Messages in this thread | | | From | Dmitry Vyukov <> | Date | Mon, 4 Jun 2018 17:22:54 +0200 | Subject | Re: INFO: task hung in ip6gre_exit_batch_net |
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On Mon, Jun 4, 2018 at 5:03 PM, syzbot <syzbot+bf78a74f82c1cf19069e@syzkaller.appspotmail.com> wrote: > Hello, > > syzbot found the following crash on: > > HEAD commit: bc2dbc5420e8 Merge branch 'akpm' (patches from Andrew) > git tree: upstream > console output: https://syzkaller.appspot.com/x/log.txt?x=164e42b7800000 > kernel config: https://syzkaller.appspot.com/x/.config?x=982e2df1b9e60b02 > dashboard link: https://syzkaller.appspot.com/bug?extid=bf78a74f82c1cf19069e > compiler: gcc (GCC) 8.0.1 20180413 (experimental) > > Unfortunately, I don't have any reproducer for this crash yet. > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > Reported-by: syzbot+bf78a74f82c1cf19069e@syzkaller.appspotmail.com
Another hang on rtnl lock:
#syz dup: INFO: task hung in netdev_run_todo
May be related to "unregister_netdevice: waiting for DEV to become free": https://syzkaller.appspot.com/bug?id=1a97a5bd119fd97995f752819fd87840ab9479a9
Any other explanations for massive hangs on rtnl lock for minutes?
> INFO: task kworker/u4:1:22 blocked for more than 120 seconds. > Not tainted 4.17.0-rc6+ #68 > "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message. > kworker/u4:1 D13944 22 2 0x80000000 > Workqueue: netns cleanup_net > Call Trace: > context_switch kernel/sched/core.c:2859 [inline] > __schedule+0x801/0x1e30 kernel/sched/core.c:3501 > schedule+0xef/0x430 kernel/sched/core.c:3545 > schedule_preempt_disabled+0x10/0x20 kernel/sched/core.c:3603 > __mutex_lock_common kernel/locking/mutex.c:833 [inline] > __mutex_lock+0xe38/0x17f0 kernel/locking/mutex.c:893 > mutex_lock_nested+0x16/0x20 kernel/locking/mutex.c:908 > rtnl_lock+0x17/0x20 net/core/rtnetlink.c:74 > ip6gre_exit_batch_net+0xd5/0x7d0 net/ipv6/ip6_gre.c:1585 > ops_exit_list.isra.7+0x105/0x160 net/core/net_namespace.c:155 > cleanup_net+0x51d/0xb20 net/core/net_namespace.c:523 > process_one_work+0xc1e/0x1b50 kernel/workqueue.c:2145 > worker_thread+0x1cc/0x1440 kernel/workqueue.c:2279 > kthread+0x345/0x410 kernel/kthread.c:240 > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 > > Showing all locks held in the system: > 4 locks held by kworker/u4:1/22: > #0: 0000000049a7b590 ((wq_completion)"%s""netns"){+.+.}, at: > __write_once_size include/linux/compiler.h:215 [inline] > #0: 0000000049a7b590 ((wq_completion)"%s""netns"){+.+.}, at: > arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] > #0: 0000000049a7b590 ((wq_completion)"%s""netns"){+.+.}, at: atomic64_set > include/asm-generic/atomic-instrumented.h:40 [inline] > #0: 0000000049a7b590 ((wq_completion)"%s""netns"){+.+.}, at: > atomic_long_set include/asm-generic/atomic-long.h:57 [inline] > #0: 0000000049a7b590 ((wq_completion)"%s""netns"){+.+.}, at: set_work_data > kernel/workqueue.c:617 [inline] > #0: 0000000049a7b590 ((wq_completion)"%s""netns"){+.+.}, at: > set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] > #0: 0000000049a7b590 ((wq_completion)"%s""netns"){+.+.}, at: > process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116 > #1: 0000000030a00b6b (net_cleanup_work){+.+.}, at: > process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120 > #2: 000000007eb35e65 (pernet_ops_rwsem){++++}, at: cleanup_net+0x11a/0xb20 > net/core/net_namespace.c:490 > #3: 000000007eb32c75 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 > net/core/rtnetlink.c:74 > 3 locks held by kworker/1:1/24: > #0: 000000001c9e6580 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: > __write_once_size include/linux/compiler.h:215 [inline] > #0: 000000001c9e6580 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: > arch_atomic64_set arch/x86/include/asm/atomic64_64.h:34 [inline] > #0: 000000001c9e6580 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: > atomic64_set include/asm-generic/atomic-instrumented.h:40 [inline] > #0: 000000001c9e6580 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: > atomic_long_set include/asm-generic/atomic-long.h:57 [inline] > #0: 000000001c9e6580 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: > set_work_data kernel/workqueue.c:617 [inline] > #0: 000000001c9e6580 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: > set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] > #0: 000000001c9e6580 ((wq_completion)"%s"("ipv6_addrconf")){+.+.}, at: > process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116 > #1: 000000009edcfbe7 ((addr_chk_work).work){+.+.}, at: > process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120 > #2: 000000007eb32c75 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 > net/core/rtnetlink.c:74 > 2 locks held by khungtaskd/893: > #0: 000000007eeb621a (rcu_read_lock){....