syzbot


INFO: task hung in vt_resize (2)

Status: auto-closed as invalid on 2020/09/27 00:31
Reported-by: syzbot+803a3c3ae390ad116d0e@syzkaller.appspotmail.com
First crash: 768d, last: 768d
similar bugs (4):
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.19 INFO: task hung in vt_resize 1 806d 806d 0/1 auto-closed as invalid on 2020/08/19 20:33
upstream INFO: task hung in vt_resize (2) 1 736d 736d 0/22 auto-closed as invalid on 2020/09/29 03:27
upstream INFO: task hung in vt_resize 1 860d 857d 0/22 auto-closed as invalid on 2020/06/27 10:07
linux-4.14 INFO: task hung in vt_resize 1 920d 920d 0/1 auto-closed as invalid on 2020/04/28 10:00

Sample crash report:
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
INFO: task syz-executor.2:27907 blocked for more than 140 seconds.
      Not tainted 4.14.182-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D29680 27907   6361 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2808 [inline]
 __schedule+0x8a6/0x1d70 kernel/sched/core.c:3384
 schedule+0x8d/0x1b0 kernel/sched/core.c:3428
 schedule_timeout+0x86c/0xe50 kernel/time/timer.c:1723
 __down_common kernel/locking/semaphore.c:221 [inline]
 __down+0x17f/0x280 kernel/locking/semaphore.c:238
 down+0x57/0x80 kernel/locking/semaphore.c:62
 console_lock+0x24/0x70 kernel/printk/printk.c:2216
 vt_resize+0x41/0xe0 drivers/tty/vt/vt.c:1007
 tiocswinsz drivers/tty/tty_io.c:2267 [inline]
 tty_ioctl+0x5d3/0x1220 drivers/tty/tty_io.c:2576
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:500 [inline]
 do_vfs_ioctl+0x75a/0xfe0 fs/ioctl.c:684
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x7f/0xb0 fs/ioctl.c:692
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45ca69
RSP: 002b:00007fd5ad7ecc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004ef3c0 RCX: 000000000045ca69
RDX: 0000000020000000 RSI: 0000000000005414 RDI: 0000000000000003
RBP: 000000000078c040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000595 R14: 00000000004c84fc R15: 00007fd5ad7ed6d4

Showing all locks held in the system:
5 locks held by kworker/u4:2/25:
 #0:  ("events_unbound"){+.+.}, at: [<ffffffff813af918>] process_one_work+0x6d8/0x14c0 kernel/workqueue.c:2087
 #1:  ((&buf->work)){+.+.}, at: [<ffffffff813af94e>] process_one_work+0x70e/0x14c0 kernel/workqueue.c:2091
 #2:  (&buf->lock){+.+.}, at: [<ffffffff833c0c75>] flush_to_ldisc+0x35/0x3f0 drivers/tty/tty_buffer.c:499
 #3:  (&tty->ldisc_sem){++++}, at: [<ffffffff833be61b>] tty_ldisc_ref+0x1b/0x80 drivers/tty/tty_ldisc.c:305
 #4:  (&tty->termios_rwsem){++++}, at: [<ffffffff833b7031>] n_tty_receive_buf_common+0x81/0x2490 drivers/tty/n_tty.c:1705
1 lock held by khungtaskd/1025:
 #0:  (tasklist_lock){.+.+}, at: [<ffffffff8146c8d0>] debug_show_all_locks+0x7c/0x21a kernel/locking/lockdep.c:4548
1 lock held by in:imklog/6035:
 #0:  (&f->f_pos_lock){+.+.}, at: [<ffffffff8191ee16>] __fdget_pos+0xa6/0xc0 fs/file.c:769
2 locks held by agetty/6260:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833be562>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff833b9b44>] n_tty_read+0x1e4/0x16e0 drivers/tty/n_tty.c:2156
2 locks held by agetty/6261:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833be562>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff833b9b44>] n_tty_read+0x1e4/0x16e0 drivers/tty/n_tty.c:2156
2 locks held by agetty/6263:
 #0:  (&tty->ldisc_sem){++++}, at: [<ffffffff833be562>] tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:284
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<ffffffff833b9b44>] n_tty_read+0x1e4/0x16e0 drivers/tty/n_tty.c:2156

