syzbot


INFO: task hung in drop_sysctl_table

Status: auto-closed as invalid on 2020/10/05 18:28
Subsystems: fs
[Documentation on labels]
First crash: 1384d, last: 1382d

Sample crash report:
INFO: task kworker/u4:6:12123 blocked for more than 143 seconds.
      Not tainted 5.8.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:6    D25016 12123      2 0x00004000
Workqueue: netns cleanup_net
Call Trace:
 context_switch kernel/sched/core.c:3453 [inline]
 __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178
 schedule+0xd0/0x2a0 kernel/sched/core.c:4253
 schedule_timeout+0x1d8/0x250 kernel/time/timer.c:1873
 do_wait_for_common kernel/sched/completion.c:85 [inline]
 __wait_for_common kernel/sched/completion.c:106 [inline]
 wait_for_common kernel/sched/completion.c:117 [inline]
 wait_for_completion+0x163/0x260 kernel/sched/completion.c:138
 start_unregistering fs/proc/proc_sysctl.c:288 [inline]
 drop_sysctl_table+0x41d/0x4e0 fs/proc/proc_sysctl.c:1639
 unregister_sysctl_table fs/proc/proc_sysctl.c:1681 [inline]
 unregister_sysctl_table+0xbd/0x190 fs/proc/proc_sysctl.c:1656
 ip_vs_control_net_cleanup_sysctl net/netfilter/ipvs/ip_vs_ctl.c:4077 [inline]
 ip_vs_control_net_cleanup+0x239/0x4f0 net/netfilter/ipvs/ip_vs_ctl.c:4146
 __ip_vs_cleanup_batch+0x95/0x120 net/netfilter/ipvs/ip_vs_core.c:2421
 ops_exit_list+0x10d/0x160 net/core/net_namespace.c:189
 cleanup_net+0x4ea/0xa00 net/core/net_namespace.c:603
 process_one_work+0x94c/0x1670 kernel/workqueue.c:2269
 worker_thread+0x64c/0x1120 kernel/workqueue.c:2415
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293
INFO: task syz-executor.5:13093 blocked for more than 143 seconds.
      Not tainted 5.8.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5  D28752 13093   7381 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:3453 [inline]
 __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178
 schedule+0xd0/0x2a0 kernel/sched/core.c:4253
 rwsem_down_write_slowpath+0x603/0xc60 kernel/locking/rwsem.c:1235
 __down_write kernel/locking/rwsem.c:1389 [inline]
 down_write+0x137/0x150 kernel/locking/rwsem.c:1532
 register_netdevice_notifier+0x1e/0x260 net/core/dev.c:1808
 bcm_init+0x1a3/0x210 net/can/bcm.c:1451
 can_create+0x27c/0x4d0 net/can/af_can.c:168
 __sock_create+0x3ca/0x740 net/socket.c:1428
 sock_create net/socket.c:1479 [inline]
 __sys_socket+0xef/0x200 net/socket.c:1521
 __do_sys_socket net/socket.c:1530 [inline]
 __se_sys_socket net/socket.c:1528 [inline]
 __x64_sys_socket+0x6f/0xb0 net/socket.c:1528
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cb29
Code: Bad RIP value.
RSP: 002b:00007f028ad71c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 0000000000508420 RCX: 000000000045cb29
RDX: 0000000000000002 RSI: 0000000000000002 RDI: 000000000000001d
RBP: 000000000078bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000bb6 R14: 00000000004ce18b R15: 00007f028ad726d4
INFO: task syz-executor.5:13127 blocked for more than 143 seconds.
      Not tainted 5.8.0-rc3-syzkaller #0
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
syz-executor.5  D28752 13127   7381 0x00000004
Call Trace:
 context_switch kernel/sched/core.c:3453 [inline]
 __schedule+0x8e1/0x1eb0 kernel/sched/core.c:4178
 schedule+0xd0/0x2a0 kernel/sched/core.c:4253
 rwsem_down_write_slowpath+0x603/0xc60 kernel/locking/rwsem.c:1235
 __down_write kernel/locking/rwsem.c:1389 [inline]
 down_write+0x137/0x150 kernel/locking/rwsem.c:1532
 register_netdevice_notifier+0x1e/0x260 net/core/dev.c:1808
 bcm_init+0x1a3/0x210 net/can/bcm.c:1451
 can_create+0x27c/0x4d0 net/can/af_can.c:168
 __sock_create+0x3ca/0x740 net/socket.c:1428
 sock_create net/socket.c:1479 [inline]
 __sys_socket+0xef/0x200 net/socket.c:1521
 __do_sys_socket net/socket.c:1530 [inline]
 __se_sys_socket net/socket.c:1528 [inline]
 __x64_sys_socket+0x6f/0xb0 net/socket.c:1528
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45cb29
Code: Bad RIP value.
RSP: 002b:00007f028ad2fc78 EFLAGS: 00000246 ORIG_RAX: 0000000000000029
RAX: ffffffffffffffda RBX: 0000000000508420 RCX: 000000000045cb29
RDX: 0000000000000002 RSI: 0000000000000002 RDI: 000000000000001d
RBP: 000000000078c040 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 0000000000000bb6 R14: 00000000004ce18b R15: 00007f028ad306d4

