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:3171 [inline]
BUG: KASAN: use-after-free in __dev_queue_xmit+0x297c/0x2b50 net/core/dev.c:3477
Read of size 2 at addr ffff8801d1b20418 by task syz-executor1/13007

CPU: 1 PID: 13007 Comm: syz-executor1 Not tainted 4.15.0-rc6-mm1+ #52
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:256
 kasan_report_error mm/kasan/report.c:354 [inline]
 kasan_report+0x23b/0x360 mm/kasan/report.c:412
 __asan_report_load2_noabort+0x14/0x20 mm/kasan/report.c:431
 __tcp_hdrlen include/linux/tcp.h:35 [inline]
 tcp_hdrlen include/linux/tcp.h:40 [inline]
 qdisc_pkt_len_init net/core/dev.c:3171 [inline]
 __dev_queue_xmit+0x297c/0x2b50 net/core/dev.c:3477
 dev_queue_xmit+0x17/0x20 net/core/dev.c:3566
 packet_snd net/packet/af_packet.c:2944 [inline]
 packet_sendmsg+0x3aed/0x60b0 net/packet/af_packet.c:2969
 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:1775 [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+0x23/0x9a
RIP: 0033:0x452ac9
RSP: 002b:00007f554a3c4c58 EFLAGS: 00000212 ORIG_RAX: 0000000000000001
RAX: ffffffffffffffda RBX: 000000000071bea0 RCX: 0000000000452ac9
RDX: 0000000000000049 RSI: 000000002046d000 RDI: 0000000000000015
RBP: 00000000000002f3 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000212 R12: 00000000006f2768
R13: 00000000ffffffff R14: 00007f554a3c56d4 R15: 0000000000000000

Allocated by task 3739:
 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:552
 kasan_slab_alloc+0x12/0x20 mm/kasan/kasan.c:489
 kmem_cache_alloc+0x12e/0x760 mm/slab.c:3541
 dup_mmap kernel/fork.c:451 [inline]
 dup_mm kernel/fork.c:1244 [inline]
 copy_mm+0x8d7/0x131f kernel/fork.c:1298
 copy_process.part.37+0x1f56/0x4b60 kernel/fork.c:1806
 copy_process kernel/fork.c:1619 [inline]
 _do_fork+0x1f7/0xf70 kernel/fork.c:2100
 SYSC_clone kernel/fork.c:2208 [inline]
 SyS_clone+0x37/0x50 kernel/fork.c:2202
 do_syscall_64+0x273/0x920 arch/x86/entry/common.c:285
 return_from_SYSCALL_64+0x0/0x75

Freed by task 10921:
 save_stack+0x43/0xd0 mm/kasan/kasan.c:447
 set_track mm/kasan/kasan.c:459 [inline]
 __kasan_slab_free+0x11a/0x170 mm/kasan/kasan.c:520
 kasan_slab_free+0xe/0x10 mm/kasan/kasan.c:527
 __cache_free mm/slab.c:3485 [inline]
 kmem_cache_free+0x86/0x2b0 mm/slab.c:3743
 remove_vma+0x162/0x1b0 mm/mmap.c:176
 exit_mmap+0x311/0x500 mm/mmap.c:3060
 __mmput kernel/fork.c:971 [inline]
 mmput+0x223/0x6c0 kernel/fork.c:992
 exit_mm kernel/exit.c:544 [inline]
 do_exit+0x90a/0x1ad0 kernel/exit.c:856
 do_group_exit+0x149/0x400 kernel/exit.c:972
 SYSC_exit_group kernel/exit.c:983 [inline]
 SyS_exit_group+0x1d/0x20 kernel/exit.c:981
 entry_SYSCALL_64_fastpath+0x23/0x9a

The buggy address belongs to the object at ffff8801d1b20358
 which belongs to the cache vm_area_struct of size 200
The buggy address is located 192 bytes inside of
 200-byte region [ffff8801d1b20358, ffff8801d1b20420)
The buggy address belongs to the page:
page:ffffea000746c800 count:1 mapcount:0 mapping:ffff8801d1b20040 index:0xffff8801d1b20ca0
flags: 0x2fffc0000000100(slab)
raw: 02fffc0000000100 ffff8801d1b20040 ffff8801d1b20ca0 000000010000000d
raw: ffffea000751c0e0 ffffea000746d6e0 ffff8801dae27840 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff8801d1b20300: fb fb fb fc fc fc fc fc fc fc fc fb fb fb fb fb
 ffff8801d1b20380: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
>ffff8801d1b20400: fb fb fb fb fc fc fc fc fc fc fc fc fb fb fb fb
                            ^
 ffff8801d1b20480: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801d1b20500: fb fb fb fb fb fc fc fc fc fc fc fc fc fb fb fb
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