================================================================== BUG: KMSAN: uninit-value in ip_check_mc_rcu+0x2a5/0x670 net/ipv4/igmp.c:2679 CPU: 1 PID: 11692 Comm: syz-executor0 Not tainted 4.17.0+ #22 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+0x185/0x1d0 lib/dump_stack.c:113 kmsan_report+0x188/0x2a0 mm/kmsan/kmsan.c:990 __msan_warning_32+0x70/0xc0 mm/kmsan/kmsan_instr.c:640 ip_check_mc_rcu+0x2a5/0x670 net/ipv4/igmp.c:2679 __mkroute_output net/ipv4/route.c:2199 [inline] ip_route_output_key_hash_rcu+0x1f92/0x3a90 net/ipv4/route.c:2478 ip_route_output_key_hash net/ipv4/route.c:2307 [inline] __ip_route_output_key include/net/route.h:124 [inline] ip_route_output_flow+0x1d4/0x3b0 net/ipv4/route.c:2562 ip_route_output_key include/net/route.h:134 [inline] ip_tunnel_xmit+0x12d2/0x37c0 net/ipv4/ip_tunnel.c:717 __gre_xmit net/ipv4/ip_gre.c:449 [inline] ipgre_xmit+0xe16/0xef0 net/ipv4/ip_gre.c:689 __netdev_start_xmit include/linux/netdevice.h:4087 [inline] netdev_start_xmit include/linux/netdevice.h:4096 [inline] xmit_one net/core/dev.c:3053 [inline] dev_hard_start_xmit+0x5f6/0xc80 net/core/dev.c:3069 __dev_queue_xmit+0x2ad2/0x3540 net/core/dev.c:3584 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3617 packet_snd net/packet/af_packet.c:2953 [inline] packet_sendmsg+0x818b/0x8cc0 net/packet/af_packet.c:2978 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg net/socket.c:639 [inline] ___sys_sendmsg+0xec8/0x1320 net/socket.c:2117 __sys_sendmsg net/socket.c:2155 [inline] __do_sys_sendmsg net/socket.c:2164 [inline] __se_sys_sendmsg net/socket.c:2162 [inline] __x64_sys_sendmsg+0x331/0x460 net/socket.c:2162 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x63/0xe7 RIP: 0033:0x455ba9 RSP: 002b:00007f7568789c68 EFLAGS: 00000246 ORIG_RAX: 000000000000002e RAX: ffffffffffffffda RBX: 00007f756878a6d4 RCX: 0000000000455ba9 RDX: 0000000000000000 RSI: 0000000020001540 RDI: 0000000000000013 RBP: 000000000072bf48 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000004c1104 R14: 00000000004d1290 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+0x12b/0x210 mm/kmsan/kmsan.c:581 __msan_chain_origin+0x69/0xc0 mm/kmsan/kmsan_instr.c:483 ip_tunnel_init_flow include/net/ip_tunnels.h:267 [inline] ip_tunnel_xmit+0xa2e/0x37c0 net/ipv4/ip_tunnel.c:706 __gre_xmit net/ipv4/ip_gre.c:449 [inline] ipgre_xmit+0xe16/0xef0 net/ipv4/ip_gre.c:689 __netdev_start_xmit include/linux/netdevice.h:4087 [inline] netdev_start_xmit include/linux/netdevice.h:4096 [inline] xmit_one net/core/dev.c:3053 [inline] dev_hard_start_xmit+0x5f6/0xc80 net/core/dev.c:3069 __dev_queue_xmit+0x2ad2/0x3540 net/core/dev.c:3584 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3617 packet_snd net/packet/af_packet.c:2953 [inline] packet_sendmsg+0x818b/0x8cc0 net/packet/af_packet.c:2978 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg net/socket.c:639 [inline] ___sys_sendmsg+0xec8/0x1320 net/socket.c:2117 __sys_sendmsg net/socket.c:2155 [inline] __do_sys_sendmsg net/socket.c:2164 [inline] __se_sys_sendmsg net/socket.c:2162 [inline] __x64_sys_sendmsg+0x331/0x460 net/socket.c:2162 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287 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+0x12b/0x210 mm/kmsan/kmsan.c:581 kmsan_memcpy_origins+0x11d/0x170 mm/kmsan/kmsan.c:425 __msan_memcpy+0xda/0x130 mm/kmsan/kmsan_instr.c:432 pskb_expand_head+0x3a6/0x1a70 net/core/skbuff.c:1470 __skb_cow include/linux/skbuff.h:2899 [inline] skb_cow_head include/linux/skbuff.h:2933 [inline] ipgre_xmit+0x4c3/0xef0 net/ipv4/ip_gre.c:668 __netdev_start_xmit include/linux/netdevice.h:4087 [inline] netdev_start_xmit include/linux/netdevice.h:4096 [inline] xmit_one net/core/dev.c:3053 [inline] dev_hard_start_xmit+0x5f6/0xc80 net/core/dev.c:3069 __dev_queue_xmit+0x2ad2/0x3540 net/core/dev.c:3584 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3617 packet_snd net/packet/af_packet.c:2953 [inline] packet_sendmsg+0x818b/0x8cc0 net/packet/af_packet.c:2978 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg net/socket.c:639 [inline] ___sys_sendmsg+0xec8/0x1320 net/socket.c:2117 __sys_sendmsg net/socket.c:2155 [inline] __do_sys_sendmsg net/socket.c:2164 [inline] __se_sys_sendmsg net/socket.c:2162 [inline] __x64_sys_sendmsg+0x331/0x460 net/socket.c:2162 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287 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+0x94/0x100 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:2753 [inline] __kmalloc_node_track_caller+0xb35/0x11b0 mm/slub.c:4395 __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:5254 sock_alloc_send_pskb+0xb56/0x11a0 net/core/sock.c:2088 packet_alloc_skb net/packet/af_packet.c:2810 [inline] packet_snd net/packet/af_packet.c:2901 [inline] packet_sendmsg+0x6672/0x8cc0 net/packet/af_packet.c:2978 sock_sendmsg_nosec net/socket.c:629 [inline] sock_sendmsg net/socket.c:639 [inline] ___sys_sendmsg+0xec8/0x1320 net/socket.c:2117 __sys_sendmsg net/socket.c:2155 [inline] __do_sys_sendmsg net/socket.c:2164 [inline] __se_sys_sendmsg net/socket.c:2162 [inline] __x64_sys_sendmsg+0x331/0x460 net/socket.c:2162 do_syscall_64+0x15b/0x230 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x63/0xe7 ==================================================================