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BUG: KASAN: slab-out-of-bounds in bpf_skb_proto_xlat net/core/filter.c:2151 [inline]
BUG: KASAN: slab-out-of-bounds in ____bpf_skb_change_proto net/core/filter.c:2189 [inline]
BUG: KASAN: slab-out-of-bounds in bpf_skb_change_proto+0xcc2/0x1080 net/core/filter.c:2164
Read of size 2 at addr ffff8881c96c4c78 by task syz-executor.1/9541

CPU: 0 PID: 9541 Comm: syz-executor.1 Not tainted 4.14.142+ #0
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xca/0x134 lib/dump_stack.c:53
 print_address_description+0x60/0x226 mm/kasan/report.c:187
 __kasan_report.cold+0x1a/0x41 mm/kasan/report.c:316
 bpf_skb_proto_xlat net/core/filter.c:2151 [inline]
 ____bpf_skb_change_proto net/core/filter.c:2189 [inline]
 bpf_skb_change_proto+0xcc2/0x1080 net/core/filter.c:2164
 ___bpf_prog_run+0x2478/0x5510 kernel/bpf/core.c:1086

Allocated by task 8065:
 save_stack mm/kasan/common.c:76 [inline]
 set_track mm/kasan/common.c:85 [inline]
 __kasan_kmalloc.part.0+0x53/0xc0 mm/kasan/common.c:495
 slab_post_alloc_hook mm/slab.h:439 [inline]
 slab_alloc_node mm/slub.c:2792 [inline]
 slab_alloc mm/slub.c:2800 [inline]
 kmem_cache_alloc+0xee/0x360 mm/slub.c:2805
 kmem_cache_alloc_node include/linux/slab.h:361 [inline]
 __alloc_skb+0xea/0x5c0 net/core/skbuff.c:193
 alloc_skb include/linux/skbuff.h:980 [inline]
 nlmsg_new include/net/netlink.h:511 [inline]
 netlink_ack+0x228/0x980 net/netlink/af_netlink.c:2359
 netlink_rcv_skb+0x2c4/0x3a0 net/netlink/af_netlink.c:2438
 genl_rcv+0x24/0x40 net/netlink/genetlink.c:636
 netlink_unicast_kernel net/netlink/af_netlink.c:1286 [inline]
 netlink_unicast+0x478/0x650 net/netlink/af_netlink.c:1312
 netlink_sendmsg+0x66a/0xbe0 net/netlink/af_netlink.c:1877
 sock_sendmsg_nosec net/socket.c:646 [inline]
 sock_sendmsg+0xb7/0x100 net/socket.c:656
 ___sys_sendmsg+0x752/0x890 net/socket.c:2062
 __sys_sendmsg+0xb6/0x150 net/socket.c:2096
 SYSC_sendmsg net/socket.c:2107 [inline]
 SyS_sendmsg+0x27/0x40 net/socket.c:2103
 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292
 entry_SYSCALL_64_after_hwframe+0x42/0xb7
 0xffffffffffffffff

Freed by task 8077:
 save_stack mm/kasan/common.c:76 [inline]
 set_track mm/kasan/common.c:85 [inline]
 __kasan_slab_free+0x164/0x210 mm/kasan/common.c:457
 slab_free_hook mm/slub.c:1407 [inline]
 slab_free_freelist_hook mm/slub.c:1458 [inline]
 slab_free mm/slub.c:3039 [inline]
 kmem_cache_free+0xd7/0x3b0 mm/slub.c:3055
 kfree_skbmem net/core/skbuff.c:586 [inline]
 kfree_skbmem+0xa0/0x110 net/core/skbuff.c:580
 __kfree_skb net/core/skbuff.c:646 [inline]
 kfree_skb+0xeb/0x370 net/core/skbuff.c:663
 skb_queue_purge+0x14/0x30 net/core/skbuff.c:2855
 netlink_sock_destruct+0xf9/0x280 net/netlink/af_netlink.c:371
 __sk_destruct+0x4c/0x5f0 net/core/sock.c:1556
 sk_destruct+0x5d/0x70 net/core/sock.c:1591
 __sk_free+0x4c/0x220 net/core/sock.c:1599
 sk_free+0x2c/0x40 net/core/sock.c:1610
 deferred_put_nlk_sk+0xee/0x260 net/netlink/af_netlink.c:711
 __rcu_reclaim kernel/rcu/rcu.h:195 [inline]
 rcu_do_batch kernel/rcu/tree.c:2699 [inline]
 invoke_rcu_callbacks kernel/rcu/tree.c:2962 [inline]
 __rcu_process_callbacks kernel/rcu/tree.c:2929 [inline]
 rcu_process_callbacks+0x59f/0xf60 kernel/rcu/tree.c:2946
 __do_softirq+0x234/0x9ec kernel/softirq.c:288

The buggy address belongs to the object at ffff8881c96c4b40
 which belongs to the cache skbuff_head_cache of size 224
The buggy address is located 88 bytes to the right of
 224-byte region [ffff8881c96c4b40, ffff8881c96c4c20)
The buggy address belongs to the page:
page:ffffea000725b100 count:1 mapcount:0 mapping:          (null) index:0xffff8881c96c4b40
flags: 0x4000000000000200(slab)
raw: 4000000000000200 0000000000000000 ffff8881c96c4b40 00000001800c000a
raw: ffffea00074e4280 0000000200000002 ffff8881dab70200 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8881c96c4b00: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8881c96c4b80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8881c96c4c00: fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc fc
                                                                ^
 ffff8881c96c4c80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8881c96c4d00: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
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