==================================================================
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 gre_parse_header+0x1395/0x1690 net/ipv4/gre_demux.c:136
CPU: 1 PID: 10615 Comm: syz-executor.0 Not tainted 5.1.0+ #1
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+0x191/0x1f0 lib/dump_stack.c:113
 kmsan_report+0x130/0x2a0 mm/kmsan/kmsan.c:622
 __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:310
 __arch_swab32 arch/x86/include/uapi/asm/swab.h:10 [inline]
 __fswab32 include/uapi/linux/swab.h:59 [inline]
 gre_parse_header+0x1395/0x1690 net/ipv4/gre_demux.c:136
 gre_rcv+0x1ee/0x18b0 net/ipv4/ip_gre.c:414
 gre_rcv+0x2dd/0x3c0 net/ipv4/gre_demux.c:160
 ip_protocol_deliver_rcu+0x504/0xad0 net/ipv4/ip_input.c:208
 ip_local_deliver_finish net/ipv4/ip_input.c:234 [inline]
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ip_local_deliver+0x628/0x7b0 net/ipv4/ip_input.c:255
 dst_input include/net/dst.h:450 [inline]
 ip_rcv_finish net/ipv4/ip_input.c:413 [inline]
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ip_rcv+0x6c5/0x740 net/ipv4/ip_input.c:523
 __netif_receive_skb_one_core net/core/dev.c:4987 [inline]
 __netif_receive_skb net/core/dev.c:5099 [inline]
 process_backlog+0x6da/0x1070 net/core/dev.c:5939
 napi_poll net/core/dev.c:6362 [inline]
 net_rx_action+0x738/0x1940 net/core/dev.c:6428
 __do_softirq+0x4ad/0x858 kernel/softirq.c:294
 do_softirq_own_stack+0x49/0x80 arch/x86/entry/entry_64.S:1039
 </IRQ>
 do_softirq kernel/softirq.c:339 [inline]
 __local_bh_enable_ip+0x199/0x1e0 kernel/softirq.c:191
 local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
 rcu_read_unlock_bh include/linux/rcupdate.h:684 [inline]
 ip_finish_output2+0x1721/0x1930 net/ipv4/ip_output.c:231
 ip_finish_output+0xd2a/0xfd0 net/ipv4/ip_output.c:317
 NF_HOOK_COND include/linux/netfilter.h:278 [inline]
 ip_output+0x541/0x610 net/ipv4/ip_output.c:405
 dst_output include/net/dst.h:444 [inline]
 NF_HOOK include/linux/netfilter.h:289 [inline]
 raw_send_hdrinc net/ipv4/raw.c:432 [inline]
 raw_sendmsg+0x41dc/0x4670 net/ipv4/raw.c:663
 inet_sendmsg+0x546/0x720 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:661 [inline]
 __sys_sendto+0x8cf/0xad0 net/socket.c:1932
 __do_sys_sendto net/socket.c:1944 [inline]
 __se_sys_sendto+0x107/0x130 net/socket.c:1940
 __x64_sys_sendto+0x6e/0x90 net/socket.c:1940
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x459279
Code: fd b7 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 b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007ffeb5502558 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 0000000000000006 RCX: 0000000000459279
RDX: 00000000000005aa RSI: 00000000200000c0 RDI: 0000000000000003
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000120
R10: 0000000000000000 R11: 0000000000000246 R12: 000000000188e914
R13: 00000000004c6dc9 R14: 00000000004dbcc8 R15: 00000000ffffffff

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:208 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:223 [inline]
 kmsan_internal_chain_origin+0x133/0x230 mm/kmsan/kmsan.c:429
