syzbot

 sign-in | mailing list | source | docs
🐞 Open [994] ≡ Subsystems 🐞 Fixed [5242] 🐞 Invalid [12515] ⬇ Missing Backports [83] 📈 Kernel Health 📈 Bug Lifetimes 📈 Fuzzing 📈 Crashes 💬 Send us feedback

INFO: task hung in vcs_open

Status: closed as dup on 2020/08/05 10:53
Subsystems: serial
[Documentation on labels]
Reported-by: syzbot+975c6b229a82b59591c0@syzkaller.appspotmail.com
First crash: 1652d, last: 1330d
▶ ▼ Duplicate of
Title Repro Cause bisect Fix bisect Count Last Reported
KASAN: vmalloc-out-of-bounds Write in bitfill_aligned fbdev C 475 1370d 1604d
▶ ▼ Discussions (1)
Title Replies (including bot) Last reply
INFO: task hung in vcs_open 1 (2) 2020/04/24 13:19
▶ ▼ Similar bugs (8)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in vcs_open (5) serial 2 417d 421d 0/26 auto-obsoleted due to no activity on 2023/06/04 04:45
upstream INFO: task hung in vcs_open (3) serial 1 1160d 1160d 0/26 auto-closed as invalid on 2021/05/22 19:06
upstream INFO: task hung in vcs_open (2) serial 1 1310d 1310d 0/26 auto-closed as invalid on 2020/12/23 12:34
linux-4.19 INFO: task hung in vcs_open 11 1266d 1579d 0/1 auto-closed as invalid on 2021/03/07 01:31
upstream INFO: task hung in vcs_open (4) serial 2 571d 633d 0/26 auto-obsoleted due to no activity on 2023/01/02 16:56
linux-4.14 INFO: task hung in vcs_open 3 1424d 1507d 0/1 auto-closed as invalid on 2020/09/30 10:12
upstream INFO: task hung in vcs_open (6) serial 2 190d 254d 0/26 auto-obsoleted due to no activity on 2024/01/17 08:03
linux-4.19 INFO: task hung in vcs_open (2) 1 549d 549d 0/1 auto-obsoleted due to no activity on 2023/02/22 05:12

Sample crash report:
INFO: task syz-executor.3:12397 blocked for more than 143 seconds.
      Not tainted 5.9.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
task:syz-executor.3  state:D stack:26104 pid:12397 ppid:  6873 flags:0x00000004
Call Trace:
 context_switch kernel/sched/core.c:3778 [inline]
 __schedule+0xea9/0x2230 kernel/sched/core.c:4527
 schedule+0xd0/0x2a0 kernel/sched/core.c:4602
 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1855
 __down_common kernel/locking/semaphore.c:220 [inline]
 __down+0x183/0x2a0 kernel/locking/semaphore.c:237
 down+0x57/0x80 kernel/locking/semaphore.c:61
 console_lock+0x25/0x80 kernel/printk/printk.c:2317
 vcs_open+0x62/0xc0 drivers/tty/vt/vc_screen.c:688
 chrdev_open+0x266/0x770 fs/char_dev.c:414
 do_dentry_open+0x4b9/0x11b0 fs/open.c:817
 do_open fs/namei.c:3251 [inline]
 path_openat+0x1b9a/0x2730 fs/namei.c:3368
 do_filp_open+0x17e/0x3c0 fs/namei.c:3395
 do_sys_openat2+0x16d/0x420 fs/open.c:1168
 do_sys_open fs/open.c:1184 [inline]
 __do_sys_openat fs/open.c:1200 [inline]
 __se_sys_openat fs/open.c:1195 [inline]
 __x64_sys_openat+0x13f/0x1f0 fs/open.c:1195
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d5b9
Code: Bad RIP value.
RSP: 002b:00007fad855a0c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000101
RAX: ffffffffffffffda RBX: 0000000000024200 RCX: 000000000045d5b9
RDX: 0000000000000000 RSI: 00000000200000c0 RDI: 00000000ffffff9c
RBP: 000000000118cf88 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffd45c2b3ff R14: 00007fad855a19c0 R15: 000000000118cf4c

Showing all locks held in the system:
1 lock held by khungtaskd/1171:
 #0: ffffffff89bd6a40 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5829
1 lock held by in:imklog/6743:
 #0: ffff8880a90d6670 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:930
2 locks held by agetty/6745:
 #0: ffff88809d927098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267
 #1: ffffc900011b02e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156
5 locks held by syz-executor.2/12384:

