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BUG: KASAN: use-after-free in inet_frag_destroy_rcu+0xd9/0xe0 net/ipv4/inet_fragment.c:201
Read of size 8 at addr ffff8880a0737d58 by task kworker/u4:3/406

CPU: 1 PID: 406 Comm: kworker/u4:3 Not tainted 5.2.0-rc2-next-20190529 #2
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Workqueue: netns cleanup_net
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x172/0x1f0 lib/dump_stack.c:113
 print_address_description.cold+0x7c/0x20d mm/kasan/report.c:188
 __kasan_report.cold+0x1b/0x40 mm/kasan/report.c:317
 kasan_report+0x12/0x20 mm/kasan/common.c:614
 __asan_report_load8_noabort+0x14/0x20 mm/kasan/generic_report.c:132
 inet_frag_destroy_rcu+0xd9/0xe0 net/ipv4/inet_fragment.c:201
 __rcu_reclaim kernel/rcu/rcu.h:222 [inline]
 rcu_do_batch kernel/rcu/tree.c:2092 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2310 [inline]
 rcu_core+0xba5/0x1500 kernel/rcu/tree.c:2291
 __do_softirq+0x25c/0x94c kernel/softirq.c:293
 invoke_softirq kernel/softirq.c:374 [inline]
 irq_exit+0x180/0x1d0 kernel/softirq.c:414
 exiting_irq arch/x86/include/asm/apic.h:536 [inline]
 smp_apic_timer_interrupt+0x13b/0x550 arch/x86/kernel/apic/apic.c:1068
 apic_timer_interrupt+0xf/0x20 arch/x86/entry/entry_64.S:806
 </IRQ>
RIP: 0010:__raw_spin_unlock_irq include/linux/spinlock_api_smp.h:169 [inline]
RIP: 0010:_raw_spin_unlock_irq+0x54/0x90 kernel/locking/spinlock.c:199
Code: c0 80 74 d2 88 48 ba 00 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 75 33 48 83 3d 95 07 b2 01 00 74 20 fb 66 0f 1f 44 00 00 <bf> 01 00 00 00 e8 d2 3e 2d fa 65 8b 05 83 90 e1 78 85 c0 74 06 41
RSP: 0018:ffff8880a8e17830 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff13
RAX: 1ffffffff11a4e90 RBX: ffff8880a8e0a080 RCX: 1ffff110151c152f
RDX: dffffc0000000000 RSI: ffff8880a8e0a958 RDI: ffff8880a8e0a904
RBP: ffff8880a8e17838 R08: ffff8880a8e0a080 R09: ffff8880a8e0a978
R10: 0000000000000000 R11: 0000000000000000 R12: ffff8880ae935080
R13: ffff8880516b8440 R14: 0000000000000000 R15: 0000000000000002
 finish_lock_switch kernel/sched/core.c:2568 [inline]
 finish_task_switch+0x146/0x730 kernel/sched/core.c:2668
 context_switch kernel/sched/core.c:2821 [inline]
 __schedule+0x7d3/0x1560 kernel/sched/core.c:3445
 preempt_schedule_irq+0xb5/0x140 kernel/sched/core.c:3693
 retint_kernel+0x1b/0x2b
RIP: 0010:should_resched arch/x86/include/asm/preempt.h:102 [inline]
RIP: 0010:__local_bh_enable_ip+0x18e/0x270 kernel/softirq.c:197
Code: 00 00 00 00 fc ff df 48 c1 e8 03 80 3c 10 00 0f 85 df 00 00 00 48 83 3d ef d1 8d 07 00 0f 84 8f 00 00 00 fb 66 0f 1f 44 00 00 <65> 8b 05 e3 5a bd 7e 85 c0 74 7f 5b 41 5c 41 5d 5d c3 80 3d 25 75
RSP: 0018:ffff8880a8e17a40 EFLAGS: 00000286 ORIG_RAX: ffffffffffffff02
RAX: 1ffffffff11a4e90 RBX: 0000000000000200 RCX: 1ffff110151c152f
RDX: dffffc0000000000 RSI: ffff8880a8e0a958 RDI: ffff8880a8e0a904
RBP: ffff8880a8e17a58 R08: ffff8880a8e0a080 R09: ffff8880a8e0a978
R10: 0000000000000000 R11: 0000000000000000 R12: ffffffff85baa791
R13: ffff8880a8e0a080 R14: 0000000000000001 R15: dffffc0000000000
 local_bh_enable include/linux/bottom_half.h:32 [inline]
 get_next_corpse net/netfilter/nf_conntrack_core.c:2018 [inline]
 nf_ct_iterate_cleanup+0x217/0x4e0 net/netfilter/nf_conntrack_core.c:2041
 nf_ct_iterate_cleanup_net net/netfilter/nf_conntrack_core.c:2126 [inline]
 nf_ct_iterate_cleanup_net+0x133/0x190 net/netfilter/nf_conntrack_core.c:2111
 nf_ct_untimeout+0x2a/0x30 net/netfilter/nf_conntrack_timeout.c:44
 cttimeout_net_exit+0x2b/0x240 net/netfilter/nfnetlink_cttimeout.c:586
 ops_exit_list.isra.0+0xaa/0x150 net/core/net_namespace.c:154
 cleanup_net+0x3fb/0x960 net/core/net_namespace.c:553
 process_one_work+0x989/0x1790 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x354/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