Showing all locks held in the system:
1 lock held by khungtaskd/1139:
 #0: ffffffff89bc1180 (rcu_read_lock){....}-{1:2}, at: debug_show_all_locks+0x53/0x260 kernel/locking/lockdep.c:5779
1 lock held by in:imklog/6533:
 #0: ffff8880a6e0bb30 (&f->f_pos_lock){+.+.}-{3:3}, at: __fdget_pos+0xe9/0x100 fs/file.c:826
2 locks held by rs:main Q:Reg/6535:
2 locks held by agetty/6782:
 #0: ffff8880908fa098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267
 #1: ffffc90000ff02e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156
2 locks held by agetty/6784:
 #0: ffff8880a6ee1098 (&tty->ldisc_sem){++++}-{0:0}, at: tty_ldisc_ref_wait+0x22/0x80 drivers/tty/tty_ldisc.c:267
 #1: ffffc90000fe02e8 (&ldata->atomic_read_lock){+.+.}-{3:3}, at: n_tty_read+0x223/0x1a30 drivers/tty/n_tty.c:2156
3 locks held by kworker/u4:6/12123:
 #0: ffff8880a97c9138 ((wq_completion)netns){+.+.}-{0:0}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: ffff8880a97c9138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic64_set include/asm-generic/atomic-instrumented.h:856 [inline]
 #0: ffff8880a97c9138 ((wq_completion)netns){+.+.}-{0:0}, at: atomic_long_set include/asm-generic/atomic-long.h:41 [inline]
 #0: ffff8880a97c9138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_data kernel/workqueue.c:616 [inline]
 #0: ffff8880a97c9138 ((wq_completion)netns){+.+.}-{0:0}, at: set_work_pool_and_clear_pending kernel/workqueue.c:643 [inline]
 #0: ffff8880a97c9138 ((wq_completion)netns){+.+.}-{0:0}, at: process_one_work+0x82b/0x1670 kernel/workqueue.c:2240
 #1: ffffc90001bc7da8 (net_cleanup_work){+.+.}-{0:0}, at: process_one_work+0x85f/0x1670 kernel/workqueue.c:2244
 #2: ffffffff8a7a62f0 (pernet_ops_rwsem){++++}-{3:3}, at: cleanup_net+0x9b/0xa00 net/core/net_namespace.c:565
1 lock held by syz-executor.5/13093:
 #0: ffffffff8a7a62f0 (pernet_ops_rwsem){++++}-{3:3}, at: register_netdevice_notifier+0x1e/0x260 net/core/dev.c:1808
1 lock held by syz-executor.5/13127:
 #0: ffffffff8a7a62f0 (pernet_ops_rwsem){++++}-{3:3}, at: register_netdevice_notifier+0x1e/0x260 net/core/dev.c:1808

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

NMI backtrace for cpu 1
CPU: 1 PID: 1139 Comm: khungtaskd Not tainted 5.8.0-rc3-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+0x18f/0x20d lib/dump_stack.c:118
 nmi_cpu_backtrace.cold+0x70/0xb1 lib/nmi_backtrace.c:101
 nmi_trigger_cpumask_backtrace+0x1b3/0x223 lib/nmi_backtrace.c:62
 trigger_all_cpu_backtrace include/linux/nmi.h:146 [inline]
 check_hung_uninterruptible_tasks kernel/hung_task.c:209 [inline]
 watchdog+0xd7d/0x1000 kernel/hung_task.c:295
 kthread+0x3b5/0x4a0 kernel/kthread.c:291
 ret_from_fork+0x1f/0x30 arch/x86/entry/entry_64.S:293
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0
CPU: 0 PID: 3908 Comm: systemd-journal Not tainted 5.8.0-rc3-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:arch_local_irq_restore+0x34/0x50 arch/x86/include/asm/paravirt.h:766
Code: fb 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 18 48 83 3d a9 e8 5b 08 00 74 0c 48 89 df 57 9d 0f 1f 44 00 00 5b <c3> 0f 0b 48 c7 c7 40 e0 b4 89 e8 2d 15 5a 00 eb da 90 66 2e 0f 1f
RSP: 0018:ffffc900015f7da8 EFLAGS: 00000282
RAX: 1ffffffff1369c08 RBX: 0000000000000000 RCX: ffffffff81bca10f
RDX: dffffc0000000000 RSI: 00000000ffffffff RDI: 0000000000000282
RBP: ffff8880a6d92500 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000000 R12: 0000000000000000
R13: ffff8880a6d92dd0 R14: dffffc0000000000 R15: 0000000000000282
FS:  00007f9b19cf98c0(0000) GS:ffff8880ae600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f9b172e2000 CR3: 00000000a6ca9000 CR4: 00000000001426f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 lock_is_held_type+0xb0/0xe0 kernel/locking/lockdep.c:4998
 lock_is_held include/linux/lockdep.h:425 [inline]
 ___might_sleep+0x22b/0x2f0 kernel/sched/core.c:6865
 dput+0x4d/0xbc0 fs/dcache.c:862
 path_put+0x2d/0x60 fs/namei.c:496
 do_faccessat+0x31c/0x820 fs/open.c:457
 do_syscall_64+0x60/0xe0 arch/x86/entry/common.c:359
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f9b18fb59c7
Code: Bad RIP value.
RSP: 002b:00007fff67d4e468 EFLAGS: 00000246 ORIG_RAX: 0000000000000015
RAX: ffffffffffffffda RBX: 00007fff67d51490 RCX: 00007f9b18fb59c7
RDX: 0000000000000000 RSI: 0000000000000000 RDI: 00005610c66629a3
RBP: 00007fff67d4e5b0 R08: 00005610c66583e5 R09: 0000000000000018
R10: 0000000000000069 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000000000 R14: 00005610c675d8c0 R15: 00007fff67d4eaa0

Crashes (2):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2020/07/07 18:25 upstream 7cc2a8ea1048 51095195 .config console log report ci-upstream-kasan-gce-selinux-root
2020/07/05 17:39 linux-next 9e50b94b3eb0 51095195 .config console log report ci-upstream-linux-next-kasan-gce-root
* Struck through repros no longer work on HEAD.