INFO: task hung in xt_unregister

INFO: task hung in xt_unregister_table
Status: auto-closed as invalid on 2019/08/18 18:50
Reported-by: syzbot+f0ac090339b1aebd6ad5@syzkaller.appspotmail.com
First crash: 1012d, last: 1012d

Sample crash report:
   Free memory is -1148kB above reserved
lowmemorykiller: Killing 'syz-executor.1' (30426) (tgid 30423), adj 1000,
   to free 51360kB on behalf of 'syz-executor.3' (30478) because
   cache 240kB is below limit 6144kB for oom_score_adj 0
   Free memory is -1148kB above reserved
INFO: task kworker/u4:1:24825 blocked for more than 140 seconds.
      Not tainted 4.4.174+ #17
"echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this message.
kworker/u4:1    D ffff88001b387888 25752 24825      2 0x80000000
Workqueue: netns cleanup_net
 ffff88001b387888 ffff880117b94740 97dc67769cf4066a ffff880117b94740
 0000000000000003 ffff880117b95000 ffff8801db61f180 ffff8801db61f1a8
 ffff8801db61e898 ffff8801d441af80 ffff880117b94740 ffffed0003670001
Call Trace:
 [<ffffffff82709b79>] schedule+0x99/0x1d0 kernel/sched/core.c:3355
 [<ffffffff8270a333>] schedule_preempt_disabled+0x13/0x20 kernel/sched/core.c:3388
 [<ffffffff8270c492>] __mutex_lock_common kernel/locking/mutex.c:582 [inline]
 [<ffffffff8270c492>] mutex_lock_nested+0x3c2/0xb80 kernel/locking/mutex.c:621
 [<ffffffff8236e09b>] xt_unregister_table+0x5b/0x250 net/netfilter/x_tables.c:1227
 [<ffffffff8251e2dd>] ipt_unregister_table+0x4d/0x1d0 net/ipv4/netfilter/ip_tables.c:1973
 [<ffffffff82526b7d>] iptable_security_net_exit+0x3d/0x50 net/ipv4/netfilter/iptable_security.c:69
 [<ffffffff82217d90>] ops_exit_list.isra.0+0xb0/0x160 net/core/net_namespace.c:134
 [<ffffffff8221ac16>] cleanup_net+0x3d6/0x860 net/core/net_namespace.c:452
 [<ffffffff81122c25>] process_one_work+0x825/0x1720 kernel/workqueue.c:2064
 [<ffffffff81124004>] worker_thread+0x4e4/0xf50 kernel/workqueue.c:2196
 [<ffffffff811342c3>] kthread+0x273/0x310 kernel/kthread.c:211
 [<ffffffff82718fc5>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537
lowmemorykiller: Killing 'syz-executor.1' (30426) (tgid 30423), adj 1000,
   to free 51360kB on behalf of 'syz-fuzzer' (2095) because
   cache 240kB is below limit 6144kB for oom_score_adj 0
   Free memory is -1148kB above reserved
lowmemorykiller: Killing 'syz-executor.1' (30426) (tgid 30423), adj 1000,
   to free 51360kB on behalf of 'syz-executor.3' (30478) because
   cache 240kB is below limit 6144kB for oom_score_adj 0
   Free memory is -1148kB above reserved
4 locks held by kworker/u4:1/24825:
 #0:  ("%s""netns"){.+.+.+}, at: [<ffffffff81122b0a>] process_one_work+0x70a/0x1720 kernel/workqueue.c:2057
 #1:  (net_cleanup_work){+.+.+.}, at: [<ffffffff81122b42>] process_one_work+0x742/0x1720 kernel/workqueue.c:2061
 #2:  (net_mutex){+.+.+.}, at: [<ffffffff8221a971>] cleanup_net+0x131/0x860 net/core/net_namespace.c:418
 #3:  (&xt[i].mutex){+.+.+.}, at: [<ffffffff8236e09b>] xt_unregister_table+0x5b/0x250 net/netfilter/x_tables.c:1227
Sending NMI to all CPUs:
NMI backtrace for cpu 0
CPU: 0 PID: 1 Comm: init Not tainted 4.4.174+ #17
task: ffff8801da5f0000 task.stack: ffff8801da5f8000
RIP: 0010:[<ffffffff811ffe17>]  [<ffffffff811ffe17>] __lock_acquire+0x867/0x4f50 kernel/locking/lockdep.c:3158
RSP: 0000:ffff8801da5ff140  EFLAGS: 00000006
RAX: 0000000000020000 RBX: 000000000000001d RCX: 0000000000000000
RDX: 0000000000000000 RSI: 0000000000000001 RDI: ffff8801da5f098c
RBP: ffff8801da5ff2c0 R08: 0000000000000004 R09: 1ffff1003b4be12c
R10: ffffffff82836880 R11: 0000000000000000 R12: ffff8801da5f0000