 kmsan_memcpy_memmove_metadata+0x969/0xd40 mm/kmsan/kmsan.c:307
 kmsan_memcpy_metadata+0xb/0x10 mm/kmsan/kmsan.c:327
 __msan_memcpy+0x56/0x70 mm/kmsan/kmsan_instr.c:139
 pskb_expand_head+0x3aa/0x1a30 net/core/skbuff.c:1478
 __skb_cow include/linux/skbuff.h:3029 [inline]
 skb_cow_head include/linux/skbuff.h:3063 [inline]
 ip_tunnel_xmit+0x2bd5/0x3290 net/ipv4/ip_tunnel.c:824
 __gre_xmit net/ipv4/ip_gre.c:449 [inline]
 erspan_xmit+0x1efe/0x35a0 net/ipv4/ip_gre.c:684
 __netdev_start_xmit include/linux/netdevice.h:4414 [inline]
 netdev_start_xmit include/linux/netdevice.h:4423 [inline]
 xmit_one net/core/dev.c:3292 [inline]
 dev_hard_start_xmit+0x594/0xb20 net/core/dev.c:3308
 sch_direct_xmit+0x571/0x870 net/sched/sch_generic.c:328
 qdisc_restart net/sched/sch_generic.c:391 [inline]
 __qdisc_run+0x158b/0x3380 net/sched/sch_generic.c:399
 qdisc_run include/net/pkt_sched.h:121 [inline]
 __dev_xmit_skb net/core/dev.c:3487 [inline]
 __dev_queue_xmit+0x21a0/0x3b60 net/core/dev.c:3846
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3911
 neigh_resolve_output+0xab7/0xb50 net/core/neighbour.c:1487
 neigh_output include/net/neighbour.h:508 [inline]
 ip_finish_output2+0x1709/0x1930 net/ipv4/ip_output.c:229
 ip_finish_output+0xd2a/0xfd0 net/ipv4/ip_output.c:317
 NF_HOOK_COND include/linux/netfilter.h:278 [inline]
 ip_output+0x541/0x610 net/ipv4/ip_output.c:405
 dst_output include/net/dst.h:444 [inline]
 NF_HOOK include/linux/netfilter.h:289 [inline]
 raw_send_hdrinc net/ipv4/raw.c:432 [inline]
 raw_sendmsg+0x41dc/0x4670 net/ipv4/raw.c:663
 inet_sendmsg+0x546/0x720 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:661 [inline]
 __sys_sendto+0x8cf/0xad0 net/socket.c:1932
 __do_sys_sendto net/socket.c:1944 [inline]
 __se_sys_sendto+0x107/0x130 net/socket.c:1940
 __x64_sys_sendto+0x6e/0x90 net/socket.c:1940
 do_syscall_64+0xbc/0xf0 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:208 [inline]
 kmsan_internal_poison_shadow+0x92/0x150 mm/kmsan/kmsan.c:162
 kmsan_kmalloc+0xa4/0x130 mm/kmsan/kmsan_hooks.c:175
 kmsan_slab_alloc+0xe/0x10 mm/kmsan/kmsan_hooks.c:184
 slab_post_alloc_hook mm/slab.h:442 [inline]
 slab_alloc_node mm/slub.c:2771 [inline]
 __kmalloc_node_track_caller+0xcba/0xf30 mm/slub.c:4399
 __kmalloc_reserve net/core/skbuff.c:140 [inline]
 __alloc_skb+0x306/0xa10 net/core/skbuff.c:208
 alloc_skb include/linux/skbuff.h:1059 [inline]
 alloc_skb_with_frags+0x18c/0xa80 net/core/skbuff.c:5295
 sock_alloc_send_pskb+0xafd/0x10a0 net/core/sock.c:2220
 sock_alloc_send_skb+0xca/0xe0 net/core/sock.c:2237
 raw_send_hdrinc net/ipv4/raw.c:374 [inline]
 raw_sendmsg+0x238f/0x4670 net/ipv4/raw.c:663
 inet_sendmsg+0x546/0x720 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:661 [inline]
 __sys_sendto+0x8cf/0xad0 net/socket.c:1932
 __do_sys_sendto net/socket.c:1944 [inline]
 __se_sys_sendto+0x107/0x130 net/socket.c:1940
 __x64_sys_sendto+0x6e/0x90 net/socket.c:1940
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
==================================================================