syzbot

==================================================================
BUG: KMSAN: uninit-value in __arch_swab32 arch/x86/include/uapi/asm/swab.h:10 [inline]
BUG: KMSAN: uninit-value in __fswab32 include/uapi/linux/swab.h:59 [inline]
BUG: KMSAN: uninit-value in fib_table_lookup+0xfb9/0x2130 net/ipv4/fib_trie.c:1323
CPU: 1 PID: 13757 Comm: syz-executor1 Not tainted 4.18.0-rc5+ #29
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x185/0x1e0 lib/dump_stack.c:113
 kmsan_report+0x195/0x2c0 mm/kmsan/kmsan.c:982
 __msan_warning+0x7d/0xe0 mm/kmsan/kmsan_instr.c:645
 __arch_swab32 arch/x86/include/uapi/asm/swab.h:10 [inline]
 __fswab32 include/uapi/linux/swab.h:59 [inline]
 fib_table_lookup+0xfb9/0x2130 net/ipv4/fib_trie.c:1323
 fib_lookup include/net/ip_fib.h:330 [inline]
 ip_route_output_key_hash_rcu+0xb0f/0x3b00 net/ipv4/route.c:2434
 ip_route_output_key_hash net/ipv4/route.c:2327 [inline]
 __ip_route_output_key include/net/route.h:124 [inline]
 ip_route_output_flow+0x1f3/0x400 net/ipv4/route.c:2582
 ip_route_output_key include/net/route.h:134 [inline]
 ip_tunnel_xmit+0x13d8/0x3b10 net/ipv4/ip_tunnel.c:717
 __gre_xmit net/ipv4/ip_gre.c:449 [inline]
 ipgre_xmit+0xe16/0xef0 net/ipv4/ip_gre.c:701
 __netdev_start_xmit include/linux/netdevice.h:4148 [inline]
 netdev_start_xmit include/linux/netdevice.h:4157 [inline]
 xmit_one net/core/dev.c:3034 [inline]
 dev_hard_start_xmit+0x60f/0xcc0 net/core/dev.c:3050
 __dev_queue_xmit+0x3060/0x3c70 net/core/dev.c:3569
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3602
 packet_snd net/packet/af_packet.c:2919 [inline]
 packet_sendmsg+0x8469/0x9010 net/packet/af_packet.c:2944
 sock_sendmsg_nosec net/socket.c:641 [inline]
 sock_sendmsg net/socket.c:651 [inline]
 __sys_sendto+0x798/0x8e0 net/socket.c:1797
 __do_sys_sendto net/socket.c:1809 [inline]
 __se_sys_sendto net/socket.c:1805 [inline]
 __x64_sys_sendto+0x1a1/0x210 net/socket.c:1805
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x455ab9
Code: 1d ba fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 eb b9 fb ff c3 66 2e 0f 1f 84 00 00 00 00 
RSP: 002b:00007f0784ccac68 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 00007f0784ccb6d4 RCX: 0000000000455ab9
RDX: 0000000000000011 RSI: 0000000020000040 RDI: 0000000000000017
RBP: 000000000072bf48 R08: 0000000020000080 R09: 000000000000001c
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004c1164 R14: 00000000004d1860 R15: 0000000000000001