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

NMI backtrace for cpu 0
CPU: 0 PID: 1171 Comm: khungtaskd Not tainted 5.9.0-rc3-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+0x198/0x1fd lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline]
 watchdog+0xd7d/0x1000 kernel/hung_task.c:295
 kthread+0x3b5/0x4a0 kernel/kthread.c:292
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:294
Sending NMI from CPU 0 to CPUs 1:
NMI backtrace for cpu 1
CPU: 1 PID: 12384 Comm: syz-executor.2 Not tainted 5.9.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:preempt_count arch/x86/include/asm/preempt.h:26 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:163 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x9/0x60 kernel/kcov.c:197
Code: 5d be 03 00 00 00 e9 96 21 27 02 66 0f 1f 44 00 00 48 8b be b0 01 00 00 e8 b4 ff ff ff 31 c0 c3 90 65 48 8b 14 25 c0 fe 01 00 <65> 8b 05 70 b3 8d 7e a9 00 01 ff 00 48 8b 34 24 74 0f f6 c4 01 74
RSP: 0018:ffffc9000765f090 EFLAGS: 00000282
RAX: 00000000ed9714f0 RBX: 0000000000000050 RCX: ffffffff83cae130
RDX: ffff8880447fc400 RSI: ffff8880447fc400 RDI: 0000000000000005
RBP: 0000000000000050 R08: 0000000000000010 R09: 0000000000000280
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880000a0050
R13: ffff8880000a0000 R14: 0000000000000000 R15: 00000000ed9714f0
FS:  00007f5288306700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00035b000 CR3: 00000000a8749000 CR4: 00000000001506e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 vga16fb_fillrect+0x9a9/0x193b drivers/video/fbdev/vga16fb.c:922
 bit_clear+0x386/0x4d0 drivers/video/fbdev/core/bitblit.c:74
 fbcon_clear+0x519/0x5a0 drivers/video/fbdev/core/fbcon.c:1351
 fbcon_scroll+0x1e20/0x3600 drivers/video/fbdev/core/fbcon.c:1980
 con_scroll+0x5b9/0x6d0 drivers/tty/vt/vt.c:629
 lf+0x26b/0x2c0 drivers/tty/vt/vt.c:1490
 do_con_trol+0x20f/0x51e0 drivers/tty/vt/vt.c:2168
 do_con_write+0xb7f/0x1d70 drivers/tty/vt/vt.c:2906
 con_write+0x22/0xb0 drivers/tty/vt/vt.c:3250
 do_output_char+0x5de/0x850 drivers/tty/n_tty.c:447
 process_output drivers/tty/n_tty.c:514 [inline]
 n_tty_write+0x481/0xf80 drivers/tty/n_tty.c:2345
 do_tty_write drivers/tty/tty_io.c:962 [inline]
 tty_write+0x4d9/0x870 drivers/tty/tty_io.c:1046
 __kernel_write+0x199/0x570 fs/read_write.c:528
 write_pipe_buf+0x153/0x1f0 fs/splice.c:799
 splice_from_pipe_feed fs/splice.c:502 [inline]
 __splice_from_pipe+0x3dc/0x830 fs/splice.c:626
 splice_from_pipe fs/splice.c:661 [inline]
 default_file_splice_write fs/splice.c:811 [inline]
 do_splice_from fs/splice.c:847 [inline]
 direct_splice_actor+0x228/0x2f0 fs/splice.c:1016
 splice_direct_to_actor+0x38c/0x980 fs/splice.c:971
 do_splice_direct+0x1b3/0x280 fs/splice.c:1059
 do_sendfile+0x55f/0xd40 fs/read_write.c:1540
 __do_sys_sendfile64 fs/read_write.c:1601 [inline]
 __se_sys_sendfile64 fs/read_write.c:1587 [inline]
 __x64_sys_sendfile64+0x1cc/0x210 fs/read_write.c:1587
 do_syscall_64+0x2d/0x70 arch/x86/entry/common.c:46
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45d5b9
Code: 5d 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 2b b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f5288305c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000028
RAX: ffffffffffffffda RBX: 0000000000027980 RCX: 000000000045d5b9
RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000003
RBP: 000000000118cf88 R08: 0000000000000000 R09: 0000000000000000
R10: 0800000080004103 R11: 0000000000000246 R12: 000000000118cf4c
R13: 00007ffef18f0e1f R14: 00007f52883069c0 R15: 000000000118cf4c

