syzbot


INFO: task hung in do_set_master

Status: fixed on 2018/05/17 10:02
Subsystems: kernel
[Documentation on labels]
Reported-by: syzbot+45cdf2220a9c8a865b40@syzkaller.appspotmail.com
Fix commit: 8236b0ae31c8 bdi: wake up concurrent wb_shutdown() callers.
First crash: 2261d, last: 2261d

Sample crash report:
 notifier_call_chain+0x178/0x380 kernel/notifier.c:93
 __raw_notifier_call_chain kernel/notifier.c:394 [inline]
 raw_notifier_call_chain+0x2d/0x40 kernel/notifier.c:401
 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1734
 call_netdevice_notifiers net/core/dev.c:1752 [inline]
 dev_set_mtu+0x427/0x6b0 net/core/dev.c:7085
 bond_enslave+0x2815/0x5c90 drivers/net/bonding/bond_main.c:1794
INFO: task kworker/0:0:4 blocked for more than 120 seconds.
      Not tainted 4.16.0+ #3
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/0:0     D
23064     4      2 0x80000000
Workqueue: events cgwb_release_workfn
Call Trace:
 context_switch kernel/sched/core.c:2848 [inline]
 __schedule+0x807/0x1e40 kernel/sched/core.c:3490
 do_set_master+0x1c9/0x220 net/core/rtnetlink.c:2238
 do_setlink+0xbd8/0x4310 net/core/rtnetlink.c:2368
 schedule+0xef/0x430 kernel/sched/core.c:3549
 rtnl_setlink+0x2d6/0x430 net/core/rtnetlink.c:2626
 bit_wait+0x18/0x90 kernel/sched/wait_bit.c:197
 __wait_on_bit+0xb3/0x130 kernel/sched/wait_bit.c:48
 rtnetlink_rcv_msg+0x466/0xc10 net/core/rtnetlink.c:4646
 netlink_rcv_skb+0x172/0x440 net/netlink/af_netlink.c:2446
 out_of_line_wait_on_bit+0x204/0x3a0 kernel/sched/wait_bit.c:63
 rtnetlink_rcv+0x1c/0x20 net/core/rtnetlink.c:4664
 netlink_unicast_kernel net/netlink/af_netlink.c:1310 [inline]
 netlink_unicast+0x58b/0x740 net/netlink/af_netlink.c:1336
 netlink_sendmsg+0x9d8/0xf80 net/netlink/af_netlink.c:1899
 sock_sendmsg_nosec net/socket.c:629 [inline]
 sock_sendmsg+0xd5/0x120 net/socket.c:639
 wait_on_bit include/linux/wait_bit.h:76 [inline]
 wb_shutdown+0x370/0x470 mm/backing-dev.c:377
 ___sys_sendmsg+0x805/0x940 net/socket.c:2117
 cgwb_release_workfn+0x87/0x750 mm/backing-dev.c:520
 __sys_sendmsg+0x115/0x270 net/socket.c:2155
 process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145
 SYSC_sendmsg net/socket.c:2164 [inline]
 SyS_sendmsg+0x29/0x30 net/socket.c:2162
 do_syscall_64+0x29e/0x9d0 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
RIP: 0033:0x4552d9
RSP: 002b:00007f594b694c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f594b6956d4 RCX: 00000000004552d9
RDX: 0000000000000000 RSI: 0000000020000080 RDI: 0000000000000013
RBP: 000000000072bea0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000014
R13: 00000000000004f0 R14: 00000000006fa720 R15: 000000000000000a
 worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279
 kthread+0x345/0x410 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411

Showing all locks held in the system:
2 locks held by kworker/0:0/4:
 #0: 00000000e3c5fe44 ((wq_completion)"events"){+.+.}, at: __write_once_size include/linux/compiler.h:215 [inline]
 #0: 00000000e3c5fe44 ((wq_completion)"events"){+.+.}, at: arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline]
 #0: 00000000e3c5fe44 ((wq_completion)"events"){+.+.}, at: atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline]
 #0: 00000000e3c5fe44 ((wq_completion)"events"){+.+.}, at: atomic_long_set include/asm-generic/atomic-long.h:57 [inline]
 #0: 00000000e3c5fe44 ((wq_completion)"events"){+.+.}, at: set_work_data kernel/workqueue.c:617 [inline]
 #0: 00000000e3c5fe44 ((wq_completion)"events"){+.+.}, at: set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline]
 #0: 00000000e3c5fe44 ((wq_completion)"events"){+.+.}, at: process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116
 #1: 000000009e51363c ((work_completion)(&wb->release_work)){+.+.}, at: process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120
2 locks held by khungtaskd/875:
 #0: 0000000016c19978 (rcu_read_lock){....}, at: check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline]
 #0: 0000000016c19978 (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 kernel/hung_task.c:249
 #1: 00000000d1cb7d6a (tasklist_lock){.+.+}, at: debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470
2 locks held by getty/4405:
 #0: 000000009d4570cb (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000b1203dc2 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4406:
 #0: 00000000b9f71bfc (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 000000008537bac8 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4407:
 #0: 00000000cb1fc1fe (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 000000005440b12a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4408:
 #0: 00000000c571cec9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 000000008e57a740 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4409:
 #0: 00000000f7a3c4f9 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 0000000085df4c6f (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4410:
 #0: 00000000bed5b434 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 00000000bc34aa51 (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
2 locks held by getty/4411:
 #0: 000000001196099c (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 drivers/tty/tty_ldsem.c:365
 #1: 0000000098425d7a (&ldata->atomic_read_lock){+.+.}, at: n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131
1 lock held by syz-executor3/27883:
 #0: 00000000d272e5e0 (&vcpu->mutex){+.+.}, at: kvm_vcpu_ioctl+0x1e2/0x12e0 arch/x86/kvm/../../../virt/kvm/kvm_main.c:2542

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

NMI backtrace for cpu 1
CPU: 1 PID: 875 Comm: khungtaskd Not tainted 4.16.0+ #3
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+0x1b9/0x294 lib/dump_stack.c:113
 nmi_cpu_backtrace.cold.4+0x19/0xce lib/nmi_backtrace.c:103
 nmi_trigger_cpumask_backtrace+0x151/0x192 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+0xc10/0xf60 kernel/hung_task.c:249
 kthread+0x345/0x410 kernel/kthread.c:238
 ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:411
Sending NMI from CPU 1 to CPUs 0:
NMI backtrace for cpu 0 skipped: idling at native_safe_halt+0x6/0x10 arch/x86/include/asm/irqflags.h:54

Crashes (1):
Time Kernel Commit Syzkaller Config Log Report Syz repro C repro VM info Assets (help?) Manager Title
2018/04/06 19:29 upstream 38c23685b273 4f1152d4 .config console log report ci-upstream-kasan-gce
* Struck through repros no longer work on HEAD.