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BUG: KMSAN: uninit-value in gue_err+0x514/0xfa0 net/ipv4/fou.c:1032
CPU: 1 PID: 12928 Comm: syz-executor.2 Not tainted 5.0.0+ #17
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+0x173/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x131/0x2a0 mm/kmsan/kmsan.c:624
 __msan_warning+0x7a/0xf0 mm/kmsan/kmsan_instr.c:310
 gue_err+0x514/0xfa0 net/ipv4/fou.c:1032
 __udp4_lib_err_encap_no_sk net/ipv4/udp.c:571 [inline]
 __udp4_lib_err_encap net/ipv4/udp.c:626 [inline]
 __udp4_lib_err+0x12e6/0x1d40 net/ipv4/udp.c:665
 udp_err+0x74/0x90 net/ipv4/udp.c:737
 icmp_socket_deliver net/ipv4/icmp.c:767 [inline]
 icmp_unreach+0xb65/0x1070 net/ipv4/icmp.c:884
 icmp_rcv+0x11a1/0x1950 net/ipv4/icmp.c:1066
 ip_protocol_deliver_rcu+0x584/0xbb0 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+0x624/0x7b0 net/ipv4/ip_input.c:255
 dst_input include/net/dst.h:450 [inline]
 ip_rcv_finish net/ipv4/ip_input.c:414 [inline]
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ip_rcv+0x6bd/0x740 net/ipv4/ip_input.c:524
 __netif_receive_skb_one_core net/core/dev.c:4973 [inline]
 __netif_receive_skb net/core/dev.c:5083 [inline]
 process_backlog+0x756/0x10e0 net/core/dev.c:5923
 napi_poll net/core/dev.c:6346 [inline]
 net_rx_action+0x78b/0x1a60 net/core/dev.c:6412
 __do_softirq+0x53f/0x93a kernel/softirq.c:293
 do_softirq_own_stack+0x49/0x80 arch/x86/entry/entry_64.S:1039
 </IRQ>
 do_softirq kernel/softirq.c:338 [inline]
 __local_bh_enable_ip+0x16f/0x1a0 kernel/softirq.c:190
 local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
 rcu_read_unlock_bh include/linux/rcupdate.h:696 [inline]
 ip_finish_output2+0x1627/0x1820 net/ipv4/ip_output.c:231
 ip_finish_output+0xd2b/0xfd0 net/ipv4/ip_output.c:317
 NF_HOOK_COND include/linux/netfilter.h:278 [inline]
 ip_output+0x53f/0x610 net/ipv4/ip_output.c:405
 dst_output include/net/dst.h:444 [inline]
 ip_local_out net/ipv4/ip_output.c:124 [inline]
 ip_send_skb+0x179/0x360 net/ipv4/ip_output.c:1465
 udp_send_skb+0xf25/0x18b0 net/ipv4/udp.c:901
 udp_sendmsg+0x3aa4/0x40f0 net/ipv4/udp.c:1188
 udpv6_sendmsg+0x13c1/0x4500 net/ipv6/udp.c:1289
 inet_sendmsg+0x54a/0x720 net/ipv4/af_inet.c:798
 sock_sendmsg_nosec net/socket.c:622 [inline]
 sock_sendmsg net/socket.c:632 [inline]
 ___sys_sendmsg+0xdb9/0x11b0 net/socket.c:2115
 __sys_sendmmsg+0x580/0xad0 net/socket.c:2210
 __do_sys_sendmmsg net/socket.c:2239 [inline]
 __se_sys_sendmmsg+0xbd/0xe0 net/socket.c:2236
 __x64_sys_sendmmsg+0x56/0x70 net/socket.c:2236
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x458209
Code: ad b8 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 7b b8 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f8aecbd9c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 0000000000000004 RCX: 0000000000458209
RDX: 00000000000005c3 RSI: 0000000020000240 RDI: 0000000000000005
RBP: 000000000073bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f8aecbda6d4
R13: 00000000004c513e R14: 00000000004d8ec0 R15: 00000000ffffffff

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:205 [inline]
 kmsan_internal_poison_shadow+0x92/0x150 mm/kmsan/kmsan.c:159
 kmsan_kmalloc+0xa6/0x130 mm/kmsan/kmsan_hooks.c:173
 kmsan_slab_alloc+0xe/0x10 mm/kmsan/kmsan_hooks.c:182
 slab_post_alloc_hook mm/slab.h:445 [inline]
 slab_alloc_node mm/slub.c:2773 [inline]
 __kmalloc_node_track_caller+0xe9e/0xff0 mm/slub.c:4398
 __kmalloc_reserve net/core/skbuff.c:140 [inline]
 __alloc_skb+0x309/0xa20 net/core/skbuff.c:208
 alloc_skb include/linux/skbuff.h:1012 [inline]
 alloc_skb_with_frags+0x186/0xa60 net/core/skbuff.c:5287
 sock_alloc_send_pskb+0xafd/0x10a0 net/core/sock.c:2091
 sock_alloc_send_skb+0xca/0xe0 net/core/sock.c:2108
 __ip_append_data+0x34cd/0x5000 net/ipv4/ip_output.c:998
 ip_append_data+0x324/0x480 net/ipv4/ip_output.c:1220
 icmp_push_reply+0x23d/0x7e0 net/ipv4/icmp.c:375
 __icmp_send+0x2ea3/0x30f0 net/ipv4/icmp.c:737
 icmp_send include/net/icmp.h:47 [inline]
 __udp4_lib_rcv+0x36d7/0x4b80 net/ipv4/udp.c:2323
 udp_rcv+0x5c/0x70 net/ipv4/udp.c:2482
 ip_protocol_deliver_rcu+0x584/0xbb0 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+0x624/0x7b0 net/ipv4/ip_input.c:255
 dst_input include/net/dst.h:450 [inline]
 ip_rcv_finish net/ipv4/ip_input.c:414 [inline]
 NF_HOOK include/linux/netfilter.h:289 [inline]
 ip_rcv+0x6bd/0x740 net/ipv4/ip_input.c:524
 __netif_receive_skb_one_core net/core/dev.c:4973 [inline]
 __netif_receive_skb net/core/dev.c:5083 [inline]
 process_backlog+0x756/0x10e0 net/core/dev.c:5923
 napi_poll net/core/dev.c:6346 [inline]
 net_rx_action+0x78b/0x1a60 net/core/dev.c:6412
 __do_softirq+0x53f/0x93a kernel/softirq.c:293
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