syzbot


INFO: task hung in __wait_rcu_gp

Status: closed as invalid on 2018/02/12 15:43
Subsystems: input
[Documentation on labels]
Reported-by: syzbot+8121ec7e4a91e31276d2@syzkaller.appspotmail.com
First crash: 2569d, last: 2569d

Sample crash report:
INFO: task syz-executor4:8442 blocked for more than 120 seconds.
      Not tainted 4.15.0-rc7-next-20180115+ #97
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor4   D21856  8442   4763 0x80000002
Call Trace:
 context_switch kernel/sched/core.c:2845 [inline]
 __schedule+0x8eb/0x2060 kernel/sched/core.c:3421
 schedule+0xf5/0x430 kernel/sched/core.c:3480
 schedule_timeout+0x1a3/0x230 kernel/time/timer.c:1769
 do_wait_for_common kernel/sched/completion.c:86 [inline]
 __wait_for_common kernel/sched/completion.c:107 [inline]
 wait_for_common kernel/sched/completion.c:118 [inline]
 wait_for_completion+0x415/0x770 kernel/sched/completion.c:139
 __wait_rcu_gp+0x221/0x340 kernel/rcu/update.c:414
 synchronize_sched.part.64+0xac/0x100 kernel/rcu/tree.c:3212
 synchronize_sched+0x76/0xf0 kernel/rcu/tree.c:3213
 synchronize_rcu include/linux/rcupdate.h:94 [inline]
 input_close_device+0xf6/0x130 drivers/input/input.c:663
 mousedev_close_device+0x94/0xb0 drivers/input/mousedev.c:447
 mixdev_close_devices+0xe0/0x120 drivers/input/mousedev.c:497
 mousedev_release+0x8f/0xb0 drivers/input/mousedev.c:531
 __fput+0x327/0x7e0 fs/file_table.c:209
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x199/0x270 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x9bb/0x1ad0 kernel/exit.c:869
 do_group_exit+0x149/0x400 kernel/exit.c:972
 get_signal+0x73f/0x16c0 kernel/signal.c:2337
 do_signal+0x90/0x1eb0 arch/x86/kernel/signal.c:809
 exit_to_usermode_loop+0x258/0x2f0 arch/x86/entry/common.c:161
 prepare_exit_to_usermode arch/x86/entry/common.c:195 [inline]
 syscall_return_slowpath+0x490/0x550 arch/x86/entry/common.c:264
 entry_SYSCALL_64_fastpath+0x9e/0xa0
RIP: 0033:0x452df9
RSP: 002b:00007fc30d193c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000000
RAX: fffffffffffffe00 RBX: 000000000071bea0 RCX: 0000000000452df9
RDX: 0000000000000000 RSI: 00000000204fa000 RDI: 0000000000000013
RBP: 000000000000043f R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f4688
R13: 00000000ffffffff R14: 00007fc30d1946d4 R15: 0000000000000000

Showing all locks held in the system:
2 locks held by khungtaskd/750:
 #0:  (rcu_read_lock){....}, at: [<00000000264bf307>] check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
 #0:  (rcu_read_lock){....}, at: [<00000000264bf307>] watchdog+0x1c5/0xd60 kernel/hung_task.c:249
 #1:  (tasklist_lock){.+.+}, at: [<00000000c7884667>] debug_show_all_locks+0xd3/0x400 kernel/locking/lockdep.c:4464
2 locks held by getty/3642:
 #0:  (&tty->ldisc_sem){++++}, at: [<0000000036a653a0>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<0000000009dc25bd>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3643:
 #0:  (&tty->ldisc_sem){++++}, at: [<0000000036a653a0>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<0000000009dc25bd>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3644:
 #0:  (&tty->ldisc_sem){++++}, at: [<0000000036a653a0>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<0000000009dc25bd>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3645:
 #0:  (&tty->ldisc_sem){++++}, at: [<0000000036a653a0>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<0000000009dc25bd>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3646:
 #0:  (&tty->ldisc_sem){++++}, at: [<0000000036a653a0>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<0000000009dc25bd>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
2 locks held by getty/3647:
 #0:  (&tty->ldisc_sem){++++}, at: [<0000000036a653a0>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<0000000009dc25bd>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131
6 locks held by kworker/u4:5/6342:
 #0:  ((wq_completion)"writeback"){+.+.}, at: [<00000000a760fc82>] process_one_work+0xaaf/0x1af0 kernel/workqueue.c:2084
 #1:  ((work_completion)(&(&wb->dwork)->work)){+.+.}, at: [<00000000b8db681b>] process_one_work+0xb01/0x1af0 kernel/workqueue.c:2088
 #2:  (&type->s_umount_key#42){++++}, at: [<00000000827249fa>] trylock_super+0x20/0x100 fs/super.c:395
 #3:  (&sbi->s_journal_flag_rwsem){.+.+}, at: [<00000000a1e91a17>] do_writepages+0xff/0x170 mm/page-writeback.c:2340
 #4:  (jbd2_handle){++++}, at: [<0000000093b65da9>] start_this_handle+0x488/0x1080 fs/jbd2/transaction.c:385
 #5:  (&ei->i_data_sem){++++}, at: [<00000000c4e6fe26>] ext4_map_blocks+0x377/0x1830 fs/ext4/inode.c:629
3 locks held by syz-executor4/8442:
 #0:  (&mousedev->mutex/1){+.+.}, at: [<000000000d16e6a9>] mixdev_close_devices+0x22/0x120 drivers/input/mousedev.c:489
 #1:  (&mousedev->mutex#2){+.+.}, at: [<00000000b5888b59>] mousedev_close_device+0x20/0xb0 drivers/input/mousedev.c:444
 #2:  (&dev->mutex#2){+.+.}, at: [<0000000052b2421a>] input_close_device+0x48/0x130 drivers/input/input.c:650
1 lock held by syz-executor6/8458:
 #0:  (&lo->lo_ctl_mutex/1){+.+.}, at: [<0000000085236a6a>] lo_ioctl+0x8b/0x1b70 drivers/block/loop.c:1355
2 locks held by getty/8459:
 #0:  (&tty->ldisc_sem){++++}, at: [<0000000036a653a0>] ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1:  (&ldata->atomic_read_lock){+.+.}, at: [<0000000009dc25bd>] n_tty_read+0x2ef/0x1a00 drivers/tty/n_tty.c:2131

