==================================================================
BUG: KASAN: use-after-free in __read_once_size include/linux/compiler.h:218 [inline]
BUG: KASAN: use-after-free in atomic_read arch/x86/include/asm/atomic.h:26 [inline]
BUG: KASAN: use-after-free in __atomic_add_unless arch/x86/include/asm/atomic.h:211 [inline]
BUG: KASAN: use-after-free in atomic_add_unless include/linux/atomic.h:437 [inline]
BUG: KASAN: use-after-free in sk_dst_get include/net/sock.h:1745 [inline]
BUG: KASAN: use-after-free in sk_dst_check+0x347/0x380 net/core/sock.c:546
Read of size 4 at addr ffff8800badaa580 by task syz-executor.2/2467

CPU: 0 PID: 2467 Comm: syz-executor.2 Not tainted 4.4.174+ #17
 0000000000000000 4337e772e4cc98ec ffff8801d8b3f698 ffffffff81aad1a1
 0000000000000000 ffffea0002eb6a80 ffff8800badaa580 0000000000000004
 0000000000000000 ffff8801d8b3f6d0 ffffffff81490120 0000000000000000
Call Trace:
 [<ffffffff81aad1a1>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81aad1a1>] dump_stack+0xc1/0x120 lib/dump_stack.c:51
 [<ffffffff81490120>] print_address_description+0x6f/0x21b mm/kasan/report.c:252
 [<ffffffff81490358>] kasan_report_error mm/kasan/report.c:351 [inline]
 [<ffffffff81490358>] kasan_report mm/kasan/report.c:408 [inline]
 [<ffffffff81490358>] kasan_report.cold+0x8c/0x2be mm/kasan/report.c:393
 [<ffffffff81484eb4>] __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:428
 [<ffffffff821e1de7>] __read_once_size include/linux/compiler.h:218 [inline]
 [<ffffffff821e1de7>] atomic_read arch/x86/include/asm/atomic.h:26 [inline]
 [<ffffffff821e1de7>] __atomic_add_unless arch/x86/include/asm/atomic.h:211 [inline]
 [<ffffffff821e1de7>] atomic_add_unless include/linux/atomic.h:437 [inline]
 [<ffffffff821e1de7>] sk_dst_get include/net/sock.h:1745 [inline]
 [<ffffffff821e1de7>] sk_dst_check+0x347/0x380 net/core/sock.c:546
 [<ffffffff8247f61f>] udp_sendmsg+0x114f/0x1c60 net/ipv4/udp.c:1019
 [<ffffffff824a8b42>] inet_sendmsg+0x202/0x4d0 net/ipv4/af_inet.c:755
 [<ffffffff821d838e>] sock_sendmsg_nosec net/socket.c:638 [inline]
 [<ffffffff821d838e>] sock_sendmsg+0xbe/0x110 net/socket.c:648
 [<ffffffff821d9e69>] ___sys_sendmsg+0x369/0x890 net/socket.c:1975
 [<ffffffff821dd386>] __sys_sendmmsg+0x1d6/0x2e0 net/socket.c:2053
 [<ffffffff822ace22>] C_SYSC_sendmmsg net/compat.c:731 [inline]
 [<ffffffff822ace22>] compat_SyS_sendmmsg+0x32/0x40 net/compat.c:728
 [<ffffffff8100603d>] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 [<ffffffff8100603d>] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397
 [<ffffffff8271a350>] sysenter_flags_fixed+0xd/0x1a

Allocated by task 2467:
 [<ffffffff8102e3c6>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff81483f22>] save_stack mm/kasan/kasan.c:512 [inline]
 [<ffffffff81483f22>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff81483f22>] kasan_kmalloc.part.0+0x62/0xf0 mm/kasan/kasan.c:616
 [<ffffffff81484197>] kasan_kmalloc+0xb7/0xd0 mm/kasan/kasan.c:601
 [<ffffffff8148475f>] kasan_slab_alloc+0xf/0x20 mm/kasan/kasan.c:554
