syzbot

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BUG: KMSAN: uninit-value in br_validate_ipv4+0x5d3/0xa20 net/bridge/br_netfilter_hooks.c:217
CPU: 0 PID: 30953 Comm: syz-executor3 Not tainted 4.20.0-rc2+ #88
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x32d/0x480 lib/dump_stack.c:113
 kmsan_report+0x19f/0x300 mm/kmsan/kmsan.c:911
 __msan_warning+0x76/0xc0 mm/kmsan/kmsan_instr.c:415
 br_validate_ipv4+0x5d3/0xa20 net/bridge/br_netfilter_hooks.c:217
 br_nf_pre_routing+0x1052/0x1ba0 net/bridge/br_netfilter_hooks.c:506
 nf_hook_entry_hookfn include/linux/netfilter.h:119 [inline]
 nf_hook_slow+0x15c/0x3d0 net/netfilter/core.c:511
 nf_hook include/linux/netfilter.h:244 [inline]
 NF_HOOK include/linux/netfilter.h:287 [inline]
 br_handle_frame+0xcca/0x1f10 net/bridge/br_input.c:303
 __netif_receive_skb_core+0x2124/0x56e0 net/core/dev.c:4870
 __netif_receive_skb_one_core net/core/dev.c:4939 [inline]
 __netif_receive_skb net/core/dev.c:5051 [inline]
 process_backlog+0x74a/0x11e0 net/core/dev.c:5855
 napi_poll net/core/dev.c:6275 [inline]
 net_rx_action+0x98f/0x1d50 net/core/dev.c:6341
 __do_softirq+0x721/0xc7f kernel/softirq.c:292
 do_softirq_own_stack+0x49/0x80 arch/x86/entry/entry_64.S:1031
 </IRQ>
 do_softirq kernel/softirq.c:337 [inline]
 __local_bh_enable_ip+0x228/0x260 kernel/softirq.c:189
 local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
 rcu_read_unlock_bh include/linux/rcupdate.h:696 [inline]
 __dev_queue_xmit+0x3879/0x3e00 net/core/dev.c:3865
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3871
 packet_snd net/packet/af_packet.c:2928 [inline]
 packet_sendmsg+0x797f/0x9180 net/packet/af_packet.c:2953
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 ___sys_sendmsg+0xe3b/0x1240 net/socket.c:2116
 __sys_sendmsg net/socket.c:2154 [inline]
 __do_sys_sendmsg net/socket.c:2163 [inline]
 __se_sys_sendmsg+0x305/0x460 net/socket.c:2161
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2161
 do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x457569
Code: fd b3 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 b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f23916c9c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457569
RDX: 0000000000000000 RSI: 0000000020000000 RDI: 0000000000000003
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f23916ca6d4
R13: 00000000004c3b1f R14: 00000000004d5d00 R15: 00000000ffffffff

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:252 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:267 [inline]
 kmsan_internal_chain_origin+0x136/0x240 mm/kmsan/kmsan.c:569
 kmsan_memcpy_origins+0x13d/0x190 mm/kmsan/kmsan.c:393
 __msan_memcpy+0x6f/0x80 mm/kmsan/kmsan_instr.c:242
 pskb_expand_head+0x436/0x1d20 net/core/skbuff.c:1470
 __skb_cow include/linux/skbuff.h:2948 [inline]
 skb_cow_head include/linux/skbuff.h:2982 [inline]
 ip_tunnel_xmit+0x35a3/0x3d90 net/ipv4/ip_tunnel.c:780
 __gre_xmit net/ipv4/ip_gre.c:451 [inline]
 ipgre_xmit+0xef7/0x1000 net/ipv4/ip_gre.c:705
 __netdev_start_xmit include/linux/netdevice.h:4356 [inline]
 netdev_start_xmit include/linux/netdevice.h:4365 [inline]
 xmit_one net/core/dev.c:3252 [inline]
 dev_hard_start_xmit+0x6dc/0xde0 net/core/dev.c:3268
 __dev_queue_xmit+0x2d9e/0x3e00 net/core/dev.c:3838
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3871
 packet_snd net/packet/af_packet.c:2928 [inline]
 packet_sendmsg+0x797f/0x9180 net/packet/af_packet.c:2953
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 ___sys_sendmsg+0xe3b/0x1240 net/socket.c:2116
 __sys_sendmsg net/socket.c:2154 [inline]
 __do_sys_sendmsg net/socket.c:2163 [inline]
 __se_sys_sendmsg+0x305/0x460 net/socket.c:2161
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2161
 do_syscall_64+0xcf/0x110 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:252 [inline]
 kmsan_internal_poison_shadow+0xc8/0x1c0 mm/kmsan/kmsan.c:177
 kmsan_kmalloc+0x98/0xf0 mm/kmsan/kmsan_hooks.c:104
 kmsan_slab_alloc+0xe/0x10 mm/kmsan/kmsan_hooks.c:113
 slab_post_alloc_hook mm/slab.h:446 [inline]
 slab_alloc_node mm/slub.c:2765 [inline]
 __kmalloc_node_track_caller+0xf62/0x14e0 mm/slub.c:4396
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x42b/0xeb0 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:998 [inline]
 alloc_skb_with_frags+0x1c9/0xa80 net/core/skbuff.c:5220
 sock_alloc_send_pskb+0xeb3/0x14c0 net/core/sock.c:2083
 packet_alloc_skb net/packet/af_packet.c:2781 [inline]
 packet_snd net/packet/af_packet.c:2872 [inline]
 packet_sendmsg+0x6719/0x9180 net/packet/af_packet.c:2953
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 ___sys_sendmsg+0xe3b/0x1240 net/socket.c:2116
 __sys_sendmsg net/socket.c:2154 [inline]
 __do_sys_sendmsg net/socket.c:2163 [inline]
 __se_sys_sendmsg+0x305/0x460 net/socket.c:2161
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2161
 do_syscall_64+0xcf/0x110 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
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