syzbot


INFO: task hung in vhost_net_stop_vq

Status: auto-closed as invalid on 2019/10/12 08:44
Reported-by: syzbot+69e502edc2abadec94e5@syzkaller.appspotmail.com
First crash: 1831d, last: 1831d
Similar bugs (1)
Kernel Title Repro Cause bisect Fix bisect Count Last Reported Patched Status
upstream INFO: task hung in vhost_net_stop_vq kvm net virt C done 136 1829d 1966d 12/26 fixed on 2019/05/27 12:48

Sample crash report:
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
protocol 88fb is buggy, dev hsr_slave_1
protocol 88fb is buggy, dev hsr_slave_0
INFO: task syz-executor.2:7172 blocked for more than 140 seconds.
      Not tainted 4.19.34 #2
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.2  D28216  7172  18849 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:2826 [inline]
 __schedule+0x817/0x1d00 kernel/sched/core.c:3474
 schedule+0x92/0x1c0 kernel/sched/core.c:3518
 schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3576
 __mutex_lock_common kernel/locking/mutex.c:1002 [inline]
 __mutex_lock+0x726/0x1300 kernel/locking/mutex.c:1072
 mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:1087
 vhost_net_stop_vq+0x2d/0x120 drivers/vhost/net.c:1135
 vhost_net_stop drivers/vhost/net.c:1149 [inline]
 vhost_net_release+0x5d/0x190 drivers/vhost/net.c:1181
 __fput+0x2df/0x8b0 fs/file_table.c:278
 ____fput+0x16/0x20 fs/file_table.c:309
 task_work_run+0x14a/0x1c0 kernel/task_work.c:113
 tracehook_notify_resume include/linux/tracehook.h:193 [inline]
 exit_to_usermode_loop+0x273/0x2c0 arch/x86/entry/common.c:166
 prepare_exit_to_usermode arch/x86/entry/common.c:197 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:268 [inline]
 do_syscall_64+0x52d/0x610 arch/x86/entry/common.c:293
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x4129e1
Code: bb c8 00 00 00 ff 15 1e 6e 24 00 85 c0 89 c5 0f 85 7e fc ff ff e9 32 ff ff ff 66 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00 48 <89> 5c 24 d0 4c 89 6c 24 e8 48 89 d3 48 89 6c 24 d8 4c 89 64 24 e0
RSP: 002b:00007ffdc487d500 EFLAGS: 00000293 ORIG_RAX: 0000000000000003
RAX: 0000000000000000 RBX: 0000000000000004 RCX: 00000000004129e1
RDX: 0000001b2dc20000 RSI: 0000000000000000 RDI: 0000000000000003
RBP: 0000000000740b28 R08: 00000000ffc1511e R09: 00000000ffc15122
R10: 00007ffdc487d5d0 R11: 0000000000000293 R12: 0000000000000001
R13: 0000000000307b15 R14: 0000000000307b42 R15: 000000000073bf0c

Showing all locks held in the system:
1 lock held by khungtaskd/1034:
 #0: 00000000c7f66dca (rcu_read_lock){....}, at: debug_show_all_locks+0x5f/0x27e kernel/locking/lockdep.c:4438
1 lock held by rsyslogd/7561:
 #0: 00000000a93f2491 (&f->f_pos_lock){+.+.}, at: __fdget_pos+0xee/0x110 fs/file.c:767
2 locks held by getty/7684:
 #0: 00000000f415711f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
 #1: 00000000b04fe621 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/7685:
 #0: 00000000e60c63da (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
 #1: 00000000ad24612a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/7686:
 #0: 0000000041271f4f (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
 #1: 000000002349e9e4 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/7687:
 #0: 000000004c19d1a3 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
 #1: 00000000993d0c4f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/7688:
 #0: 00000000960ad9d5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
 #1: 00000000c990f588 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/7689:
 #0: 00000000cfa7d7bb (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
 #1: 0000000038d31605 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
2 locks held by getty/7690:
 #0: 000000008a5fc3f7 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x33/0x40 drivers/tty/tty_ldsem.c:363
 #1: 000000000fb8b57e (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x232/0x1b30 drivers/tty/n_tty.c:2154
1 lock held by syz-executor.2/7172:
 #0: 0000000089ab3a04 (&vq->mutex){+.+.}, at: vhost_net_stop_vq+0x2d/0x120 drivers/vhost/net.c:1135
1 lock held by vhost-7211/7218:

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

NMI backtrace for cpu 1
CPU: 1 PID: 1034 Comm: khungtaskd Not tainted 4.19.34 #2
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+0x172/0x1f0 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold+0x63/0xa4 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b0/0x1f8 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:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:202 [inline]
 watchdog+0x9c6/0xec0 kernel/hung_task.c:263
 kthread+0x357/0x430 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 7218 Comm: vhost-7211 Not tainted 4.19.34 #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:iotlb_access_ok+0x416/0x540 drivers/vhost/vhost.c:1221
Code: 38 4c 89 e6 48 8b 7d c8 4d 89 ee e8 a4 3e 39 fc 4d 29 e6 4c 39 65 c8 74 35 e8 76 3d 39 fc 4c 01 75 d0 4c 8b 75 a8 48 8b 5d d0 <4c> 89 f7 48 89 de e8 7f 3e 39 fc 49 39 de 0f 86 31 ff ff ff 4d 89
RSP: 0018:ffff8882126b7aa0 EFLAGS: 00000246
RAX: ffff888089f5a600 RBX: 0000000000000000 RCX: ffffffff8531fa0e
RDX: 0000000000000000 RSI: ffffffff8531f9ca RDI: 0000000000000006
RBP: ffff8882126b7b28 R08: ffff888089f5a600 R09: ffffed10420441a8
R10: ffff8882126b7b60 R11: ffff888210220d3b R12: 0000000000000010
R13: 0000000000000000 R14: 0000000000000010 R15: dffffc0000000000
FS:  0000000000000000(0000) GS:ffff8880ae800000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: ffffffffff600400 CR3: 0000000055fff000 CR4: 00000000001406f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 vq_iotlb_prefetch+0x114/0x230 drivers/vhost/vhost.c:1255
 handle_rx+0x13e/0x1a60 drivers/vhost/net.c:931
 handle_rx_net+0x19/0x20 drivers/vhost/net.c:1073
 vhost_worker+0x2a2/0x4a0 drivers/vhost/vhost.c:362
 kthread+0x357/0x430 kernel/kthread.c:246
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:413

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2019/04/15 08:43 linux-4.19.y 4d552acf3370 505ab413 .config console log report ci2-linux-4-19
* Struck through repros no longer work on HEAD.