Crashes (32):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/09/04 05:34 upstream e28f0104343d abf9ba4f .config console log report ci-upstream-kasan-gce-selinux-root
2020/07/26 08:11 upstream 23ee3e4e5bd2 1f7cc1ca .config console log report ci-upstream-kasan-gce-root
2020/07/21 07:52 upstream 4fa640dc5230 d88894e6 .config console log report ci-upstream-kasan-gce-root
2020/07/19 16:56 upstream f932d58abc38 9c812472 .config console log report ci-upstream-kasan-gce-root
2020/07/08 02:35 upstream 7cc2a8ea1048 51095195 .config console log report ci-upstream-kasan-gce
2020/07/07 16:10 upstream 7cc2a8ea1048 51095195 .config console log report ci-upstream-kasan-gce
2020/07/07 06:56 upstream 7cc2a8ea1048 51095195 .config console log report ci-upstream-kasan-gce
2020/07/04 20:47 upstream 7cc2a8ea1048 51095195 .config console log report ci-upstream-kasan-gce
2020/06/18 03:27 upstream 7ae77150d94d b9f3810b .config console log report ci-upstream-kasan-gce
2020/04/18 20:58 upstream 90280eaa88ac 365fba24 .config console log report ci-upstream-kasan-gce-selinux-root
2020/03/07 14:42 upstream 63849c8f4107 2e9971bb .config console log report ci-upstream-kasan-gce-root
2020/02/28 21:28 upstream f8788d86ab28 59b57593 .config console log report ci-upstream-kasan-gce
2020/02/28 15:44 upstream f8788d86ab28 59b57593 .config console log report ci-upstream-kasan-gce-smack-root
2020/02/28 11:11 upstream f8788d86ab28 59b57593 .config console log report ci-upstream-kasan-gce
2020/02/26 17:20 upstream f8788d86ab28 59b57593 .config console log report ci-upstream-kasan-gce
2020/02/25 06:15 upstream f8788d86ab28 59b57593 .config console log report ci-upstream-kasan-gce
2020/01/30 03:49 upstream b3a608222336 5ed23f9a .config console log report ci-upstream-kasan-gce-selinux-root
2020/01/26 16:46 upstream 2821e26f3a0a dd56146d .config console log report ci-upstream-kasan-gce-root
2020/01/25 17:58 upstream d5d359b0ac3f 2e95ab33 .config console log report ci-upstream-kasan-gce-root
2020/01/15 20:58 upstream 51d69817519f f9b69507 .config console log report ci-upstream-kasan-gce
2020/01/15 01:57 upstream e033e7d4a808 fa12bd3c .config console log report ci-upstream-kasan-gce
2019/12/28 09:45 upstream f4b3974602a5 be5c2c81 .config console log report ci-upstream-kasan-gce-selinux-root
2019/12/26 17:33 upstream 46cf053efec6 be5c2c81 .config console log report ci-upstream-kasan-gce-selinux-root
2019/12/26 11:51 upstream 46cf053efec6 be5c2c81 .config console log report ci-upstream-kasan-gce
2019/12/25 22:52 upstream 46cf053efec6 be5c2c81 .config console log report ci-upstream-kasan-gce
2019/10/17 21:24 upstream 283ea345934d 8c88c9c1 .config console log report ci-upstream-kasan-gce-root
2020/07/06 02:00 upstream 7cc2a8ea1048 51095195 .config console log report ci-upstream-kasan-gce-386
2020/07/05 02:33 upstream 7cc2a8ea1048 51095195 .config console log report ci-upstream-kasan-gce-386
2020/03/06 16:09 upstream 63623fd44972 c88c7b75 .config console log report ci-upstream-kasan-gce-386
2020/04/24 08:13 linux-next ac935d227366 2e44d63e .config console log report ci-upstream-linux-next-kasan-gce-root
2020/02/29 21:38 linux-next bdc5461b23ca 59b57593 .config console log report ci-upstream-linux-next-kasan-gce-root
2019/12/15 02:57 linux-next 32b8acf85223 eef6e580 .config console log report ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.