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

NMI backtrace for cpu 1
CPU: 1 PID: 1025 Comm: khungtaskd Not tainted 4.14.182-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x1b2/0x283 lib/dump_stack.c:58
 nmi_cpu_backtrace.cold+0x57/0x93 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x13a/0x17f lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:140 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:195 [inline]
 watchdog+0x5e2/0xb80 kernel/hung_task.c:274
 kthread+0x30d/0x420 kernel/kthread.c:232
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:404
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 27860 Comm: syz-executor.2 Not tainted 4.14.182-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
task: ffff888052e9a5c0 task.stack: ffff8880352d8000
RIP: 0010:__sanitizer_cov_trace_pc+0x2d/0x50 kernel/kcov.c:85
RSP: 0018:ffff8880352df688 EFLAGS: 00000246
RAX: ffff888052e9a5c0 RBX: ffff8880000a0000 RCX: 0000000000000000
RDX: 0000000000000001 RSI: ffffffff831c0bad RDI: 0000000000000100
RBP: 0000000000000100 R08: 0000000000000100 R09: 0000000000000040
R10: ffffed1014b0a008 R11: ffff8880a5850047 R12: 0000000000000040
R13: 0000000000000000 R14: 0000000000000000 R15: 0000000000000000
FS:  00007fd5ad80e700(0000) GS:ffff8880aec00000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c009e365f0 CR3: 0000000096061000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 bitfill_aligned drivers/video/fbdev/core/cfbfillrect.c:55 [inline]
 bitfill_aligned+0x9d/0x190 drivers/video/fbdev/core/cfbfillrect.c:35
 cfb_fillrect+0x3d5/0x720 drivers/video/fbdev/core/cfbfillrect.c:327
 vga16fb_fillrect+0x61e/0x1880 drivers/video/fbdev/vga16fb.c:951
 bit_clear_margins+0x2a4/0x480 drivers/video/fbdev/core/bitblit.c:232
 fbcon_clear_margins+0x274/0x300 drivers/video/fbdev/core/fbcon.c:1320
 ypan_up_redraw drivers/video/fbdev/core/fbcon.c:1505 [inline]
 fbcon_scroll+0xcd6/0x33c0 drivers/video/fbdev/core/fbcon.c:1883
 con_scroll+0x294/0x310 drivers/tty/vt/vt.c:327
 lf+0x226/0x270 drivers/tty/vt/vt.c:1134
 do_con_write.part.0+0x1223/0x1a20 drivers/tty/vt/vt.c:2407
 do_con_write drivers/tty/vt/vt.c:2218 [inline]
 con_write+0x33/0xc0 drivers/tty/vt/vt.c:2798
 n_tty_write+0x8dd/0xe20 drivers/tty/n_tty.c:2356
 do_tty_write drivers/tty/tty_io.c:959 [inline]
 tty_write+0x3f1/0x6e0 drivers/tty/tty_io.c:1043
 __vfs_write+0xe4/0x630 fs/read_write.c:480
 vfs_write+0x17f/0x4d0 fs/read_write.c:544
 SYSC_write fs/read_write.c:590 [inline]
 SyS_write+0xf2/0x210 fs/read_write.c:582
 do_syscall_64+0x1d5/0x640 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x46/0xbb
RIP: 0033:0x45ca69
RSP: 002b:00007fd5ad80dc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000050c680 RCX: 000000000045ca69
RDX: 0000000000001006 RSI: 0000000020001440 RDI: 0000000000000004
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000ce0 R14: 00000000004cf306 R15: 00007fd5ad80e6d4
Code: 8b 04 25 40 ee 01 00 48 85 c0 74 1a 65 8b 15 ab 4b a7 7e 81 e2 00 01 1f 00 75 0b 8b 90 58 13 00 00 83 fa 01 74 01 c3 48 8b 34 24 <48> 8b 88 60 13 00 00 8b 80 5c 13 00 00 48 8b 11 48 83 c2 01 48 

Crashes (1):
Manager Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Title
ci2-linux-4-14 2020/05/30 00:30 linux-4.14.y 4f68020fef1c bed08304 .config log report