syzbot


INFO: task hung in con_font_op

Status: auto-closed as invalid on 2020/08/26 18:47
Subsystems: serial
[Documentation on labels]
First crash: 1431d, last: 1418d
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 1579d 1579d 0/1 auto-closed as invalid on 2020/04/17 20:41
linux-4.19 INFO: task hung in con_font_op 3 1444d 1573d 0/1 auto-closed as invalid on 2020/08/30 22:32

Sample crash report:
INFO: task syz-executor.2:10224 blocked for more than 143 seconds.
      Not tainted 5.7.0-rc7-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D29400 10224   7301 0x00004004
Call Trace:
 context_switch kernel/sched/core.c:3367 [inline]
 __schedule+0x937/0x1ff0 kernel/sched/core.c:4083
 schedule+0xd0/0x2a0 kernel/sched/core.c:4158
 schedule_timeout+0x55b/0x850 kernel/time/timer.c:1874
 __down_common kernel/locking/semaphore.c:220 [inline]
 __down+0x176/0x2c0 kernel/locking/semaphore.c:237
 down+0x57/0x80 kernel/locking/semaphore.c:61
 console_lock+0x25/0x80 kernel/printk/printk.c:2314
 con_font_copy drivers/tty/vt/vt.c:4617 [inline]
 con_font_op+0x4fb/0x1160 drivers/tty/vt/vt.c:4642
 vt_ioctl+0x1793/0x26b0 drivers/tty/vt/vt_ioctl.c:980
 tty_ioctl+0xedc/0x1440 drivers/tty/tty_io.c:2656
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:771
 __do_sys_ioctl fs/ioctl.c:780 [inline]
 __se_sys_ioctl fs/ioctl.c:778 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:778
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45ca29
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:00007f7b90ba3c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e6ac0 RCX: 000000000045ca29
RDX: 0000000020000000 RSI: 0000000000004b72 RDI: 0000000000000003
RBP: 000000000078c040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000372 R14: 00000000004c6035 R15: 00007f7b90ba46d4
INFO: task syz-executor.4:10214 blocked for more than 143 seconds.
      Not tainted 5.7.0-rc7-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.4  D28104 10214   7396 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:3367 [inline]
 __schedule+0x937/0x1ff0 kernel/sched/core.c:4083
 schedule+0xd0/0x2a0 kernel/sched/core.c:4158
 schedule_timeout+0x55b/0x850 kernel/time/timer.c:1874
 __down_common kernel/locking/semaphore.c:220 [inline]
 __down+0x176/0x2c0 kernel/locking/semaphore.c:237
 down+0x57/0x80 kernel/locking/semaphore.c:61
 console_lock+0x25/0x80 kernel/printk/printk.c:2314
 do_con_write.part.0+0x95/0x1dc0 drivers/tty/vt/vt.c:2596
 do_con_write drivers/tty/vt/vt.c:2593 [inline]
 con_write+0x41/0xe0 drivers/tty/vt/vt.c:3159
 process_output_block drivers/tty/n_tty.c:595 [inline]
 n_tty_write+0x3f0/0xf90 drivers/tty/n_tty.c:2333
 do_tty_write drivers/tty/tty_io.c:962 [inline]
 tty_write+0x495/0x800 drivers/tty/tty_io.c:1046
 do_loop_readv_writev fs/read_write.c:718 [inline]
 do_loop_readv_writev fs/read_write.c:702 [inline]
 do_iter_write fs/read_write.c:1001 [inline]
 do_iter_write+0x486/0x600 fs/read_write.c:980
 vfs_writev+0x1b3/0x2f0 fs/read_write.c:1072
 do_writev+0x139/0x300 fs/read_write.c:1115
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45ca29
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:00007f75c6984c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 000000000050d640 RCX: 000000000045ca29
RDX: 0000000000000001 RSI: 0000000020000000 RDI: 0000000000000005
RBP: 000000000078c040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000d20 R14: 00000000004cb469 R15: 00007f75c69856d4
INFO: task syz-executor.5:10236 blocked for more than 143 seconds.
      Not tainted 5.7.0-rc7-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5  D28104 10236   7658 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:3367 [inline]
 __schedule+0x937/0x1ff0 kernel/sched/core.c:4083
 schedule+0xd0/0x2a0 kernel/sched/core.c:4158
 schedule_timeout+0x55b/0x850 kernel/time/timer.c:1874
 __down_common kernel/locking/semaphore.c:220 [inline]
 __down+0x176/0x2c0 kernel/locking/semaphore.c:237
 down+0x57/0x80 kernel/locking/semaphore.c:61
 console_lock+0x25/0x80 kernel/printk/printk.c:2314
 con_set_cmap+0xa8/0x510 drivers/tty/vt/vt.c:4396
 vt_ioctl+0x1725/0x26b0 drivers/tty/vt/vt_ioctl.c:936
 tty_ioctl+0xedc/0x1440 drivers/tty/tty_io.c:2656
 vfs_ioctl fs/ioctl.c:47 [inline]
 ksys_ioctl+0x11a/0x180 fs/ioctl.c:771
 __do_sys_ioctl fs/ioctl.c:780 [inline]
 __se_sys_ioctl fs/ioctl.c:778 [inline]
 __x64_sys_ioctl+0x6f/0xb0 fs/ioctl.c:778
 do_syscall_64+0xf6/0x7d0 arch/x86/entry/common.c:295
 entry_SYSCALL_64_after_hwframe+0x49/0xb3
RIP: 0033:0x45ca29
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:00007fdb3c575c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00000000004e6ac0 RCX: 000000000045ca29
RDX: 0000000020000400 RSI: 0000000000004b71 RDI: 0000000000000003
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000372 R14: 00000000004c6035 R15: 00007fdb3c5766d4