 [<ffffffff8147fe9c>] slab_post_alloc_hook mm/slub.c:1349 [inline]
 [<ffffffff8147fe9c>] slab_alloc_node mm/slub.c:2615 [inline]
 [<ffffffff8147fe9c>] slab_alloc mm/slub.c:2623 [inline]
 [<ffffffff8147fe9c>] kmem_cache_alloc+0xdc/0x2c0 mm/slub.c:2628
 [<ffffffff82258393>] dst_alloc+0xf3/0x1b0 net/core/dst.c:210
 [<ffffffff823b12c0>] ipv4_blackhole_route+0x30/0x720 net/ipv4/route.c:2396
 [<ffffffff825523f4>] make_blackhole net/xfrm/xfrm_policy.c:2161 [inline]
 [<ffffffff825523f4>] xfrm_lookup_route net/xfrm/xfrm_policy.c:2331 [inline]
 [<ffffffff825523f4>] xfrm_lookup_route+0xf4/0x140 net/xfrm/xfrm_policy.c:2322
 [<ffffffff823a5a23>] ip_route_output_flow+0x93/0xa0 net/ipv4/route.c:2437
 [<ffffffff8247fa07>] udp_sendmsg+0x1537/0x1c60 net/ipv4/udp.c:1040
 [<ffffffff824a8b42>] inet_sendmsg+0x202/0x4d0 net/ipv4/af_inet.c:755
 [<ffffffff821d838e>] sock_sendmsg_nosec net/socket.c:638 [inline]
 [<ffffffff821d838e>] sock_sendmsg+0xbe/0x110 net/socket.c:648
 [<ffffffff821d9e69>] ___sys_sendmsg+0x369/0x890 net/socket.c:1975
 [<ffffffff821dd386>] __sys_sendmmsg+0x1d6/0x2e0 net/socket.c:2053
 [<ffffffff822ace22>] C_SYSC_sendmmsg net/compat.c:731 [inline]
 [<ffffffff822ace22>] compat_SyS_sendmmsg+0x32/0x40 net/compat.c:728
 [<ffffffff8100603d>] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 [<ffffffff8100603d>] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397
 [<ffffffff8271a350>] sysenter_flags_fixed+0xd/0x1a

Freed by task 348:
 [<ffffffff8102e3c6>] save_stack_trace+0x26/0x50 arch/x86/kernel/stacktrace.c:63
 [<ffffffff81484820>] save_stack mm/kasan/kasan.c:512 [inline]
 [<ffffffff81484820>] set_track mm/kasan/kasan.c:524 [inline]
 [<ffffffff81484820>] kasan_slab_free+0xb0/0x190 mm/kasan/kasan.c:589
 [<ffffffff8148157e>] slab_free_hook mm/slub.c:1383 [inline]
 [<ffffffff8148157e>] slab_free_freelist_hook mm/slub.c:1405 [inline]
 [<ffffffff8148157e>] slab_free mm/slub.c:2859 [inline]
 [<ffffffff8148157e>] kmem_cache_free+0xbe/0x350 mm/slub.c:2881
 [<ffffffff82256eef>] dst_destroy+0x26f/0x330 net/core/dst.c:270
 [<ffffffff8225716e>] dst_gc_task+0x1be/0x530 net/core/dst.c:89
 [<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

The buggy address belongs to the object at ffff8800badaa500
 which belongs to the cache ip_dst_cache of size 208
The buggy address is located 128 bytes inside of
 208-byte region [ffff8800badaa500, ffff8800badaa5d0)
The buggy address belongs to the page:
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory accessgeneral protection fault: 0000 [#1] PREEMPT SMP KASAN
Modules linked in:
CPU: 1 PID: 2451 Comm: syz-executor.3 Not tainted 4.4.174+ #17
task: ffff8801cfb32f80 task.stack: ffff8800a4b60000
RIP: 0010:[<ffffffff81b0c22e>]  [<ffffffff81b0c22e>] lookup_object lib/debugobjects.c:120 [inline]
RIP: 0010:[<ffffffff81b0c22e>]  [<ffffffff81b0c22e>] debug_object_activate+0x19e/0x470 lib/debugobjects.c:408
RSP: 0018:ffff8800a4b67430  EFLAGS: 00010002
RAX: 1ffffd40005d6d50 RBX: 0000000000000014 RCX: ffffffff82ea7280
RDX: 0000000000000013 RSI: 0000000000000001 RDI: 0000000000000098