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:271 [inline]
 kmsan_internal_chain_origin+0x13c/0x240 mm/kmsan/kmsan.c:573
 __msan_chain_origin+0x76/0xd0 mm/kmsan/kmsan_instr.c:483
 ip_tunnel_init_flow include/net/ip_tunnels.h:267 [inline]
 ip_tunnel_xmit+0xa9b/0x3b10 net/ipv4/ip_tunnel.c:706
 __gre_xmit net/ipv4/ip_gre.c:449 [inline]
 ipgre_xmit+0xe16/0xef0 net/ipv4/ip_gre.c:701
 __netdev_start_xmit include/linux/netdevice.h:4148 [inline]
 netdev_start_xmit include/linux/netdevice.h:4157 [inline]
 xmit_one net/core/dev.c:3034 [inline]
 dev_hard_start_xmit+0x60f/0xcc0 net/core/dev.c:3050
 __dev_queue_xmit+0x3060/0x3c70 net/core/dev.c:3569
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3602
 packet_snd net/packet/af_packet.c:2919 [inline]
 packet_sendmsg+0x8469/0x9010 net/packet/af_packet.c:2944
 sock_sendmsg_nosec net/socket.c:641 [inline]
 sock_sendmsg net/socket.c:651 [inline]
 __sys_sendto+0x798/0x8e0 net/socket.c:1797
 __do_sys_sendto net/socket.c:1809 [inline]
 __se_sys_sendto net/socket.c:1805 [inline]
 __x64_sys_sendto+0x1a1/0x210 net/socket.c:1805
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x63/0xe7

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:271 [inline]
 kmsan_internal_chain_origin+0x13c/0x240 mm/kmsan/kmsan.c:573
 kmsan_memcpy_origins+0x13d/0x1b0 mm/kmsan/kmsan.c:397
 __msan_memcpy+0xe7/0x150 mm/kmsan/kmsan_instr.c:432
 pskb_expand_head+0x3a6/0x1a70 net/core/skbuff.c:1471
 __skb_cow include/linux/skbuff.h:2902 [inline]
 skb_cow_head include/linux/skbuff.h:2936 [inline]
 ipgre_xmit+0x4c3/0xef0 net/ipv4/ip_gre.c:680
 __netdev_start_xmit include/linux/netdevice.h:4148 [inline]
 netdev_start_xmit include/linux/netdevice.h:4157 [inline]
 xmit_one net/core/dev.c:3034 [inline]
 dev_hard_start_xmit+0x60f/0xcc0 net/core/dev.c:3050
 __dev_queue_xmit+0x3060/0x3c70 net/core/dev.c:3569
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3602
 packet_snd net/packet/af_packet.c:2919 [inline]
 packet_sendmsg+0x8469/0x9010 net/packet/af_packet.c:2944
 sock_sendmsg_nosec net/socket.c:641 [inline]
 sock_sendmsg net/socket.c:651 [inline]
 __sys_sendto+0x798/0x8e0 net/socket.c:1797
 __do_sys_sendto net/socket.c:1809 [inline]
 __se_sys_sendto net/socket.c:1805 [inline]
 __x64_sys_sendto+0x1a1/0x210 net/socket.c:1805
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x63/0xe7

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:256 [inline]
 kmsan_internal_poison_shadow+0xc8/0x1d0 mm/kmsan/kmsan.c:181
 kmsan_kmalloc+0xa1/0x120 mm/kmsan/kmsan_hooks.c:91
 kmsan_slab_alloc+0x10/0x20 mm/kmsan/kmsan_hooks.c:100
 slab_post_alloc_hook mm/slab.h:446 [inline]
 slab_alloc_node mm/slub.c:2720 [inline]
 __kmalloc_node_track_caller+0xb48/0x11d0 mm/slub.c:4353
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x2cb/0x9e0 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:988 [inline]
 alloc_skb_with_frags+0x1e6/0xb80 net/core/skbuff.c:5271
 sock_alloc_send_pskb+0xb59/0x11e0 net/core/sock.c:2095
 packet_alloc_skb net/packet/af_packet.c:2776 [inline]
 packet_snd net/packet/af_packet.c:2867 [inline]
 packet_sendmsg+0x68cb/0x9010 net/packet/af_packet.c:2944
 sock_sendmsg_nosec net/socket.c:641 [inline]
 sock_sendmsg net/socket.c:651 [inline]
 __sys_sendto+0x798/0x8e0 net/socket.c:1797
 __do_sys_sendto net/socket.c:1809 [inline]
 __se_sys_sendto net/socket.c:1805 [inline]
 __x64_sys_sendto+0x1a1/0x210 net/socket.c:1805
 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
==================================================================