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BUG: KASAN: slab-out-of-bounds in skb_headlen include/linux/skbuff.h:1898 [inline]
BUG: KASAN: slab-out-of-bounds in pskb_may_pull include/linux/skbuff.h:2112 [inline]
BUG: KASAN: slab-out-of-bounds in skb_ensure_writable+0x290/0x2e0 net/core/skbuff.c:5022
Read of size 4 at addr ffff8801d60090f8 by task syz-executor5/5605

CPU: 1 PID: 5605 Comm: syz-executor5 Not tainted 4.14.71+ #8
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0xb9/0x11b lib/dump_stack.c:53
 print_address_description+0x60/0x22b mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report.cold.6+0x11b/0x2dd mm/kasan/report.c:409
 skb_headlen include/linux/skbuff.h:1898 [inline]
 pskb_may_pull include/linux/skbuff.h:2112 [inline]
 skb_ensure_writable+0x290/0x2e0 net/core/skbuff.c:5022
 __bpf_try_make_writable net/core/filter.c:1403 [inline]
 bpf_try_make_writable net/core/filter.c:1409 [inline]
 ____bpf_l3_csum_replace net/core/filter.c:1530 [inline]
 bpf_l3_csum_replace+0x5f/0x340 net/core/filter.c:1521
 ___bpf_prog_run+0x248e/0x5c70 kernel/bpf/core.c:1012

Allocated by task 349:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc.part.1+0x4f/0xd0 mm/kasan/kasan.c:551
 slab_post_alloc_hook mm/slab.h:442 [inline]
 slab_alloc_node mm/slub.c:2723 [inline]
 slab_alloc mm/slub.c:2731 [inline]
 kmem_cache_alloc+0xe4/0x2b0 mm/slub.c:2736
 kmem_cache_alloc_node include/linux/slab.h:361 [inline]
 __alloc_skb+0xd8/0x550 net/core/skbuff.c:193
 alloc_skb include/linux/skbuff.h:980 [inline]
 alloc_skb_with_frags+0xab/0x500 net/core/skbuff.c:5170
 sock_alloc_send_pskb+0x55e/0x6e0 net/core/sock.c:2075
 unix_dgram_sendmsg+0x37b/0xf50 net/unix/af_unix.c:1681
 sock_sendmsg_nosec net/socket.c:645 [inline]
 sock_sendmsg+0xb5/0x100 net/socket.c:655
 SYSC_sendto net/socket.c:1762 [inline]
 SyS_sendto+0x211/0x340 net/socket.c:1730
 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

Freed by task 191:
 save_stack mm/kasan/kasan.c:447 [inline]
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0xac/0x190 mm/kasan/kasan.c:524
 slab_free_hook mm/slub.c:1389 [inline]
 slab_free_freelist_hook mm/slub.c:1410 [inline]
 slab_free mm/slub.c:2966 [inline]
 kmem_cache_free+0x12d/0x350 mm/slub.c:2988
 kfree_skbmem+0x9e/0x100 net/core/skbuff.c:582
 __kfree_skb net/core/skbuff.c:642 [inline]
 consume_skb+0xc9/0x330 net/core/skbuff.c:701
 skb_free_datagram+0x15/0xd0 net/core/datagram.c:331
 unix_dgram_recvmsg+0x762/0xd20 net/unix/af_unix.c:2183
 sock_recvmsg_nosec net/socket.c:818 [inline]
 sock_recvmsg+0xc0/0x100 net/socket.c:825
 SYSC_recvfrom net/socket.c:1814 [inline]
 SyS_recvfrom+0x1d2/0x310 net/socket.c:1786
 do_syscall_64+0x19b/0x4b0 arch/x86/entry/common.c:289
 entry_SYSCALL_64_after_hwframe+0x42/0xb7

The buggy address belongs to the object at ffff8801d6009000
 which belongs to the cache skbuff_head_cache of size 224
The buggy address is located 24 bytes to the right of
 224-byte region [ffff8801d6009000, ffff8801d60090e0)
The buggy address belongs to the page:
page:ffffea0007580240 count:1 mapcount:0 mapping:          (null) index:0x0
flags: 0x4000000000000100(slab)
raw: 4000000000000100 0000000000000000 0000000000000000 00000001800c000c
raw: 0000000000000000 0000000100000001 ffff8801dab70200 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d6008f80: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff8801d6009000: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801d6009080: fb fb fb fb fb fb fb fb fb fb fb fb fc fc fc fc
                                                                ^
 ffff8801d6009100: fc fc fc fc fc fc fc fc fb fb fb fb fb fb fb fb
 ffff8801d6009180: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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