4ea49a4b 8742a2b9 .config console log report ci2-linux-4-19
2020/03/16 02:52 linux-4.19.y 569209711609 749688d2 .config console log report ci2-linux-4-19
2020/03/15 20:19 linux-4.19.y 569209711609 749688d2 .config console log report ci2-linux-4-19
2020/01/23 09:34 linux-4.19.y d183c8e2647a 3334d684 .config console log report ci2-linux-4-19
2019/12/30 15:10 linux-4.19.y 672481c2deff af6b8ef8 .config console log report ci2-linux-4-19
2019/12/30 12:05 linux-4.19.y 672481c2deff af6b8ef8 .config console log report ci2-linux-4-19
* Struck through repros no longer work on HEAD.