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BUG: KASAN: use-after-free in __tcp_hdrlen include/linux/tcp.h:35 [inline]
BUG: KASAN: use-after-free in tcp_hdrlen include/linux/tcp.h:40 [inline]
BUG: KASAN: use-after-free in qdisc_pkt_len_init net/core/dev.c:3160 [inline]
BUG: KASAN: use-after-free in __dev_queue_xmit+0x20d3/0x2200 net/core/dev.c:3465
Read of size 2 at addr ffff8801ce7d3a78 by task syzkaller329098/3159

CPU: 0 PID: 3159 Comm: syzkaller329098 Not tainted 4.15.0-rc4-next-20171221+ #78
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:17 [inline]
 dump_stack+0x194/0x257 lib/dump_stack.c:53
 print_address_description+0x73/0x250 mm/kasan/report.c:252
 kasan_report_error mm/kasan/report.c:351 [inline]
 kasan_report+0x25b/0x340 mm/kasan/report.c:409
 __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:428
 __tcp_hdrlen include/linux/tcp.h:35 [inline]
 tcp_hdrlen include/linux/tcp.h:40 [inline]
 qdisc_pkt_len_init net/core/dev.c:3160 [inline]
 __dev_queue_xmit+0x20d3/0x2200 net/core/dev.c:3465
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3554
 packet_snd net/packet/af_packet.c:2943 [inline]
 packet_sendmsg+0x3ad5/0x60a0 net/packet/af_packet.c:2968
 sock_sendmsg_nosec net/socket.c:628 [inline]
 sock_sendmsg+0xca/0x110 net/socket.c:638
 sock_write_iter+0x31a/0x5d0 net/socket.c:907
 call_write_iter include/linux/fs.h:1776 [inline]
 new_sync_write fs/read_write.c:469 [inline]
 __vfs_write+0x684/0x970 fs/read_write.c:482
 vfs_write+0x189/0x510 fs/read_write.c:544
 SYSC_write fs/read_write.c:589 [inline]
 SyS_write+0xef/0x220 fs/read_write.c:581
 entry_SYSCALL_64_fastpath+0x1f/0x96
RIP: 0033:0x444b89
RSP: 002b:00000000007eff78 EFLAGS: 00000293 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 00007ffeeaf812d0 RCX: 0000000000444b89
RDX: 000000000000005d RSI: 0000000020384000 RDI: 0000000000000005
RBP: 0000000000000000 R08: 0000000120080522 R09: 0000000120080522
R10: 0000000120080522 R11: 0000000000000293 R12: 0000000000402780
R13: 0000000000402810 R14: 0000000000000000 R15: 0000000000000000

Allocated by task 1636:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_kmalloc+0xad/0xe0 mm/kasan/kasan.c:551
 __do_kmalloc_node mm/slab.c:3673 [inline]
 __kmalloc_node_track_caller+0x47/0x70 mm/slab.c:3687
 __kmalloc_reserve.isra.41+0x41/0xd0 net/core/skbuff.c:137
 __alloc_skb+0x13b/0x780 net/core/skbuff.c:205
 alloc_skb include/linux/skbuff.h:983 [inline]
 kobject_uevent_net_broadcast lib/kobject_uevent.c:319 [inline]
 kobject_uevent_env+0x6e3/0xbc0 lib/kobject_uevent.c:508
 kobject_synth_uevent+0x514/0xad0 lib/kobject_uevent.c:204
 uevent_store+0x27/0x50 drivers/base/core.c:982
 dev_attr_store+0x5c/0x90 drivers/base/core.c:702
 sysfs_kf_write+0x107/0x160 fs/sysfs/file.c:141
 kernfs_fop_write+0x2bc/0x450 fs/kernfs/file.c:316
 __vfs_write+0xef/0x970 fs/read_write.c:480
 vfs_write+0x189/0x510 fs/read_write.c:544
 SYSC_write fs/read_write.c:589 [inline]
 SyS_write+0xef/0x220 fs/read_write.c:581
 entry_SYSCALL_64_fastpath+0x1f/0x96

Freed by task 1607:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 kasan_slab_free+0x71/0xc0 mm/kasan/kasan.c:524
 __cache_free mm/slab.c:3489 [inline]
 kfree+0xd6/0x260 mm/slab.c:3804
 skb_free_head+0x74/0xb0 net/core/skbuff.c:550
 skb_release_data+0x58c/0x790 net/core/skbuff.c:570
 skb_release_all+0x4a/0x60 net/core/skbuff.c:627
 __kfree_skb net/core/skbuff.c:641 [inline]
 consume_skb+0x153/0x490 net/core/skbuff.c:701
 skb_free_datagram+0x1a/0xe0 net/core/datagram.c:329
 netlink_recvmsg+0x5c6/0x1300 net/netlink/af_netlink.c:1976
 sock_recvmsg_nosec net/socket.c:801 [inline]
 sock_recvmsg+0xc9/0x110 net/socket.c:808
 ___sys_recvmsg+0x2a4/0x640 net/socket.c:2177
 __sys_recvmsg+0xe2/0x210 net/socket.c:2222
 SYSC_recvmsg net/socket.c:2234 [inline]
 SyS_recvmsg+0x2d/0x50 net/socket.c:2229
 entry_SYSCALL_64_fastpath+0x1f/0x96

The buggy address belongs to the object at ffff8801ce7d3a00
 which belongs to the cache kmalloc-512 of size 512
The buggy address is located 120 bytes inside of
 512-byte region [ffff8801ce7d3a00, ffff8801ce7d3c00)
The buggy address belongs to the page:
page:00000000f388711e count:1 mapcount:0 mapping:000000009914ca15 index:0x0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801ce7d3000 0000000000000000 0000000100000006
raw: ffffea000739f560 ffff8801dac01748 ffff8801dac00940 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801ce7d3900: 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
 ffff8801ce7d3980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801ce7d3a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                                                ^
 ffff8801ce7d3a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801ce7d3b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
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