}, at: > check_hung_uninterruptible_tasks kernel/hung_task.c:175 [inline] > #0: 000000007eeb621a (rcu_read_lock){....}, at: watchdog+0x1ff/0xf60 > kernel/hung_task.c:249 > #1: 00000000239f1b5e (tasklist_lock){.+.+}, at: > debug_show_all_locks+0xde/0x34a kernel/locking/lockdep.c:4470 > 2 locks held by getty/4481: > #0: 00000000cc114025 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 > drivers/tty/tty_ldsem.c:365 > #1: 000000006ad1f3fc (&ldata->atomic_read_lock){+.+.}, at: > n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 > 2 locks held by getty/4482: > #0: 00000000226a16cc (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 > drivers/tty/tty_ldsem.c:365 > #1: 000000008cee8cdc (&ldata->atomic_read_lock){+.+.}, at: > n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 > 2 locks held by getty/4483: > #0: 0000000067bd3c39 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 > drivers/tty/tty_ldsem.c:365 > #1: 000000005d8bc81d (&ldata->atomic_read_lock){+.+.}, at: > n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 > 2 locks held by getty/4484: > #0: 00000000f0f8d839 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 > drivers/tty/tty_ldsem.c:365 > #1: 00000000a9d5f091 (&ldata->atomic_read_lock){+.+.}, at: > n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 > 2 locks held by getty/4485: > #0: 000000002c96ee9a (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 > drivers/tty/tty_ldsem.c:365 > #1: 0000000033338ac7 (&ldata->atomic_read_lock){+.+.}, at: > n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 > 2 locks held by getty/4486: > #0: 00000000f6db39b5 (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 > drivers/tty/tty_ldsem.c:365 > #1: 00000000bb7c6099 (&ldata->atomic_read_lock){+.+.}, at: > n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 > 2 locks held by getty/4487: > #0: 000000006be9659d (&tty->ldisc_sem){++++}, at: ldsem_down_read+0x37/0x40 > drivers/tty/tty_ldsem.c:365 > #1: 00000000e2edd3d0 (&ldata->atomic_read_lock){+.+.}, at: > n_tty_read+0x321/0x1cc0 drivers/tty/n_tty.c:2131 > 3 locks held by kworker/1:3/27147: > #0: 00000000c208aa7f ((wq_completion)"events"){+.+.}, at: __write_once_size > include/linux/compiler.h:215 [inline] > #0: 00000000c208aa7f ((wq_completion)"events"){+.+.}, at: arch_atomic64_set > arch/x86/include/asm/atomic64_64.h:34 [inline] > #0: 00000000c208aa7f ((wq_completion)"events"){+.+.}, at: atomic64_set > include/asm-generic/atomic-instrumented.h:40 [inline] > #0: 00000000c208aa7f ((wq_completion)"events"){+.+.}, at: atomic_long_set > include/asm-generic/atomic-long.h:57 [inline] > #0: 00000000c208aa7f ((wq_completion)"events"){+.+.}, at: set_work_data > kernel/workqueue.c:617 [inline] > #0: 00000000c208aa7f ((wq_completion)"events"){+.+.}, at: > set_work_pool_and_clear_pending kernel/workqueue.c:644 [inline] > #0: 00000000c208aa7f ((wq_completion)"events"){+.+.}, at: > process_one_work+0xaef/0x1b50 kernel/workqueue.c:2116 > #1: 00000000fa87e61f (deferred_process_work){+.+.}, at: > process_one_work+0xb46/0x1b50 kernel/workqueue.c:2120 > #2: 000000007eb32c75 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 > net/core/rtnetlink.c:74 > 1 lock held by syz-executor7/29665: > #0: 000000006e20d618 (sk_lock-AF_INET6){+.+.}, at: lock_sock > include/net/sock.h:1469 [inline] > #0: 000000006e20d618 (sk_lock-AF_INET6){+.+.}, at: > tls_sw_sendmsg+0x1b9/0x12e0 net/tls/tls_sw.c:384 > 1 lock held by syz-executor7/29689: > #0: 000000007eb32c75 (rtnl_mutex){+.+.}, at: rtnl_lock+0x17/0x20 > net/core/rtnetlink.c:74 > > ============================================= > > NMI backtrace for cpu 0 > CPU: 0 PID: 893 Comm: khungtaskd Not tainted 4.17.0-rc6+ #68 > 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:240 > ret_from_fork+0x3a/0x50 arch/x86/entry/entry_64.S:412 > Sending NMI from CPU 0 to CPUs 1: > NMI backtrace for cpu 1 skipped: idling at native_safe_halt+0x6/0x10 > arch/x86/include/asm/irqflags.h:54 > > > --- > This bug is generated by a bot. It may contain errors. > See https://goo.gl/tpsmEJ for more information about syzbot. > syzbot engineers can be reached at syzkaller@googlegroups.com. > > syzbot will keep track of this bug report. See: > https://goo.gl/tpsmEJ#bug-status-tracking for how to communicate with > syzbot. > > -- > You received this message because you are subscribed to the Google Groups > "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to syzkaller-bugs+unsubscribe@googlegroups.com. > To view this discussion on the web visit > https://groups.google.com/d/msgid/syzkaller-bugs/0000000000006e4595056dd23c16%40google.com. > For more options, visit https://groups.google.com/d/optout.
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