syzbot


INFO: task hung in con_font_op

Status: auto-closed as invalid on 2020/08/30 22:32
Reported-by: syzbot+4133d0ca51bd00722409@syzkaller.appspotmail.com
First crash: 1578d, last: 1449d
Similar bugs (2)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
linux-4.14 INFO: task hung in con_font_op 1 1584d 1584d 0/1 auto-closed as invalid on 2020/04/17 20:41
upstream INFO: task hung in con_font_op serial 2 1423d 1436d 0/26 auto-closed as invalid on 2020/08/26 18:47

Sample crash report:
gfs2: not a GFS2 filesystem
ceph: No mds server is up or the cluster is laggy
ceph: No mds server is up or the cluster is laggy
NOHZ: local_softirq_pending 08
NOHZ: local_softirq_pending 08
INFO: task syz-executor.2:29312 blocked for more than 140 seconds.
      Not tainted 4.19.120-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D28592 29312   6672 0x00000004
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 schedule_timeout+0x896/0xf20 kernel/time/timer.c:1782
 __down_common kernel/locking/semaphore.c:221 [inline]
 __down+0x176/0x2c0 kernel/locking/semaphore.c:238
 down+0x57/0x80 kernel/locking/semaphore.c:62
 console_lock+0x25/0x80 kernel/printk/printk.c:2244
 con_font_set drivers/tty/vt/vt.c:4520 [inline]
 con_font_op+0xc53/0x1130 drivers/tty/vt/vt.c:4589
 vt_ioctl+0xcd0/0x2500 drivers/tty/vt/vt_ioctl.c:928
 tty_ioctl+0x7a1/0x1420 drivers/tty/tty_io.c:2669
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcda/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c829
Code: 08 48 c7 44 24 10 09 00 00 00 e8 02 a1 fa ff 48 8b 44 24 18 48 8b 4c 24 30 48 83 c1 10 48 89 0c 24 48 89 44 24 08 48 c7 44 24 <10> 58 1f 00 00 e8 dd a0 fa ff 48 8b 44 24 18 48 89 44 24 40 48 8b
RSP: 002b:00007f6e1ebb2c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e9280 RCX: 000000000045c829
RDX: 0000000020000000 RSI: 0000000000004b61 RDI: 0000000000000004
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000041d R14: 00000000004c6bd1 R15: 00007f6e1ebb36d4
INFO: task syz-executor.2:29323 blocked for more than 140 seconds.
      Not tainted 4.19.120-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D29344 29323   6672 0x00000004
Call Trace:
 schedule+0x8d/0x1b0 kernel/sched/core.c:3559
 schedule_timeout+0x896/0xf20 kernel/time/timer.c:1782
 __down_common kernel/locking/semaphore.c:221 [inline]
 __down+0x176/0x2c0 kernel/locking/semaphore.c:238
 down+0x57/0x80 kernel/locking/semaphore.c:62
 console_lock+0x25/0x80 kernel/printk/printk.c:2244
 con_font_set drivers/tty/vt/vt.c:4520 [inline]
 con_font_op+0xc53/0x1130 drivers/tty/vt/vt.c:4589
 vt_ioctl+0xcd0/0x2500 drivers/tty/vt/vt_ioctl.c:928
 tty_ioctl+0x7a1/0x1420 drivers/tty/tty_io.c:2669
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcda/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c829
Code: 08 48 c7 44 24 10 09 00 00 00 e8 02 a1 fa ff 48 8b 44 24 18 48 8b 4c 24 30 48 83 c1 10 48 89 0c 24 48 89 44 24 08 48 c7 44 24 <10> 58 1f 00 00 e8 dd a0 fa ff 48 8b 44 24 18 48 89 44 24 40 48 8b
RSP: 002b:00007f6e1eb70c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e9280 RCX: 000000000045c829
RDX: 0000000020000000 RSI: 0000000000004b61 RDI: 0000000000000004
RBP: 000000000078c040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000041d R14: 00000000004c6bd1 R15: 00007f6e1eb716d4