R13: ffff8801da5f0968 R14: 0000000000000000 R15: 0000000000000000
FS:  00007f0eefab77a0(0000) GS:ffff8801db600000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 000000000088a700 CR3: 00000001d776b000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 ffff8801da5f0980 ffff8801da5f08c0 ffff8801da5f0988 0000000000000000
 ffff880100000000 ffffffff83a87e80 ffff8801da5f08c8 1ffff1003b4bfe32
 ffff8801da5f0980 ffff8801da5f08c0 ffff8801da5f0988 ffffffff00000000
Call Trace:
 [<ffffffff81205f6e>] lock_acquire+0x15e/0x450 kernel/locking/lockdep.c:3592
 [<ffffffff813c2826>] rcu_lock_acquire include/linux/rcupdate.h:477 [inline]
 [<ffffffff813c2826>] rcu_read_lock include/linux/rcupdate.h:861 [inline]
 [<ffffffff813c2826>] find_lock_task_mm+0x46/0x280 mm/oom_kill.c:106
 [<ffffffff8211e7cb>] lowmem_scan+0x45b/0xbf0 drivers/staging/android/lowmemorykiller.c:132
 [<ffffffff813ee8e2>] do_shrink_slab mm/vmscan.c:357 [inline]
 [<ffffffff813ee8e2>] shrink_slab.part.0+0x402/0xb30 mm/vmscan.c:455
 [<ffffffff813f742c>] shrink_slab mm/vmscan.c:425 [inline]
 [<ffffffff813f742c>] shrink_zone+0x4bc/0x610 mm/vmscan.c:2448
 [<ffffffff813f7bef>] shrink_zones mm/vmscan.c:2603 [inline]
 [<ffffffff813f7bef>] do_try_to_free_pages mm/vmscan.c:2653 [inline]
 [<ffffffff813f7bef>] try_to_free_pages+0x66f/0x1260 mm/vmscan.c:2861
 [<ffffffff813d09af>] __perform_reclaim mm/page_alloc.c:2915 [inline]
 [<ffffffff813d09af>] __alloc_pages_direct_reclaim mm/page_alloc.c:2936 [inline]
 [<ffffffff813d09af>] __alloc_pages_slowpath mm/page_alloc.c:3201 [inline]
 [<ffffffff813d09af>] __alloc_pages_nodemask+0x8af/0x14b0 mm/page_alloc.c:3313
 [<ffffffff813dc242>] __alloc_pages include/linux/gfp.h:415 [inline]
 [<ffffffff813dc242>] __alloc_pages_node include/linux/gfp.h:428 [inline]
 [<ffffffff813dc242>] alloc_pages_node include/linux/gfp.h:442 [inline]
 [<ffffffff813dc242>] __page_cache_alloc include/linux/pagemap.h:226 [inline]
 [<ffffffff813dc242>] page_cache_alloc_readahead include/linux/pagemap.h:242 [inline]
 [<ffffffff813dc242>] __do_page_cache_readahead+0x222/0x840 mm/readahead.c:184
 [<ffffffff813bf6de>] ra_submit mm/internal.h:55 [inline]
 [<ffffffff813bf6de>] do_sync_mmap_readahead mm/filemap.c:1917 [inline]
 [<ffffffff813bf6de>] filemap_fault+0x74e/0xc10 mm/filemap.c:1994
 [<ffffffff81665ed2>] ext4_filemap_fault+0x72/0xa0 fs/ext4/inode.c:5558
 [<ffffffff8142e82a>] __do_fault+0x1ca/0x350 mm/memory.c:2822
 [<ffffffff8143b9cc>] do_read_fault mm/memory.c:3012 [inline]
 [<ffffffff8143b9cc>] do_fault mm/memory.c:3177 [inline]
 [<ffffffff8143b9cc>] handle_pte_fault mm/memory.c:3346 [inline]
 [<ffffffff8143b9cc>] __handle_mm_fault mm/memory.c:3474 [inline]
 [<ffffffff8143b9cc>] handle_mm_fault+0x1cfc/0x3140 mm/memory.c:3503
 [<ffffffff810aaa4e>] __do_page_fault+0x28e/0x7f0 arch/x86/mm/fault.c:1243
 [<ffffffff810ab008>] do_page_fault+0x28/0x30 arch/x86/mm/fault.c:1306
 [<ffffffff82719e35>] page_fault+0x25/0x30 arch/x86/entry/entry_64.S:1064
Code: 00 00 03 00 0f b7 d2 09 d0 44 89 f2 c1 e2 12 81 e2 00 00 04 00 09 d0 31 d2 85 c9 0f 95 c2 c1 e2 13 09 d0 8b 55 20 c1 e2 14 09 d0 <41> 8b 55 20 81 e2 ff 7f 00 00 09 d0 48 89 fa 41 89 45 20 48 c1 
NMI backtrace for cpu 1
lowmemorykiller: Killing 'syz-executor.1' (30426) (tgid 30423), adj 1000,
   to free 51360kB on behalf of 'syz-executor.3' (30473) because
   cache 240kB is below limit 6144kB for oom_score_adj 0
   Free memory is -1148kB above reserved
CPU: 1 PID: 20 Comm: khungtaskd Not tainted 4.4.174+ #17
task: ffff8801da6f4740 task.stack: ffff8800001d0000
