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BUG: KMSAN: uninit-value in __ipv6_prefix_equal64_half include/net/ipv6.h:535 [inline]
BUG: KMSAN: uninit-value in ipv6_prefix_equal include/net/ipv6.h:552 [inline]
BUG: KMSAN: uninit-value in check_6rd net/ipv6/sit.c:771 [inline]
BUG: KMSAN: uninit-value in try_6rd net/ipv6/sit.c:805 [inline]
BUG: KMSAN: uninit-value in ipip6_tunnel_xmit net/ipv6/sit.c:865 [inline]
BUG: KMSAN: uninit-value in sit_tunnel_xmit+0x191a/0x3690 net/ipv6/sit.c:1029
CPU: 0 PID: 9522 Comm: syz-executor3 Not tainted 4.19.0-rc1+ #39
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
 __ipv6_prefix_equal64_half include/net/ipv6.h:535 [inline]
 ipv6_prefix_equal include/net/ipv6.h:552 [inline]
 check_6rd net/ipv6/sit.c:771 [inline]
 try_6rd net/ipv6/sit.c:805 [inline]
 ipip6_tunnel_xmit net/ipv6/sit.c:865 [inline]
 sit_tunnel_xmit+0x191a/0x3690 net/ipv6/sit.c:1029
 __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 net/socket.c:2159 [inline]
 __x64_sys_sendmsg+0x32d/0x460 net/socket.c:2159
 do_syscall_64+0x15b/0x220 arch/x86/entry/common.c:290
 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:00007fce2b30ac78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 00007fce2b30b6d4 RCX: 0000000000457099
RDX: 0000000000000000 RSI: 0000000020000140 RDI: 0000000000000003
RBP: 00000000009300a0 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000004d47d0 R14: 00000000004c8e63 R15: 0000000000000000

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 net/socket.c:2159 [inline]
 __x64_sys_sendmsg+0x32d/0x460 net/socket.c:2159
 do_syscall_64+0x15b/0x220 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
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