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BUG: KMSAN: uninit-value in ipt_mangle_out net/ipv4/netfilter/iptable_mangle.c:64 [inline]
BUG: KMSAN: uninit-value in iptable_mangle_hook+0x620/0x720 net/ipv4/netfilter/iptable_mangle.c:84
CPU: 1 PID: 7893 Comm: syz-executor4 Not tainted 4.19.0-rc4+ #63
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+0x306/0x460 lib/dump_stack.c:113
 kmsan_report+0x1a3/0x2d0 mm/kmsan/kmsan.c:917
 __msan_warning+0x7c/0xe0 mm/kmsan/kmsan_instr.c:500
 ipt_mangle_out net/ipv4/netfilter/iptable_mangle.c:64 [inline]
 iptable_mangle_hook+0x620/0x720 net/ipv4/netfilter/iptable_mangle.c:84
 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:242 [inline]
 __ip_local_out+0x6f2/0x810 net/ipv4/ip_output.c:113
 ip_local_out+0xa4/0x1d0 net/ipv4/ip_output.c:122
 iptunnel_xmit+0x835/0xd50 net/ipv4/ip_tunnel_core.c:91
 ip_tunnel_xmit+0x3647/0x3b40 net/ipv4/ip_tunnel.c:778
 __gre_xmit net/ipv4/ip_gre.c:454 [inline]
 ipgre_xmit+0xf59/0x1070 net/ipv4/ip_gre.c:708
 __netdev_start_xmit include/linux/netdevice.h:4287 [inline]
 netdev_start_xmit include/linux/netdevice.h:4296 [inline]
 xmit_one net/core/dev.c:3216 [inline]
 dev_hard_start_xmit+0x6b8/0xdb0 net/core/dev.c:3232
 __dev_queue_xmit+0x2e62/0x3d90 net/core/dev.c:3802
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3835
 packet_snd net/packet/af_packet.c:2925 [inline]
 packet_sendmsg+0x840f/0x8fe0 net/packet/af_packet.c:2950
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 ___sys_sendmsg+0xe47/0x1200 net/socket.c:2114
 __sys_sendmsg net/socket.c:2152 [inline]
 __do_sys_sendmsg net/socket.c:2161 [inline]
 __se_sys_sendmsg+0x307/0x460 net/socket.c:2159
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2159
 do_syscall_64+0xbe/0x100 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x457579
Code: 1d 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 eb b3 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f0cd9964c78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000457579
RDX: 0000000000000000 RSI: 0000000020000200 RDI: 0000000000000003
RBP: 000000000072bf00 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f0cd99656d4
R13: 00000000004c3837 R14: 00000000004d5640 R15: 00000000ffffffff

Uninit was stored to memory at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:255 [inline]
 kmsan_save_stack mm/kmsan/kmsan.c:270 [inline]
 kmsan_internal_chain_origin+0x136/0x240 mm/kmsan/kmsan.c:572
 __msan_chain_origin+0x75/0xd0 mm/kmsan/kmsan_instr.c:337
 iptunnel_xmit+0xa39/0xd50 net/ipv4/ip_tunnel_core.c:85
 ip_tunnel_xmit+0x3647/0x3b40 net/ipv4/ip_tunnel.c:778
 __gre_xmit net/ipv4/ip_gre.c:454 [inline]
 ipgre_xmit+0xf59/0x1070 net/ipv4/ip_gre.c:708
 __netdev_start_xmit include/linux/netdevice.h:4287 [inline]
 netdev_start_xmit include/linux/netdevice.h:4296 [inline]
 xmit_one net/core/dev.c:3216 [inline]
 dev_hard_start_xmit+0x6b8/0xdb0 net/core/dev.c:3232
 __dev_queue_xmit+0x2e62/0x3d90 net/core/dev.c:3802
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3835
 packet_snd net/packet/af_packet.c:2925 [inline]
 packet_sendmsg+0x840f/0x8fe0 net/packet/af_packet.c:2950
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 ___sys_sendmsg+0xe47/0x1200 net/socket.c:2114
 __sys_sendmsg net/socket.c:2152 [inline]
 __do_sys_sendmsg net/socket.c:2161 [inline]
 __se_sys_sendmsg+0x307/0x460 net/socket.c:2159
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2159
 do_syscall_64+0xbe/0x100 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:255 [inline]
 kmsan_internal_poison_shadow+0xc8/0x1d0 mm/kmsan/kmsan.c:180
 kmsan_kmalloc+0xa4/0x120 mm/kmsan/kmsan_hooks.c:93
 kmsan_slab_alloc+0x10/0x20 mm/kmsan/kmsan_hooks.c:102
 slab_post_alloc_hook mm/slab.h:446 [inline]
 slab_alloc_node mm/slub.c:2727 [inline]
 __kmalloc_node_track_caller+0xb43/0x1400 mm/slub.c:4360
 __kmalloc_reserve net/core/skbuff.c:138 [inline]
 __alloc_skb+0x422/0xe90 net/core/skbuff.c:206
 alloc_skb include/linux/skbuff.h:996 [inline]
 alloc_skb_with_frags+0x1d0/0xac0 net/core/skbuff.c:5273
 sock_alloc_send_pskb+0xe00/0x1420 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+0x6787/0x8fe0 net/packet/af_packet.c:2950
 sock_sendmsg_nosec net/socket.c:621 [inline]
 sock_sendmsg net/socket.c:631 [inline]
 ___sys_sendmsg+0xe47/0x1200 net/socket.c:2114
 __sys_sendmsg net/socket.c:2152 [inline]
 __do_sys_sendmsg net/socket.c:2161 [inline]
 __se_sys_sendmsg+0x307/0x460 net/socket.c:2159
 __x64_sys_sendmsg+0x4a/0x70 net/socket.c:2159
 do_syscall_64+0xbe/0x100 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
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