syzbot

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BUG: KMSAN: uninit-value in ip_check_mc_rcu+0x2a5/0x670 net/ipv4/igmp.c:2705
CPU: 0 PID: 10671 Comm: syz-executor7 Not tainted 4.19.0-rc1+ #42
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+0x14b/0x190 lib/dump_stack.c:113
 kmsan_report+0x183/0x2b0 mm/kmsan/kmsan.c:956
 __msan_warning+0x70/0xc0 mm/kmsan/kmsan_instr.c:645
 ip_check_mc_rcu+0x2a5/0x670 net/ipv4/igmp.c:2705
 __mkroute_output net/ipv4/route.c:2223 [inline]
 ip_route_output_key_hash_rcu+0x1f2a/0x3aa0 net/ipv4/route.c:2502
 ip_route_output_key_hash net/ipv4/route.c:2331 [inline]
 __ip_route_output_key include/net/route.h:124 [inline]
 ip_route_output_flow+0x1d2/0x3a0 net/ipv4/route.c:2586
 ip_route_output_key include/net/route.h:134 [inline]
 ip_tunnel_xmit+0x128c/0x3750 net/ipv4/ip_tunnel.c:717
 __gre_xmit net/ipv4/ip_gre.c:449 [inline]
 ipgre_xmit+0xdcf/0xeb0 net/ipv4/ip_gre.c:703
 __netdev_start_xmit include/linux/netdevice.h:4287 [inline]
 netdev_start_xmit include/linux/netdevice.h:4296 [inline]
 xmit_one net/core/dev.c:3217 [inline]
 dev_hard_start_xmit+0x5df/0xc20 net/core/dev.c:3233
 __dev_queue_xmit+0x2f35/0x3ab0 net/core/dev.c:3803
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3836
 packet_snd net/packet/af_packet.c:2925 [inline]
 packet_sendmsg+0x80ff/0x8c60 net/packet/af_packet.c:2950
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 ___sys_sendmsg+0xe70/0x1290 net/socket.c:2114
 __sys_sendmsg net/socket.c:2152 [inline]
 __do_sys_sendmsg net/socket.c:2161 [inline]
 __se_sys_sendmsg+0x2a3/0x3d0 net/socket.c:2159
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2159
 do_syscall_64+0xb8/0x100 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x457099
Code: fd b4 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 cb b4 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f53cc0d9c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007f53cc0da6d4 RCX: 0000000000457099
RDX: 0000000000000000 RSI: 00000000200001c0 RDI: 0000000000000003
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004d4b30 R14: 00000000004c90b1 R15: 0000000000000000

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+0x128/0x210 mm/kmsan/kmsan.c:573
 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:482
 ip_tunnel_init_flow include/net/ip_tunnels.h:267 [inline]
 ip_tunnel_xmit+0xa24/0x3750 net/ipv4/ip_tunnel.c:706
 __gre_xmit net/ipv4/ip_gre.c:449 [inline]
 ipgre_xmit+0xdcf/0xeb0 net/ipv4/ip_gre.c:703
 __netdev_start_xmit include/linux/netdevice.h:4287 [inline]
 netdev_start_xmit include/linux/netdevice.h:4296 [inline]
 xmit_one net/core/dev.c:3217 [inline]
 dev_hard_start_xmit+0x5df/0xc20 net/core/dev.c:3233
 __dev_queue_xmit+0x2f35/0x3ab0 net/core/dev.c:3803
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3836
 packet_snd net/packet/af_packet.c:2925 [inline]
 packet_sendmsg+0x80ff/0x8c60 net/packet/af_packet.c:2950
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 ___sys_sendmsg+0xe70/0x1290 net/socket.c:2114
 __sys_sendmsg net/socket.c:2152 [inline]
 __do_sys_sendmsg net/socket.c:2161 [inline]
 __se_sys_sendmsg+0x2a3/0x3d0 net/socket.c:2159
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2159
 do_syscall_64+0xb8/0x100 arch/x86/entry/common.c:291
 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+0x128/0x210 mm/kmsan/kmsan.c:573
 kmsan_memcpy_origins+0x13d/0x1b0 mm/kmsan/kmsan.c:397
 __msan_memcpy+0xc3/0x130 mm/kmsan/kmsan_instr.c:431
 pskb_expand_head+0x3b3/0x19c0 net/core/skbuff.c:1473
 __skb_cow include/linux/skbuff.h:2911 [inline]
 skb_cow_head include/linux/skbuff.h:2945 [inline]
 ipgre_xmit+0x4bc/0xeb0 net/ipv4/ip_gre.c:682
 __netdev_start_xmit include/linux/netdevice.h:4287 [inline]
 netdev_start_xmit include/linux/netdevice.h:4296 [inline]
 xmit_one net/core/dev.c:3217 [inline]
 dev_hard_start_xmit+0x5df/0xc20 net/core/dev.c:3233
 __dev_queue_xmit+0x2f35/0x3ab0 net/core/dev.c:3803
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3836
 packet_snd net/packet/af_packet.c:2925 [inline]
 packet_sendmsg+0x80ff/0x8c60 net/packet/af_packet.c:2950
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 ___sys_sendmsg+0xe70/0x1290 net/socket.c:2114
 __sys_sendmsg net/socket.c:2152 [inline]
 __do_sys_sendmsg net/socket.c:2161 [inline]
 __se_sys_sendmsg+0x2a3/0x3d0 net/socket.c:2159
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2159
 do_syscall_64+0xb8/0x100 arch/x86/entry/common.c:291
 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+0xb8/0x1b0 mm/kmsan/kmsan.c:181
 kmsan_kmalloc+0x98/0x100 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:2719 [inline]
 __kmalloc_node_track_caller+0x9e7/0x1160 mm/slub.c:4352
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x2f5/0x9e0 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:996 [inline]
 alloc_skb_with_frags+0x1d0/0xac0 net/core/skbuff.c:5276
 sock_alloc_send_pskb+0xb47/0x1170 net/core/sock.c:2082
 packet_alloc_skb net/packet/af_packet.c:2779 [inline]
 packet_snd net/packet/af_packet.c:2870 [inline]
 packet_sendmsg+0x6599/0x8c60 net/packet/af_packet.c:2950
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 ___sys_sendmsg+0xe70/0x1290 net/socket.c:2114
 __sys_sendmsg net/socket.c:2152 [inline]
 __do_sys_sendmsg net/socket.c:2161 [inline]
 __se_sys_sendmsg+0x2a3/0x3d0 net/socket.c:2159
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2159
 do_syscall_64+0xb8/0x100 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
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