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BUG: KASAN: slab-out-of-bounds in ____bpf_skb_change_head net/core/filter.c:2921 [inline]
BUG: KASAN: slab-out-of-bounds in bpf_skb_change_head+0x80c/0x9d0 net/core/filter.c:2917
Read of size 4 at addr ffff8801b6472540 by task syz-executor1/24190

CPU: 0 PID: 24190 Comm: syz-executor1 Not tainted 4.17.0-rc7+ #38
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1b9/0x294 lib/dump_stack.c:113
 print_address_description+0x6c/0x20b mm/kasan/report.c:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report.cold.7+0x242/0x2fe mm/kasan/report.c:412
 __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432
 ____bpf_skb_change_head net/core/filter.c:2921 [inline]
 bpf_skb_change_head+0x80c/0x9d0 net/core/filter.c:2917

Allocated by task 4510:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 kasan_kmalloc+0xc4/0xe0 mm/kasan/kasan.c:553
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:490
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3554
 skb_clone+0x1ed/0x4f0 net/core/skbuff.c:1282
 skb_share_check include/linux/skbuff.h:1516 [inline]
 packet_rcv_spkt+0x59a/0x730 net/packet/af_packet.c:1816
 deliver_skb net/core/dev.c:1925 [inline]
 deliver_ptype_list_skb net/core/dev.c:1940 [inline]
 __netif_receive_skb_core+0x1bdb/0x3650 net/core/dev.c:4629
 __netif_receive_skb+0x2c/0x1e0 net/core/dev.c:4711
 netif_receive_skb_internal+0x126/0x7b0 net/core/dev.c:4785
 napi_skb_finish net/core/dev.c:5147 [inline]
 napi_gro_receive+0x44d/0x5a0 net/core/dev.c:5178
 receive_buf+0xc6a/0x2bb0 drivers/net/virtio_net.c:991
 virtnet_receive drivers/net/virtio_net.c:1246 [inline]
 virtnet_poll+0x3c8/0xdb5 drivers/net/virtio_net.c:1328
 napi_poll net/core/dev.c:5789 [inline]
 net_rx_action+0x7b7/0x1930 net/core/dev.c:5855
 __do_softirq+0x2e0/0xaf5 kernel/softirq.c:285

Freed by task 4510:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:448
 set_track mm/kasan/kasan.c:460 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:521
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:528
 __cache_free mm/slab.c:3498 [inline]
 kmem_cache_free+0x86/0x2d0 mm/slab.c:3756
 kfree_skbmem+0x13c/0x210 net/core/skbuff.c:582
 __kfree_skb net/core/skbuff.c:642 [inline]
 kfree_skb+0x19d/0x560 net/core/skbuff.c:659
 packet_rcv_spkt+0x126/0x730 net/packet/af_packet.c:1847
 deliver_skb net/core/dev.c:1925 [inline]
 deliver_ptype_list_skb net/core/dev.c:1940 [inline]
 __netif_receive_skb_core+0x1bdb/0x3650 net/core/dev.c:4629
 __netif_receive_skb+0x2c/0x1e0 net/core/dev.c:4711
 netif_receive_skb_internal+0x126/0x7b0 net/core/dev.c:4785
 napi_skb_finish net/core/dev.c:5147 [inline]
 napi_gro_receive+0x44d/0x5a0 net/core/dev.c:5178
 receive_buf+0xc6a/0x2bb0 drivers/net/virtio_net.c:991
 virtnet_receive drivers/net/virtio_net.c:1246 [inline]
 virtnet_poll+0x3c8/0xdb5 drivers/net/virtio_net.c:1328
 napi_poll net/core/dev.c:5789 [inline]
 net_rx_action+0x7b7/0x1930 net/core/dev.c:5855
 __do_softirq+0x2e0/0xaf5 kernel/softirq.c:285

The buggy address belongs to the object at ffff8801b6472440
 which belongs to the cache skbuff_head_cache of size 232
The buggy address is located 24 bytes to the right of
 232-byte region [ffff8801b6472440, ffff8801b6472528)
The buggy address belongs to the page:
page:ffffea0006d91c80 count:1 mapcount:0 mapping:ffff8801b6472080 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801b6472080 0000000000000000 000000010000000c
raw: ffffea0006dbfba0 ffffea00075c3aa0 ffff8801d9bdd6c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801b6472400: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8801b6472480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801b6472500: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
                                           ^
 ffff8801b6472580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801b6472600: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
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