Showing all locks held in the system:
1 lock held by khungtaskd/1135:
 #0: ffffffff899bea80 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5754
1 lock held by in:imklog/6737:
 #0: ffff88809f35ad70 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826
4 locks held by kworker/u4:14/30873:
2 locks held by syz-executor.0/10203:
4 locks held by syz-executor.4/10214:
 #0: ffff8880a3196098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267
 #1: ffff8880a3196130 (&tty->atomic_write_lock){+.+.}-{3:3}, at: tty_write_lock+0x1e/0x80 drivers/tty/tty_io.c:888
 #2: ffff8880a31962e8 (&tty->termios_rwsem){++++}-{3:3}, at: n_tty_write+0x1b2/0xf90 drivers/tty/n_tty.c:2316
 #3: ffffc90007c5d378 (&ldata->output_lock){+.+.}-{3:3}, at: process_output_block drivers/tty/n_tty.c:550 [inline]
 #3: ffffc90007c5d378 (&ldata->output_lock){+.+.}-{3:3}, at: n_tty_write+0x50c/0xf90 drivers/tty/n_tty.c:2333

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

NMI backtrace for cpu 1
CPU: 1 PID: 1135 Comm: khungtaskd Not tainted 5.7.0-rc7-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+0x70/0xb1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x231/0x27e lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:205 [inline]
 watchdog+0xa8c/0x1010 kernel/hung_task.c:289
 kthread+0x388/0x470 kernel/kthread.c:268
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 30873 Comm: kworker/u4:14 Not tainted 5.7.0-rc7-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: krdsd rds_connect_worker
RIP: 0010:test_bit include/asm-generic/bitops/instrumented-non-atomic.h:110 [inline]
RIP: 0010:hlock_class kernel/locking/lockdep.c:179 [inline]
RIP: 0010:mark_lock+0x11a/0xf10 kernel/locking/lockdep.c:3912
Code: e8 03 0f b6 04 10 84 c0 74 08 3c 03 0f 8e e3 0b 00 00 0f b7 55 20 66 81 e2 ff 1f 0f b7 d2 be 08 00 00 00 48 89 d0 48 89 14 24 <48> c1 f8 06 48 8d 3c c5 60 f9 2e 8c e8 55 d4 57 00 48 8b 14 24 48
RSP: 0018:ffffc9000457f848 EFLAGS: 00000002
RAX: 00000000000003d9 RBX: 1ffff920008aff0f RCX: 1ffffffff1863dcb
RDX: 00000000000003d9 RSI: 0000000000000008 RDI: ffff88804b550140
RBP: ffff88804b550aa8 R08: 0000000000000001 R09: fffffbfff185df3d
R10: ffffffff8c2ef9e7 R11: fffffbfff185df3c R12: 0000000000000002
R13: ffff88804b550140 R14: ffff88804b550a08 R15: ffff88804b550ac8
FS:  0000000000000000(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000c00d4d78e0 CR3: 000000020e602000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 mark_held_locks+0x9f/0xe0 kernel/locking/lockdep.c:3628
 __trace_hardirqs_on_caller kernel/locking/lockdep.c:3649 [inline]
 lockdep_hardirqs_on+0x196/0x620 kernel/locking/lockdep.c:3702
 __local_bh_enable_ip+0x159/0x270 kernel/softirq.c:194
 sock_i_uid+0x8e/0xb0 net/core/sock.c:2092
 inet_csk_bind_conflict+0x86/0x590 net/ipv4/inet_connection_sock.c:140
 inet_csk_find_open_port net/ipv4/inet_connection_sock.c:233 [inline]
 inet_csk_get_port+0xd41/0x2520 net/ipv4/inet_connection_sock.c:317
 __inet_bind+0x5b2/0xbd0 net/ipv4/af_inet.c:524
 inet_bind+0xf3/0x160 net/ipv4/af_inet.c:453
 rds_tcp_conn_path_connect+0x536/0x880 net/rds/tcp_connect.c:144
 rds_connect_worker+0x1a5/0x2c0 net/rds/threads.c:176
 process_one_work+0x965/0x16a0 kernel/workqueue.c:2268
 worker_thread+0x96/0xe20 kernel/workqueue.c:2414
 kthread+0x388/0x470 kernel/kthread.c:268
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:351

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/05/28 18:45 upstream b0c3ba31be3e 0d951763 .config console log report ci-upstream-kasan-gce-selinux-root
2020/05/15 09:24 linux-next ac935d227366 2d572622 .config console log report ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.