syzbot

protocol 0000 is buggy, dev sit0
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BUG: KASAN: use-after-free in skb_is_gso include/linux/skbuff.h:3766 [inline]
BUG: KASAN: use-after-free in virtio_net_hdr_from_skb include/linux/virtio_net.h:64 [inline]
BUG: KASAN: use-after-free in __packet_rcv_vnet net/packet/af_packet.c:1996 [inline]
BUG: KASAN: use-after-free in packet_rcv_vnet net/packet/af_packet.c:2011 [inline]
BUG: KASAN: use-after-free in packet_recvmsg+0xe46/0xf40 net/packet/af_packet.c:3343
Read of size 2 at addr ffff8801b9cbe842 by task syz-executor5/14299

CPU: 1 PID: 14299 Comm: syz-executor5 Not tainted 4.9.101-gaef17a5 #29
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801c9417800 ffffffff81eb1009 ffffea0006e72f80 ffff8801b9cbe842
 0000000000000000 ffff8801b9cbe842 ffff8801b9cbe840 ffff8801c9417838
 ffffffff8156541b ffff8801b9cbe842 0000000000000002 0000000000000000
Call Trace:
 [<ffffffff81eb1009>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb1009>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff8156541b>] print_address_description+0x6c/0x234 mm/kasan/report.c:256
 [<ffffffff81565825>] kasan_report_error mm/kasan/report.c:355 [inline]
 [<ffffffff81565825>] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412
 [<ffffffff81539464>] __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:431
 [<ffffffff8368a386>] skb_is_gso include/linux/skbuff.h:3766 [inline]
 [<ffffffff8368a386>] virtio_net_hdr_from_skb include/linux/virtio_net.h:64 [inline]
 [<ffffffff8368a386>] __packet_rcv_vnet net/packet/af_packet.c:1996 [inline]
 [<ffffffff8368a386>] packet_rcv_vnet net/packet/af_packet.c:2011 [inline]
 [<ffffffff8368a386>] packet_recvmsg+0xe46/0xf40 net/packet/af_packet.c:3343
 [<ffffffff830124c6>] sock_recvmsg_nosec net/socket.c:737 [inline]
 [<ffffffff830124c6>] sock_recvmsg+0xc6/0x110 net/socket.c:744
 [<ffffffff8301275a>] sock_read_iter+0x24a/0x360 net/socket.c:821
 [<ffffffff8156e471>] do_iter_readv_writev+0x301/0x4b0 fs/read_write.c:693
 [<ffffffff81570986>] do_readv_writev+0x2f6/0x7a0 fs/read_write.c:871
 [<ffffffff81570eb4>] vfs_readv+0x84/0xc0 fs/read_write.c:897
 [<ffffffff81570fd6>] do_readv+0xe6/0x260 fs/read_write.c:923
 [<ffffffff81574837>] SYSC_readv fs/read_write.c:1010 [inline]
 [<ffffffff81574837>] SyS_readv+0x27/0x30 fs/read_write.c:1007
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f4893>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Allocated by task 14363:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 save_stack+0x43/0xd0 mm/kasan/kasan.c:505
 set_track mm/kasan/kasan.c:517 [inline]
 kasan_kmalloc+0xc7/0xe0 mm/kasan/kasan.c:609
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:547
 slab_post_alloc_hook mm/slab.h:417 [inline]
 slab_alloc_node mm/slub.c:2715 [inline]
 slab_alloc mm/slub.c:2723 [inline]
 __kmalloc_track_caller+0xdc/0x2b0 mm/slub.c:4232
 __kmalloc_reserve.isra.37+0x33/0xc0 net/core/skbuff.c:138
 __alloc_skb+0x11a/0x600 net/core/skbuff.c:231
 alloc_skb include/linux/skbuff.h:919 [inline]
 alloc_skb_with_frags+0xaf/0x520 net/core/skbuff.c:4679
 sock_alloc_send_pskb+0x5a9/0x750 net/core/sock.c:1893
 packet_alloc_skb net/packet/af_packet.c:2817 [inline]
 packet_snd net/packet/af_packet.c:2908 [inline]
 packet_sendmsg+0x1581/0x4470 net/packet/af_packet.c:2985
 sock_sendmsg_nosec net/socket.c:635 [inline]
 sock_sendmsg+0xcc/0x110 net/socket.c:645
 SYSC_sendto+0x21c/0x370 net/socket.c:1670
 SyS_sendto+0x40/0x50 net/socket.c:1638
 do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Freed by task 14363:
 save_stack_trace+0x16/0x20 arch/x86/kernel/stacktrace.c:57
 save_stack+0x43/0xd0 mm/kasan/kasan.c:505
 set_track mm/kasan/kasan.c:517 [inline]
 kasan_slab_free+0x72/0xc0 mm/kasan/kasan.c:582
 slab_free_hook mm/slub.c:1355 [inline]
 slab_free_freelist_hook mm/slub.c:1377 [inline]
 slab_free mm/slub.c:2958 [inline]
 kfree+0xfb/0x310 mm/slub.c:3878
 skb_free_head+0x8b/0xb0 net/core/skbuff.c:580
 skb_release_data+0x329/0x400 net/core/skbuff.c:611
 skb_release_all+0x4a/0x60 net/core/skbuff.c:670
 __kfree_skb+0x15/0x20 net/core/skbuff.c:684
 kfree_skb+0xcc/0x340 net/core/skbuff.c:705
 sit_tunnel_xmit+0xfb/0x2590 net/ipv6/sit.c:1033
 __netdev_start_xmit include/linux/netdevice.h:4062 [inline]
 netdev_start_xmit include/linux/netdevice.h:4071 [inline]
 xmit_one net/core/dev.c:2955 [inline]
 dev_hard_start_xmit+0x197/0x8b0 net/core/dev.c:2971
 __dev_queue_xmit+0x19a5/0x2080 net/core/dev.c:3451
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3484
 packet_snd net/packet/af_packet.c:2960 [inline]
 packet_sendmsg+0x1eff/0x4470 net/packet/af_packet.c:2985
 sock_sendmsg_nosec net/socket.c:635 [inline]
 sock_sendmsg+0xcc/0x110 net/socket.c:645
 SYSC_sendto+0x21c/0x370 net/socket.c:1670
 SyS_sendto+0x40/0x50 net/socket.c:1638
 do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 entry_SYSCALL_64_after_swapgs+0x5d/0xdb

The buggy address belongs to the object at ffff8801b9cbe780
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 194 bytes inside of
 512-byte region [ffff8801b9cbe780, ffff8801b9cbe980)
The buggy address belongs to the page:
page:ffffea0006e72f80 count:1 mapcount:0 mapping:          (null) index:0x0 compound_mapcount: 0
flags: 0x8000000000004080(slab|head)
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801b9cbe700: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
 ffff8801b9cbe780: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801b9cbe800: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                           ^
 ffff8801b9cbe880: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801b9cbe900: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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