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IPv6: ADDRCONF(NETDEV_UP): veth1: link is not ready
IPv6: ADDRCONF(NETDEV_CHANGE): veth1: link becomes ready
ip (4106) used greatest stack depth: 23544 bytes left
IPv6: ADDRCONF(NETDEV_CHANGE): veth0: link becomes ready
==================================================================
BUG: KASAN: use-after-free in tcp_connect+0x2633/0x2fa0 net/ipv4/tcp_output.c:3401
Read of size 4 at addr ffff8801da394a28 by task syz-executor787/4171

CPU: 0 PID: 4171 Comm: syz-executor787 Not tainted 4.9.107-g42a730a #48
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
 ffff8801d6c47930 ffffffff81eb42a9 ffffea000768e500 ffff8801da394a28
 0000000000000000 ffff8801da394a28 ffff8801b87b9c18 ffff8801d6c47968
 ffffffff81567f09 ffff8801da394a28 0000000000000004 0000000000000000
Call Trace:
 [<ffffffff81eb42a9>] __dump_stack lib/dump_stack.c:15 [inline]
 [<ffffffff81eb42a9>] dump_stack+0xc1/0x128 lib/dump_stack.c:51
 [<ffffffff81567f09>] print_address_description+0x6c/0x234 mm/kasan/report.c:256
 [<ffffffff81568313>] kasan_report_error mm/kasan/report.c:355 [inline]
 [<ffffffff81568313>] kasan_report.cold.6+0x242/0x2fe mm/kasan/report.c:412
 [<ffffffff8153bf44>] __asan_report_load4_noabort+0x14/0x20 mm/kasan/report.c:432
 [<ffffffff833ae1f3>] tcp_connect+0x2633/0x2fa0 net/ipv4/tcp_output.c:3401
 [<ffffffff833c3e60>] tcp_v4_connect+0x19f0/0x1c20 net/ipv4/tcp_ipv4.c:250
 [<ffffffff83422980>] __inet_stream_connect+0x6e0/0xbf0 net/ipv4/af_inet.c:627
 [<ffffffff83422ee5>] inet_stream_connect+0x55/0xa0 net/ipv4/af_inet.c:691
 [<ffffffff83017958>] SYSC_connect+0x1b8/0x300 net/socket.c:1562
 [<ffffffff8301a224>] SyS_connect+0x24/0x30 net/socket.c:1543
 [<ffffffff81006316>] do_syscall_64+0x1a6/0x490 arch/x86/entry/common.c:282
 [<ffffffff839f9b13>] entry_SYSCALL_64_after_swapgs+0x5d/0xdb

Allocated by task 4171:
 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]
 kmem_cache_alloc+0xbe/0x290 mm/slub.c:2728
 kmem_cache_alloc_node include/linux/slab.h:364 [inline]
 __alloc_skb+0xe6/0x600 net/core/skbuff.c:219
 alloc_skb_fclone include/linux/skbuff.h:961 [inline]
 sk_stream_alloc_skb+0xa3/0x5d0 net/ipv4/tcp.c:828
 tcp_sendmsg+0xe57/0x3040 net/ipv4/tcp.c:1230
 inet_sendmsg+0x203/0x4d0 net/ipv4/af_inet.c:770
 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 4171:
 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]
 kmem_cache_free+0xbe/0x310 mm/slub.c:2980
 kfree_skbmem+0x7c/0x100 net/core/skbuff.c:644
 __kfree_skb+0x1d/0x20 net/core/skbuff.c:685
 sk_wmem_free_skb include/net/sock.h:1358 [inline]
 tcp_write_queue_purge include/net/tcp.h:1530 [inline]
 tcp_connect_init net/ipv4/tcp_output.c:3241 [inline]
 tcp_connect+0xaaf/0x2fa0 net/ipv4/tcp_output.c:3372
 tcp_v4_connect+0x19f0/0x1c20 net/ipv4/tcp_ipv4.c:250
 __inet_stream_connect+0x6e0/0xbf0 net/ipv4/af_inet.c:627
 inet_stream_connect+0x55/0xa0 net/ipv4/af_inet.c:691
 SYSC_connect+0x1b8/0x300 net/socket.c:1562
 SyS_connect+0x24/0x30 net/socket.c:1543
 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 ffff8801da394a00
 which belongs to the cache skbuff_fclone_cache of size 456
The buggy address is located 40 bytes inside of
 456-byte region [ffff8801da394a00, ffff8801da394bc8)
The buggy address belongs to the page:
page:ffffea000768e500 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:
 ffff8801da394900: fb fb fb fb fb fb fb fb fb fc fc fc fc fc fc fc
 ffff8801da394980: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc
>ffff8801da394a00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
                                  ^
 ffff8801da394a80: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
 ffff8801da394b00: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb
==================================================================