Showing all locks held in the system:
1 lock held by khungtaskd/1080:
 #0: 00000000dbb1fd28 (rcu_read_lock){....}, at: debug_show_all_locks+0x53/0x265 kernel/locking/lockdep.c:4440
1 lock held by in:imklog/6146:
 #0: 00000000f218b39a (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xe3/0x100 fs/file.c:767
1 lock held by syz-executor.4/29234:

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

NMI backtrace for cpu 0
CPU: 0 PID: 1080 Comm: khungtaskd Not tainted 4.19.120-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+0x188/0x20d 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+0x962/0xe40 kernel/hung_task.c:287
 kthread+0x34a/0x420 kernel/kthread.c:246
 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: 29234 Comm: syz-executor.4 Not tainted 4.19.120-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:bitfill_aligned drivers/video/fbdev/core/cfbfillrect.c:43 [inline]
RIP: 0010:bitfill_aligned+0x52/0x200 drivers/video/fbdev/core/cfbfillrect.c:35
Code: 04 44 f0 fd 45 85 e4 74 72 e8 8a 42 f0 fd 49 c7 c6 ff ff ff ff 31 d2 89 ee 43 8d 3c 3c 4c 89 f0 44 89 f9 48 d3 e0 89 7c 24 0c <48> 89 04 24 89 f8 f7 f5 89 d1 49 d3 e6 e8 4c 43 f0 fd 8b 7c 24 0c
RSP: 0018:ffff888044ba7688 EFLAGS: 00000246
RAX: ffffffffffffffff RBX: 0000000000000000 RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000040 RDI: 0000000000000040
RBP: 0000000000000040 R08: ffff8880877ec3c0 R09: 0000000000000040
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000040
R13: ffff8880000a0000 R14: ffffffffffffffff R15: 0000000000000000
FS:  00007f814cf22700(0000) GS:ffff8880ae700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c42e223ed8 CR3: 00000000a6bd3000 CR4: 00000000001406e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 cfb_fillrect+0x418/0x7a0 drivers/video/fbdev/core/cfbfillrect.c:327
 vga16fb_fillrect+0x68f/0x1960 drivers/video/fbdev/vga16fb.c:951
 bit_clear_margins+0x2d5/0x4a0 drivers/video/fbdev/core/bitblit.c:232
 fbcon_clear_margins+0x2d8/0x370 drivers/video/fbdev/core/fbcon.c:1342
 fbcon_do_set_font+0x71d/0xa30 drivers/video/fbdev/core/fbcon.c:2585
 fbcon_set_font+0x733/0x870 drivers/video/fbdev/core/fbcon.c:2677
 con_font_set drivers/tty/vt/vt.c:4524 [inline]
 con_font_op+0xd3e/0x1130 drivers/tty/vt/vt.c:4589
 vt_ioctl+0xcd0/0x2500 drivers/tty/vt/vt_ioctl.c:928
 tty_ioctl+0x7a1/0x1420 drivers/tty/tty_io.c:2669
 vfs_ioctl fs/ioctl.c:46 [inline]
 file_ioctl fs/ioctl.c:501 [inline]
 do_vfs_ioctl+0xcda/0x12e0 fs/ioctl.c:688
 ksys_ioctl+0x9b/0xc0 fs/ioctl.c:705
 __do_sys_ioctl fs/ioctl.c:712 [inline]
 __se_sys_ioctl fs/ioctl.c:710 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:710
 do_syscall_64+0xf9/0x620 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45c829
Code: 0d b7 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 b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f814cf21c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e9280 RCX: 000000000045c829
RDX: 0000000020000000 RSI: 0000000000004b61 RDI: 0000000000000004
RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 000000000000041d R14: 00000000004c6bd1 R15: 00007f814cf226d4

Crashes (3):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/05/02 22:31 linux-4.19.y fdc072324f3c 58da4c35 .config console log report ci2-linux-4-19
2020/01/17 00:40 linux-4.19.y db5b9190ff82 3de7aabb .config console log report ci2-linux-4-19
2019/12/26 01:25 linux-4.19.y 672481c2deff be5c2c81 .config console log report ci2-linux-4-19
* Struck through repros no longer work on HEAD.