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BUG: KASAN: slab-out-of-bounds in ____bpf_csum_update net/core/filter.c:1907 [inline]
BUG: KASAN: slab-out-of-bounds in bpf_csum_update+0xb4/0xc0 net/core/filter.c:1901
Read of size 1 at addr ffff8801afd6ccd0 by task syz-executor2/16513

CPU: 1 PID: 16513 Comm: syz-executor2 Not tainted 4.17.0-rc6+ #29
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_load1_noabort+0x14/0x20 mm/kasan/report.c:430
 ____bpf_csum_update net/core/filter.c:1907 [inline]
 bpf_csum_update+0xb4/0xc0 net/core/filter.c:1901

Allocated by task 13580:
 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
 packet_rcv+0x713/0x1810 net/packet/af_packet.c:2076
 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
 process_backlog+0x219/0x760 net/core/dev.c:5391
 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 13617:
 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
 skb_queue_purge+0x19/0x40 net/core/skbuff.c:2853
 packet_release+0x9d1/0xd60 net/packet/af_packet.c:3017
 sock_release+0x96/0x1b0 net/socket.c:594
 sock_close+0x16/0x20 net/socket.c:1149
 __fput+0x34d/0x890 fs/file_table.c:209
 ____fput+0x15/0x20 fs/file_table.c:243
 task_work_run+0x1e4/0x290 kernel/task_work.c:113
 exit_task_work include/linux/task_work.h:22 [inline]
 do_exit+0x1aee/0x2730 kernel/exit.c:865
 do_group_exit+0x16f/0x430 kernel/exit.c:968
 get_signal+0x886/0x1960 kernel/signal.c:2482
 do_signal+0x98/0x2040 arch/x86/kernel/signal.c:810
 exit_to_usermode_loop+0x28a/0x310 arch/x86/entry/common.c:162
 prepare_exit_to_usermode arch/x86/entry/common.c:196 [inline]
 syscall_return_slowpath arch/x86/entry/common.c:265 [inline]
 do_syscall_64+0x6ac/0x800 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe

The buggy address belongs to the object at ffff8801afd6cbc0
 which belongs to the cache skbuff_head_cache of size 232
The buggy address is located 40 bytes to the right of
 232-byte region [ffff8801afd6cbc0, ffff8801afd6cca8)
The buggy address belongs to the page:
page:ffffea0006bf5b00 count:1 mapcount:0 mapping:ffff8801afd6c080 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801afd6c080 0000000000000000 000000010000000c
raw: ffffea0006fe18a0 ffffea00075c1c20 ffff8801d9bdd6c0 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801afd6cb80: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8801afd6cc00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801afd6cc80: fb fb fb fb fb fc fc fc fc fc fc fc fc fc fc fc
                                                 ^
 ffff8801afd6cd00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801afd6cd80: fb fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc
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