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

NMI backtrace for cpu 1
CPU: 1 PID: 750 Comm: khungtaskd Not tainted 4.15.0-rc7-next-20180115+ #97
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+0x194/0x257 lib/dump_stack.c:53
 nmi_cpu_backtrace+0x1d2/0x210 lib/nmi_backtrace.c:103
 nmi_trigger_cpumask_backtrace+0x122/0x180 lib/nmi_backtrace.c:62
 arch_trigger_cpumask_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 trigger_all_cpu_backtrace include/linux/nmi.h:138 [inline]
 check_hung_task kernel/hung_task.c:132 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:190 [inline]
 watchdog+0x90c/0xd60 kernel/hung_task.c:249
 kthread+0x33c/0x400 kernel/kthread.c:238
 ret_from_fork+0x37/0x50 arch/x86/entry/entry_64.S:530
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 8456 Comm: syz-executor6 Not tainted 4.15.0-rc7-next-20180115+ #97
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__sanitizer_cov_trace_pc+0xd/0x50 kernel/kcov.c:94
RSP: 0018:ffff8801d8477a90 EFLAGS: 00000202
RAX: ffff8801bdef2080 RBX: dffffc0000000000 RCX: 0000000000000001
RDX: 0000000000000000 RSI: ffffc900044bf000 RDI: ffff8801d5914f08
RBP: ffff8801d8477a90 R08: 0000000000000000 R09: 1ffff1003b08ef05
R10: ffff8801d84777f0 R11: 0000000000000001 R12: ffff8801d5914dc0
R13: ffff8801c21be4c0 R14: ffff8801cea80180 R15: ffff8801c21be610
FS:  00007f92ad86e700(0000) GS:ffff8801db200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f92ad82c000 CR3: 0000000195695003 CR4: 00000000001606f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 loop_set_fd drivers/block/loop.c:890 [inline]
 lo_ioctl+0x642/0x1b70 drivers/block/loop.c:1358
 __blkdev_driver_ioctl block/ioctl.c:303 [inline]
 blkdev_ioctl+0x1759/0x1e00 block/ioctl.c:601
 block_ioctl+0xde/0x120 fs/block_dev.c:1859
 vfs_ioctl fs/ioctl.c:46 [inline]
 do_vfs_ioctl+0x1b1/0x1520 fs/ioctl.c:686
 SYSC_ioctl fs/ioctl.c:701 [inline]
 SyS_ioctl+0x8f/0xc0 fs/ioctl.c:692
 entry_SYSCALL_64_fastpath+0x29/0xa0
RIP: 0033:0x452df9
RSP: 002b:00007f92ad86dc58 EFLAGS: 00000212 ORIG_RAX: 0000000000000010
RAX: ffffffffffffffda RBX: 00007f92ad86e700 RCX: 0000000000452df9
RDX: 0000000000000013 RSI: 0000000000004c00 RDI: 0000000000000019
RBP: 0000000000000000 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 0000000000000000
R13: 0000000000a2f7ef R14: 00007f92ad86e9c0 R15: 0000000000000000
Code: ff 48 8b bd d0 fe ff ff e8 61 28 38 00 e9 c3 fc ff ff 90 90 90 90 90 90 90 90 90 90 90 90 55 65 48 8b 04 25 c0 ed 01 00 48 89 e5 <65> 8b 15 8c ef 90 7e 81 e2 00 01 1f 00 48 8b 4d 08 75 2b 8b 90 

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/01/16 04:43 linux-next b625c1ff8227 e17f4a5d .config console log report ci-upstream-next-kasan-gce
* Struck through repros no longer work on HEAD.