=====================================================
BUG: KMSAN: uninit-value in tcp_sack net/netfilter/nf_conntrack_proto_tcp.c:425 [inline]
BUG: KMSAN: uninit-value in tcp_in_window net/netfilter/nf_conntrack_proto_tcp.c:489 [inline]
BUG: KMSAN: uninit-value in nf_conntrack_tcp_packet+0x3266/0x7650 net/netfilter/nf_conntrack_proto_tcp.c:1091
CPU: 1 PID: 13233 Comm: syz-executor.1 Not tainted 5.4.0-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+0x1c9/0x220 lib/dump_stack.c:118
 kmsan_report+0x128/0x220 mm/kmsan/kmsan_report.c:108
 __msan_warning+0x57/0xa0 mm/kmsan/kmsan_instr.c:245
 tcp_sack net/netfilter/nf_conntrack_proto_tcp.c:425 [inline]
 tcp_in_window net/netfilter/nf_conntrack_proto_tcp.c:489 [inline]
 nf_conntrack_tcp_packet+0x3266/0x7650 net/netfilter/nf_conntrack_proto_tcp.c:1091
 nf_conntrack_handle_packet net/netfilter/nf_conntrack_core.c:1632 [inline]
 nf_conntrack_in+0x1064/0x2664 net/netfilter/nf_conntrack_core.c:1726
 ipv4_conntrack_local+0x1b7/0x300 net/netfilter/nf_conntrack_proto.c:200
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0x18b/0x3f0 net/netfilter/core.c:512
 nf_hook include/linux/netfilter.h:260 [inline]
 __ip_local_out+0x69b/0x800 net/ipv4/ip_output.c:114
 ip_local_out net/ipv4/ip_output.c:123 [inline]
 __ip_queue_xmit+0x1bdc/0x21f0 net/ipv4/ip_output.c:532
 ip_queue_xmit+0xcc/0xf0 include/net/ip.h:237
 __tcp_transmit_skb+0x40e3/0x5d90 net/ipv4/tcp_output.c:1169
 __tcp_send_ack+0x701/0x840 net/ipv4/tcp_output.c:3696
 tcp_send_ack+0x68/0x90 net/ipv4/tcp_output.c:3702
 __tcp_ack_snd_check+0x643/0xb40 net/ipv4/tcp_input.c:5243
 tcp_ack_snd_check net/ipv4/tcp_input.c:5289 [inline]
 tcp_rcv_state_process+0x53f7/0x6f80 net/ipv4/tcp_input.c:6355
 tcp_v4_do_rcv+0xb11/0xd70 net/ipv4/tcp_ipv4.c:1586
 sk_backlog_rcv include/net/sock.h:950 [inline]
 __release_sock+0x448/0x640 net/core/sock.c:2439
 release_sock+0x99/0x2a0 net/core/sock.c:2955
 inet_shutdown+0x580/0x5f0 net/ipv4/af_inet.c:898
 __sys_shutdown net/socket.c:2160 [inline]
 __do_sys_shutdown net/socket.c:2168 [inline]
 __se_sys_shutdown+0x28b/0x3e0 net/socket.c:2166
 __x64_sys_shutdown+0x3e/0x60 net/socket.c:2166
 do_syscall_64+0xb6/0x160 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45a679
Code: ad b6 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 b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f74f73a1c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000030
RAX: ffffffffffffffda RBX: 0000000000000002 RCX: 000000000045a679
RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000004
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f74f73a26d4
R13: 00000000004ca442 R14: 00000000004e34b0 R15: 00000000ffffffff

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:149 [inline]
 kmsan_internal_poison_shadow+0x5c/0x110 mm/kmsan/kmsan.c:132
 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:86
 slab_alloc_node mm/slub.c:2773 [inline]
 __kmalloc_node_track_caller+0xe27/0x11a0 mm/slub.c:4381
 __kmalloc_reserve net/core/skbuff.c:141 [inline]
 __alloc_skb+0x306/0xa10 net/core/skbuff.c:209
 alloc_skb include/linux/skbuff.h:1049 [inline]
 __tcp_send_ack+0xfb/0x840 net/ipv4/tcp_output.c:3675
 tcp_send_ack+0x68/0x90 net/ipv4/tcp_output.c:3702
 __tcp_ack_snd_check+0x643/0xb40 net/ipv4/tcp_input.c:5243
 tcp_ack_snd_check net/ipv4/tcp_input.c:5289 [inline]
 tcp_rcv_state_process+0x53f7/0x6f80 net/ipv4/tcp_input.c:6355
 tcp_v4_do_rcv+0xb11/0xd70 net/ipv4/tcp_ipv4.c:1586
 sk_backlog_rcv include/net/sock.h:950 [inline]
 __release_sock+0x448/0x640 net/core/sock.c:2439
 release_sock+0x99/0x2a0 net/core/sock.c:2955
 inet_shutdown+0x580/0x5f0 net/ipv4/af_inet.c:898
 __sys_shutdown net/socket.c:2160 [inline]
 __do_sys_shutdown net/socket.c:2168 [inline]
 __se_sys_shutdown+0x28b/0x3e0 net/socket.c:2166
 __x64_sys_shutdown+0x3e/0x60 net/socket.c:2166
 do_syscall_64+0xb6/0x160 arch/x86/entry/common.c:291
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
=====================================================