ip6_tunnel:  xmit: Local address not yet configured! ip6_tunnel: } xmit: Local address not yet configured! ip6_tunnel: w xmit: Local address not yet configured! ================================================================== BUG: KASAN: use-after-free in tcp_skb_pcount include/net/tcp.h:912 [inline] BUG: KASAN: use-after-free in tcp_init_tso_segs+0x19d/0x1f0 net/ipv4/tcp_output.c:1790 Read of size 2 at addr ffff8881d4f76530 by task syz-executor.2/1514 CPU: 1 PID: 1514 Comm: syz-executor.2 Not tainted 4.14.145+ #0 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0xca/0x134 lib/dump_stack.c:53 print_address_description+0x60/0x226 mm/kasan/report.c:187 __kasan_report.cold+0x1a/0x41 mm/kasan/report.c:316 tcp_skb_pcount include/net/tcp.h:912 [inline] tcp_init_tso_segs+0x19d/0x1f0 net/ipv4/tcp_output.c:1790 tcp_write_xmit+0x15a/0x4730 net/ipv4/tcp_output.c:2330 __tcp_push_pending_frames+0xa0/0x230 net/ipv4/tcp_output.c:2563 tcp_push+0x402/0x600 net/ipv4/tcp.c:715 tcp_sendmsg_locked+0x1258/0x2f50 net/ipv4/tcp.c:1413 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1457 inet_sendmsg+0x15b/0x520 net/ipv4/af_inet.c:760 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb7/0x100 net/socket.c:656 SYSC_sendto net/socket.c:1763 [inline] SyS_sendto+0x1de/0x2f0 net/socket.c:1731 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 RIP: 0033:0x459a09 RSP: 002b:00007f980fde7c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000459a09 RDX: 000000000000fe6a RSI: 00000000200012c0 RDI: 0000000000000003 RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000027 R10: 0000000000000011 R11: 0000000000000246 R12: 00007f980fde86d4 R13: 00000000004c79ac R14: 00000000004dd400 R15: 00000000ffffffff Allocated by task 1514: save_stack mm/kasan/common.c:76 [inline] set_track mm/kasan/common.c:85 [inline] __kasan_kmalloc.part.0+0x53/0xc0 mm/kasan/common.c:495 slab_post_alloc_hook mm/slab.h:439 [inline] slab_alloc_node mm/slub.c:2792 [inline] slab_alloc mm/slub.c:2800 [inline] kmem_cache_alloc+0xee/0x360 mm/slub.c:2805 kmem_cache_alloc_node include/linux/slab.h:361 [inline] __alloc_skb+0xea/0x5c0 net/core/skbuff.c:193 alloc_skb_fclone include/linux/skbuff.h:1022 [inline] sk_stream_alloc_skb+0xf4/0x8a0 net/ipv4/tcp.c:855 tcp_sendmsg_locked+0xf11/0x2f50 net/ipv4/tcp.c:1301 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1457 inet_sendmsg+0x15b/0x520 net/ipv4/af_inet.c:760 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb7/0x100 net/socket.c:656 ___sys_sendmsg+0x368/0x890 net/socket.c:2062 __sys_sendmmsg+0x13c/0x360 net/socket.c:2152 SYSC_sendmmsg net/socket.c:2183 [inline] SyS_sendmmsg+0x2f/0x50 net/socket.c:2178 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 0xffffffffffffffff Freed by task 1514: save_stack mm/kasan/common.c:76 [inline] set_track mm/kasan/common.c:85 [inline] __kasan_slab_free+0x164/0x210 mm/kasan/common.c:457 slab_free_hook mm/slub.c:1407 [inline] slab_free_freelist_hook mm/slub.c:1458 [inline] slab_free mm/slub.c:3039 [inline] kmem_cache_free+0xd7/0x3b0 mm/slub.c:3055 kfree_skbmem+0x84/0x110 net/core/skbuff.c:607 sk_wmem_free_skb include/net/sock.h:1416 [inline] tcp_remove_empty_skb net/ipv4/tcp.c:929 [inline] tcp_remove_empty_skb+0x264/0x320 net/ipv4/tcp.c:923 tcp_sendmsg_locked+0x1c09/0x2f50 net/ipv4/tcp.c:1435 tcp_sendmsg+0x2b/0x40 net/ipv4/tcp.c:1457 inet_sendmsg+0x15b/0x520 net/ipv4/af_inet.c:760 sock_sendmsg_nosec net/socket.c:646 [inline] sock_sendmsg+0xb7/0x100 net/socket.c:656 ___sys_sendmsg+0x368/0x890 net/socket.c:2062 __sys_sendmmsg+0x13c/0x360 net/socket.c:2152 SYSC_sendmmsg net/socket.c:2183 [inline] SyS_sendmmsg+0x2f/0x50 net/socket.c:2178 do_syscall_64+0x19b/0x520 arch/x86/entry/common.c:292 entry_SYSCALL_64_after_hwframe+0x42/0xb7 0xffffffffffffffff The buggy address belongs to the object at ffff8881d4f76500 which belongs to the cache skbuff_fclone_cache of size 456 The buggy address is located 48 bytes inside of 456-byte region [ffff8881d4f76500, ffff8881d4f766c8) The buggy address belongs to the page: page:ffffea000753dd80 count:1 mapcount:0 mapping: (null) index:0x0 compound_mapcount: 0 flags: 0x4000000000010200(slab|head) raw: 4000000000010200 0000000000000000 0000000000000000 00000001000c000c raw: ffffea0005e69d80 0000000600000004 ffff8881dab70400 0000000000000000 page dumped because: kasan: bad access detected Memory state around the buggy address: ffff8881d4f76400: 00 00 00 00 00 00 00 00 00 fc fc fc fc fc fc fc ffff8881d4f76480: fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc fc >ffff8881d4f76500: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ^ ffff8881d4f76580: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ffff8881d4f76600: fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb fb ==================================================================