RBP: ffff8800a4b67520 R08: ffffffff840a5388 R09: 0000000000000292
R10: ffffffff83a41a80 R11: 0000000000000000 R12: 0000000000000080
R13: ffff8800b37d4e00 R14: dffffc0000000000 R15: 1ffff1001496ce8a
FS:  0000000000000000(0000) GS:ffff8801db700000(0063) knlGS:00000000f5542b40
CS:  0010 DS: 002b ES: 002b CR0: 0000000080050033
CR2: 00000000093e91b4 CR3: 00000000b9e80000 CR4: 00000000001606b0
Stack:
 ffff8801cfb33848 1ffff1001496ce8a ffffffff82ea7280 ffffffff840a5388
 0000000041b58ab3 ffffffff82c76911 ffffffff81b0c090 1ffff1001496ce90
 ffffffff00000001 1ffffffff0506d10 0000000000000000 0000000000000000
Call Trace:
 [<ffffffff812446c5>] debug_rcu_head_queue kernel/rcu/rcu.h:75 [inline]
 [<ffffffff812446c5>] __call_rcu.constprop.0+0x35/0x930 kernel/rcu/tree.c:3059
 [<ffffffff81244ff5>] kfree_call_rcu+0x15/0x20 kernel/rcu/tree.c:3148
 [<ffffffff8230e24a>] nf_ct_ext_free include/net/netfilter/nf_conntrack_extend.h:89 [inline]
 [<ffffffff8230e24a>] nf_conntrack_free+0xaa/0x120 net/netfilter/nf_conntrack_core.c:905
 [<ffffffff823116f0>] destroy_conntrack+0x270/0x380 net/netfilter/nf_conntrack_core.c:365
 [<ffffffff822f6cd9>] nf_conntrack_destroy+0x99/0x1a0 net/netfilter/core.c:389
 [<ffffffff821eff3a>] nf_conntrack_put include/linux/skbuff.h:3377 [inline]
 [<ffffffff821eff3a>] skb_release_head_state+0x15a/0x210 net/core/skbuff.c:649
 [<ffffffff821fd0e6>] skb_release_all+0x16/0x60 net/core/skbuff.c:659
 [<ffffffff821fd257>] __kfree_skb net/core/skbuff.c:675 [inline]
 [<ffffffff821fd257>] kfree_skb+0xf7/0x400 net/core/skbuff.c:696
 [<ffffffff82256726>] dst_discard_out+0x16/0x20 net/core/dst.c:149
 [<ffffffff823cd21c>] dst_output include/net/dst.h:498 [inline]
 [<ffffffff823cd21c>] ip_local_out+0x9c/0x180 net/ipv4/ip_output.c:119
 [<ffffffff823d300e>] ip_send_skb+0x3e/0xc0 net/ipv4/ip_output.c:1453
 [<ffffffff82478ded>] udp_send_skb+0x4fd/0xc70 net/ipv4/udp.c:842
 [<ffffffff8247fb9f>] udp_sendmsg+0x16cf/0x1c60 net/ipv4/udp.c:1072
 [<ffffffff824a8b42>] inet_sendmsg+0x202/0x4d0 net/ipv4/af_inet.c:755
 [<ffffffff821d838e>] sock_sendmsg_nosec net/socket.c:638 [inline]
 [<ffffffff821d838e>] sock_sendmsg+0xbe/0x110 net/socket.c:648
 [<ffffffff821d9e69>] ___sys_sendmsg+0x369/0x890 net/socket.c:1975
 [<ffffffff821dd386>] __sys_sendmmsg+0x1d6/0x2e0 net/socket.c:2053
 [<ffffffff822ace22>] C_SYSC_sendmmsg net/compat.c:731 [inline]
 [<ffffffff822ace22>] compat_SyS_sendmmsg+0x32/0x40 net/compat.c:728
 [<ffffffff8100603d>] do_syscall_32_irqs_on arch/x86/entry/common.c:330 [inline]
 [<ffffffff8100603d>] do_fast_syscall_32+0x32d/0xa90 arch/x86/entry/common.c:397
 [<ffffffff8271a350>] sysenter_flags_fixed+0xd/0x1a
Code: 48 c1 e8 03 42 80 3c 30 00 0f 85 44 02 00 00 4d 8b 24 24 4d 85 e4 0f 84 b5 00 00 00 49 8d 7c 24 18 83 c3 01 48 89 fa 48 c1 ea 03 <42> 80 3c 32 00 0f 85 f5 01 00 00 4d 3b 6c 24 18 75 c0 4d 8d 74 
RIP  [<ffffffff81b0c22e>] lookup_object lib/debugobjects.c:120 [inline]
RIP  [<ffffffff81b0c22e>] debug_object_activate+0x19e/0x470 lib/debugobjects.c:408
 RSP <ffff8800a4b67430>
---[ end trace 0f040f0d18089b95 ]---