Allocated by task 8432:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_kmalloc mm/kasan/common.c:489 [inline]
 __kasan_kmalloc.constprop.0+0xcf/0xe0 mm/kasan/common.c:462
 kasan_kmalloc+0x9/0x10 mm/kasan/common.c:503
 kmem_cache_alloc_trace+0x151/0x750 mm/slab.c:3555
 kmalloc include/linux/slab.h:547 [inline]
 kzalloc include/linux/slab.h:742 [inline]
 fqdir_init include/net/inet_frag.h:115 [inline]
 nf_ct_net_init+0x4a/0x4d0 net/ipv6/netfilter/nf_conntrack_reasm.c:492
 ops_init+0xb3/0x410 net/core/net_namespace.c:130
 setup_net+0x2d3/0x740 net/core/net_namespace.c:316
 copy_net_ns+0x1df/0x340 net/core/net_namespace.c:439
 create_new_namespaces+0x400/0x7b0 kernel/nsproxy.c:107
 unshare_nsproxy_namespaces+0xc2/0x200 kernel/nsproxy.c:206
 ksys_unshare+0x440/0x980 kernel/fork.c:2719
 __do_sys_unshare kernel/fork.c:2787 [inline]
 __se_sys_unshare kernel/fork.c:2785 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:2785
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 22:
 save_stack+0x23/0x90 mm/kasan/common.c:71
 set_track mm/kasan/common.c:79 [inline]
 __kasan_slab_free+0x102/0x150 mm/kasan/common.c:451
 kasan_slab_free+0xe/0x10 mm/kasan/common.c:459
 __cache_free mm/slab.c:3432 [inline]
 kfree+0xcf/0x220 mm/slab.c:3755
 fqdir_rwork_fn+0x33/0x40 net/ipv4/inet_fragment.c:154
 process_one_work+0x989/0x1790 kernel/workqueue.c:2269
 worker_thread+0x98/0xe40 kernel/workqueue.c:2415
 kthread+0x354/0x420 kernel/kthread.c:255
 ret_from_fork+0x24/0x30 arch/x86/entry/entry_64.S:352

The buggy address belongs to the object at ffff8880a0737d40
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 24 bytes inside of
 512-byte region [ffff8880a0737d40, ffff8880a0737f40)
The buggy address belongs to the page:
page:ffffea000281cdc0 refcount:1 mapcount:0 mapping:ffff8880aa400940 index:0x0
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea00025df148 ffffea000287ac08 ffff8880aa400940
raw: 0000000000000000 ffff8880a07370c0 0000000100000006 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a0737c00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a0737c80: fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc fc
>ffff8880a0737d00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
                                                    ^
 ffff8880a0737d80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a0737e00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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