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BUG: KMSAN: uninit-value in ip_tunnel_xmit+0x585/0x3a40 net/ipv4/ip_tunnel.c:663
CPU: 1 PID: 805 Comm: syz-executor.5 Not tainted 5.9.0-rc8-syzkaller #0
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+0x21c/0x280 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:122
 __msan_warning+0x5f/0xa0 mm/kmsan/kmsan_instr.c:201
 ip_tunnel_xmit+0x585/0x3a40 net/ipv4/ip_tunnel.c:663
 __gre_xmit net/ipv4/ip_gre.c:466 [inline]
 ipgre_xmit+0x1261/0x1380 net/ipv4/ip_gre.c:650
 __netdev_start_xmit include/linux/netdevice.h:4636 [inline]
 netdev_start_xmit include/linux/netdevice.h:4650 [inline]
 xmit_one+0x1fc/0x760 net/core/dev.c:3561
 dev_hard_start_xmit net/core/dev.c:3577 [inline]
 __dev_queue_xmit+0x3310/0x4490 net/core/dev.c:4136
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:4169
 packet_snd net/packet/af_packet.c:2989 [inline]
 packet_sendmsg+0x86e9/0x99c0 net/packet/af_packet.c:3014
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:671 [inline]
 __sys_sendto+0x9dc/0xc80 net/socket.c:1992
 __do_sys_sendto net/socket.c:2004 [inline]
 __se_sys_sendto+0x107/0x130 net/socket.c:2000
 __x64_sys_sendto+0x6e/0x90 net/socket.c:2000
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45de59
Code: 0d 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 db b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f9ae0eeac78 EFLAGS: 00000246 ORIG_RAX: 000000000000002c
RAX: ffffffffffffffda RBX: 000000000002e800 RCX: 000000000045de59
RDX: 000000000000000f RSI: 0000000020000200 RDI: 0000000000000003
RBP: 000000000118bf78 R08: 0000000020000300 R09: 0000000000000080
R10: 0000000020008880 R11: 0000000000000246 R12: 000000000118bf2c
R13: 000000000169fb7f R14: 00007f9ae0eeb9c0 R15: 000000000118bf2c

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:129 [inline]
 kmsan_internal_poison_shadow+0x5c/0xf0 mm/kmsan/kmsan.c:112
 kmsan_slab_alloc+0x8d/0xe0 mm/kmsan/kmsan_hooks.c:80
 slab_alloc_node mm/slub.c:2903 [inline]
 __kmalloc_node_track_caller+0x7de/0x1320 mm/slub.c:4507
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0x309/0xae0 net/core/skbuff.c:210
 alloc_skb include/linux/skbuff.h:1094 [inline]
 alloc_skb_with_frags+0x1f3/0xc20 net/core/skbuff.c:5771
 sock_alloc_send_pskb+0xc73/0xe40 net/core/sock.c:2348
 packet_alloc_skb net/packet/af_packet.c:2837 [inline]
 packet_snd net/packet/af_packet.c:2932 [inline]
 packet_sendmsg+0x6a93/0x99c0 net/packet/af_packet.c:3014
 sock_sendmsg_nosec net/socket.c:651 [inline]
 sock_sendmsg net/socket.c:671 [inline]
 __sys_sendto+0x9dc/0xc80 net/socket.c:1992
 __do_sys_sendto net/socket.c:2004 [inline]
 __se_sys_sendto+0x107/0x130 net/socket.c:2000
 __x64_sys_sendto+0x6e/0x90 net/socket.c:2000
 do_syscall_64+0x9f/0x140 arch/x86/entry/common.c:48
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
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