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BUG: KMSAN: uninit-value in __arch_swab32 arch/x86/include/uapi/asm/swab.h:10 [inline]
BUG: KMSAN: uninit-value in __fswab32 include/uapi/linux/swab.h:60 [inline]
BUG: KMSAN: uninit-value in gre_parse_header+0x1627/0x1950 net/ipv4/gre_demux.c:139
CPU: 0 PID: 9539 Comm: syz-executor.0 Not tainted 5.8.0-rc5-syzkaller #0
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+0x1df/0x240 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215
 __arch_swab32 arch/x86/include/uapi/asm/swab.h:10 [inline]
 __fswab32 include/uapi/linux/swab.h:60 [inline]
 gre_parse_header+0x1627/0x1950 net/ipv4/gre_demux.c:139
 gre_rcv+0x1cf/0x1c10 net/ipv4/ip_gre.c:431
 gre_rcv+0x2dd/0x3c0 net/ipv4/gre_demux.c:163
 ip_protocol_deliver_rcu+0x700/0xbc0 net/ipv4/ip_input.c:204
 ip_local_deliver_finish net/ipv4/ip_input.c:231 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 ip_local_deliver+0x62a/0x7c0 net/ipv4/ip_input.c:252
 dst_input include/net/dst.h:449 [inline]
 ip_rcv_finish net/ipv4/ip_input.c:428 [inline]
 NF_HOOK include/linux/netfilter.h:307 [inline]
 ip_rcv+0x6cf/0x750 net/ipv4/ip_input.c:539
 __netif_receive_skb_one_core net/core/dev.c:5281 [inline]
 __netif_receive_skb net/core/dev.c:5395 [inline]
 process_backlog+0xfb5/0x14e0 net/core/dev.c:6239
 napi_poll net/core/dev.c:6684 [inline]
 net_rx_action+0x746/0x1aa0 net/core/dev.c:6752
 __do_softirq+0x311/0x83d kernel/softirq.c:293
 asm_call_on_stack+0x12/0x20 arch/x86/entry/entry_64.S:711
 </IRQ>
 __run_on_irqstack arch/x86/include/asm/irq_stack.h:23 [inline]
 run_on_irqstack_cond arch/x86/include/asm/irq_stack.h:50 [inline]
 do_softirq_own_stack+0x7c/0xa0 arch/x86/kernel/irq_64.c:77
 do_softirq kernel/softirq.c:338 [inline]
 __local_bh_enable_ip+0x184/0x1d0 kernel/softirq.c:190
 local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
 rcu_read_unlock_bh include/linux/rcupdate.h:723 [inline]
 ip_finish_output2+0x1fee/0x24a0 net/ipv4/ip_output.c:229
 __ip_finish_output+0xaa7/0xd80 net/ipv4/ip_output.c:306
 ip_finish_output+0x166/0x410 net/ipv4/ip_output.c:316
 NF_HOOK_COND include/linux/netfilter.h:296 [inline]
 ip_output+0x593/0x680 net/ipv4/ip_output.c:430
 dst_output include/net/dst.h:443 [inline]
 ip_local_out net/ipv4/ip_output.c:125 [inline]
 __ip_queue_xmit+0x1b5c/0x21a0 net/ipv4/ip_output.c:530
 ip_queue_xmit+0xcc/0xf0 include/net/ip.h:237
 __tcp_transmit_skb+0x440e/0x6090 net/ipv4/tcp_output.c:1240
 tcp_transmit_skb net/ipv4/tcp_output.c:1256 [inline]
 tcp_connect+0x4208/0x6830 net/ipv4/tcp_output.c:3673
 tcp_v6_connect+0x259c/0x2780 net/ipv6/tcp_ipv6.c:334
 __inet_stream_connect+0x2fb/0x1340 net/ipv4/af_inet.c:658
 inet_stream_connect+0x101/0x180 net/ipv4/af_inet.c:722
 __sys_connect_file net/socket.c:1854 [inline]
 __sys_connect+0x6f7/0x770 net/socket.c:1871
 __do_sys_connect net/socket.c:1882 [inline]
 __se_sys_connect+0x8d/0xb0 net/socket.c:1879
 __x64_sys_connect+0x4a/0x70 net/socket.c:1879
 do_syscall_64+0xb0/0x150 arch/x86/entry/common.c:386
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45a999
Code: Bad RIP value.
RSP: 002b:00007f6817bafc78 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 000000000045a999
RDX: 000000000000001c RSI: 0000000020000140 RDI: 0000000000000004
RBP: 000000000075bfc8 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007f6817bb06d4
R13: 00000000004c112b R14: 00000000004d4f18 R15: 00000000ffffffff

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline]
 kmsan_internal_poison_shadow+0x66/0xd0 mm/kmsan/kmsan.c:127
 kmsan_slab_alloc+0x8a/0xe0 mm/kmsan/kmsan_hooks.c:80
 slab_alloc_node mm/slub.c:2839 [inline]
 __kmalloc_node_track_caller+0xb40/0x1200 mm/slub.c:4478
 __kmalloc_reserve net/core/skbuff.c:142 [inline]
 __alloc_skb+0x2fd/0xac0 net/core/skbuff.c:210
 alloc_skb_fclone include/linux/skbuff.h:1133 [inline]
 sk_stream_alloc_skb+0x3ee/0x1180 net/ipv4/tcp.c:884
 tcp_connect+0x2a78/0x6830 net/ipv4/tcp_output.c:3660
 tcp_v6_connect+0x259c/0x2780 net/ipv6/tcp_ipv6.c:334
 __inet_stream_connect+0x2fb/0x1340 net/ipv4/af_inet.c:658
 inet_stream_connect+0x101/0x180 net/ipv4/af_inet.c:722
 __sys_connect_file net/socket.c:1854 [inline]
 __sys_connect+0x6f7/0x770 net/socket.c:1871
 __do_sys_connect net/socket.c:1882 [inline]
 __se_sys_connect+0x8d/0xb0 net/socket.c:1879
 __x64_sys_connect+0x4a/0x70 net/socket.c:1879
 do_syscall_64+0xb0/0x150 arch/x86/entry/common.c:386
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
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