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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 ffff8880a9984518 by task syz-executor.2/25144

CPU: 1 PID: 25144 Comm: syz-executor.2 Not tainted 5.2.0-rc1+ #3
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
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:preempt_count arch/x86/include/asm/preempt.h:26 [inline]
RIP: 0010:check_kcov_mode kernel/kcov.c:68 [inline]
RIP: 0010:__sanitizer_cov_trace_pc+0x11/0x50 kernel/kcov.c:102
Code: 48 c7 05 de 6a f5 08 00 00 00 00 e9 a4 e9 ff ff 90 90 90 90 90 90 90 90 90 55 48 89 e5 48 8b 75 08 65 48 8b 04 25 c0 fd 01 00 <65> 8b 15 00 59 91 7e 81 e2 00 01 1f 00 75 2b 8b 90 e0 12 00 00 83
RSP: 0018:ffff88808ad7f210 EFLAGS: 00000246 ORIG_RAX: ffffffffffffff13
RAX: ffff88806b618000 RBX: ffff88808ad7f310 RCX: ffffffff815fe052
RDX: 0000000000000000 RSI: ffffffff815fe05c RDI: 0000000000000005
RBP: ffff88808ad7f210 R08: ffff88806b618000 R09: ffff88808ad7f2b0
R10: ffff88808ad7f280 R11: ffff88808ad7f290 R12: 0000000000000009
R13: ffffffff8711d027 R14: 0000000000000000 R15: 0000000000000000
 stack_trace_consume_entry+0xcc/0x190 kernel/stacktrace.c:93
 arch_stack_walk+0x71/0xf0 arch/x86/kernel/stacktrace.c:27
 stack_trace_save+0xac/0xe0 kernel/stacktrace.c:123
 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_node_trace+0x153/0x720 mm/slab.c:3599
 __do_kmalloc_node mm/slab.c:3619 [inline]
 __kmalloc_node_track_caller+0x3d/0x70 mm/slab.c:3634
 __kmalloc_reserve.isra.0+0x40/0xf0 net/core/skbuff.c:142
 __alloc_skb+0x10b/0x5e0 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1058 [inline]
 nlmsg_new include/net/netlink.h:885 [inline]
 mpls_netconf_notify_devconf+0x57/0x120 net/mpls/af_mpls.c:1190
 mpls_dev_sysctl_register+0x220/0x2f0 net/mpls/af_mpls.c:1428
 mpls_add_dev net/mpls/af_mpls.c:1475 [inline]
 mpls_dev_notify+0x277/0x890 net/mpls/af_mpls.c:1601
 notifier_call_chain+0xc2/0x230 kernel/notifier.c:95
 __raw_notifier_call_chain kernel/notifier.c:396 [inline]
 raw_notifier_call_chain+0x2e/0x40 kernel/notifier.c:403
 call_netdevice_notifiers_info+0x3f/0x90 net/core/dev.c:1753
 call_netdevice_notifiers_extack net/core/dev.c:1765 [inline]
 call_netdevice_notifiers net/core/dev.c:1779 [inline]
 register_netdevice+0xa4d/0xff0 net/core/dev.c:8772
 __ip_tunnel_create+0x36b/0x530 net/ipv4/ip_tunnel.c:282
 ip_tunnel_init_net+0x375/0x9e0 net/ipv4/ip_tunnel.c:1073
 erspan_init_net+0x2a/0x30 net/ipv4/ip_gre.c:1594
 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:2692
 __do_sys_unshare kernel/fork.c:2760 [inline]
 __se_sys_unshare kernel/fork.c:2758 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:2758
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45bd47
Code: 00 00 00 b8 63 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 1d 8d fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 b8 10 01 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 fd 8c fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffe31d304a8 EFLAGS: 00000206 ORIG_RAX: 0000000000000110
RAX: ffffffffffffffda RBX: 000000000075c9a8 RCX: 000000000045bd47
RDX: 0000000000000000 RSI: 00007ffe31d30450 RDI: 0000000040000000
RBP: 00000000000000f8 R08: 0000000000000000 R09: 0000000000000005
R10: 0000000000000000 R11: 0000000000000206 R12: 000000000075c9a8
R13: 00007ffe31d30718 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 22105:
 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]
 ipv4_frags_init_net+0x48/0x4e0 net/ipv4/ip_fragment.c:645
 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:2692
 __do_sys_unshare kernel/fork.c:2760 [inline]
 __se_sys_unshare kernel/fork.c:2758 [inline]
 __x64_sys_unshare+0x31/0x40 kernel/fork.c:2758
 do_syscall_64+0xfd/0x680 arch/x86/entry/common.c:301
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

Freed by task 9786:
 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 ffff8880a9984500
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 24 bytes inside of
 512-byte region [ffff8880a9984500, ffff8880a9984700)
The buggy address belongs to the page:
page:ffffea0002a66100 refcount:1 mapcount:0 mapping:ffff8880aa400940 index:0x0
flags: 0x1fffc0000000200(slab)
raw: 01fffc0000000200 ffffea000234b108 ffffea0001b3d948 ffff8880aa400940
raw: 0000000000000000 ffff8880a9984000 0000000100000006 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8880a9984400: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a9984480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8880a9984500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                            ^
 ffff8880a9984580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8880a9984600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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