RIP: 0010:[<ffffffff8109b617>]  [<ffffffff8109b617>] _flat_send_IPI_mask arch/x86/kernel/apic/apic_flat_64.c:62 [inline]
RIP: 0010:[<ffffffff8109b617>]  [<ffffffff8109b617>] flat_send_IPI_mask+0xf7/0x1b0 arch/x86/kernel/apic/apic_flat_64.c:69
RSP: 0000:ffff8800001d7c88  EFLAGS: 00000046
RAX: 0000000000000000 RBX: 0000000000000c00 RCX: 0000000000000000
RDX: 0000000000000c00 RSI: 0000000000000000 RDI: ffffffffff5fc300
RBP: ffff8800001d7cb8 R08: 0000000000000018 R09: 0000000000000000
R10: 0000000000000001 R11: 0000000000000001 R12: 0000000000000246
R13: 0000000003000000 R14: ffffffff82e5f2e0 R15: 0000000000000002
FS:  0000000000000000(0000) GS:ffff8801db700000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007f0eef0e71a0 CR3: 00000000b83ca000 CR4: 00000000001606b0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Stack:
 0000000000000001 ffffffff82e5f2e0 ffffffff831a6ac0 fffffbfff0634c34
 000000000001b6c0 0000000000000008 ffff8800001d7cd8 ffffffff81092bee
 0000000000000008 ffffffff82924260 ffff8800001d7d30 ffffffff81ab8252
Call Trace:
 [<ffffffff81092bee>] nmi_raise_cpu_backtrace+0x5e/0x80 arch/x86/kernel/apic/hw_nmi.c:33
 [<ffffffff81ab8252>] nmi_trigger_all_cpu_backtrace.cold+0xa1/0xae lib/nmi_backtrace.c:85
 [<ffffffff81092ca4>] arch_trigger_all_cpu_backtrace+0x14/0x20 arch/x86/kernel/apic/hw_nmi.c:38
 [<ffffffff813b4762>] trigger_all_cpu_backtrace include/linux/nmi.h:44 [inline]
 [<ffffffff813b4762>] check_hung_task kernel/hung_task.c:125 [inline]
 [<ffffffff813b4762>] check_hung_uninterruptible_tasks kernel/hung_task.c:182 [inline]
 [<ffffffff813b4762>] watchdog.cold+0xd3/0xee kernel/hung_task.c:238
 [<ffffffff811342c3>] kthread+0x273/0x310 kernel/kthread.c:211
 [<ffffffff82718fc5>] ret_from_fork+0x55/0x80 arch/x86/entry/entry_64.S:537
Code: 00 c3 5f ff 80 e6 10 75 e1 41 c1 e5 18 44 89 2c 25 10 c3 5f ff 44 89 fa 09 da 80 cf 04 41 83 ff 02 0f 44 d3 89 14 25 00 c3 5f ff <41> f7 c4 00 02 00 00 75 1e 4c 89 e7 57 9d 0f 1f 44 00 00 e8 f1 
lowmemorykiller: Killing 'syz-executor.1' (30426) (tgid 30423), adj 1000,
   to free 51360kB on behalf of 'syz-fuzzer' (2079) because
   cache 216kB is below limit 6144kB for oom_score_adj 0
   Free memory is -1148kB above reserved
lowmemorykiller: Killing 'syz-executor.1' (30426) (tgid 30423), adj 1000,
   to free 51360kB on behalf of 'kswapd0' (28) because
   cache 216kB is below limit 6144kB for oom_score_adj 0
   Free memory is -1148kB above reserved
lowmemorykiller: Killing 'syz-executor.1' (30426) (tgid 30423), adj 1000,
   to free 51360kB on behalf of 'syz-executor.3' (30473) because
   cache 216kB is below limit 6144kB for oom_score_adj 0
   Free memory is -1148kB above reserved
lowmemorykiller: Killing 'syz-executor.1' (30426) (tgid 30423), adj 1000,
   to free 51360kB on behalf of 'syz-fuzzer' (2076) because
   cache 216kB is below limit 6144kB for oom_score_adj 0
   Free memory is -1148kB above reserved
lowmemorykiller: Killing 'syz-executor.1' (30426) (tgid 30423), adj 1000,
   to free 51360kB on behalf of 'rsyslogd' (1929) because
   cache 180kB is below limit 6144kB for oom_score_adj 0
   Free memory is -1148kB above reserved
lowmemorykiller: Killing 'syz-executor.1' (30426) (tgid 30423), adj 1000,
   to free 51360kB on behalf of 'kswapd0' (28) because
   cache 180kB is below limit 6144kB for oom_score_adj 0
   Free memory is -1148kB above reserved
Crashes (1):
Manager	Time	Kernel	Commit	Syzkaller	Config	Log	Report	Syz repro	C repro	VM info	Title
ci-android-44-kasan-gce-386	2019/02/19 18:49	https://android.googlesource.com/kernel/common android-4.4	62872f952d6b	4df543c9	.config	log	report