=====================================================
BUG: KMSAN: uninit-value in __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline]
BUG: KMSAN: uninit-value in INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline]
BUG: KMSAN: uninit-value in IP_ECN_decapsulate include/net/inet_ecn.h:302 [inline]
BUG: KMSAN: uninit-value in ip_tunnel_rcv+0xed9/0x2eb0 net/ipv4/ip_tunnel.c:409
 __INET_ECN_decapsulate include/net/inet_ecn.h:253 [inline]
 INET_ECN_decapsulate include/net/inet_ecn.h:275 [inline]
 IP_ECN_decapsulate include/net/inet_ecn.h:302 [inline]
 ip_tunnel_rcv+0xed9/0x2eb0 net/ipv4/ip_tunnel.c:409
 erspan_rcv net/ipv4/ip_gre.c:341 [inline]
 gre_rcv+0x1611/0x19f0 net/ipv4/ip_gre.c:442
 gre_rcv+0x2a4/0x390 net/ipv4/gre_demux.c:163
 ip_protocol_deliver_rcu+0x264/0x1300 net/ipv4/ip_input.c:205
 ip_local_deliver_finish+0x2b8/0x440 net/ipv4/ip_input.c:233
 NF_HOOK include/linux/netfilter.h:314 [inline]
 ip_local_deliver+0x21f/0x490 net/ipv4/ip_input.c:254
 dst_input include/net/dst.h:461 [inline]
 ip_rcv_finish net/ipv4/ip_input.c:449 [inline]
 NF_HOOK include/linux/netfilter.h:314 [inline]
 ip_rcv+0x476/0x770 net/ipv4/ip_input.c:569
 __netif_receive_skb_one_core net/core/dev.c:5532 [inline]
 __netif_receive_skb+0x1a6/0x5a0 net/core/dev.c:5646
 netif_receive_skb_internal net/core/dev.c:5732 [inline]
 netif_receive_skb+0x58/0x660 net/core/dev.c:5791
 tun_rx_batched+0x3ee/0x980 drivers/net/tun.c:1555
 tun_get_user+0x53af/0x66d0 drivers/net/tun.c:2002
 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048
 call_write_iter include/linux/fs.h:2020 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x8ef/0x1490 fs/read_write.c:584
 ksys_write+0x20f/0x4c0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x93/0xd0 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

Uninit was created at:
 __alloc_pages+0x9a4/0xe00 mm/page_alloc.c:4591
 alloc_pages_mpol+0x62b/0x9d0 mm/mempolicy.c:2133
 alloc_pages+0x1be/0x1e0 mm/mempolicy.c:2204
 skb_page_frag_refill+0x2bf/0x7c0 net/core/sock.c:2905
 tun_build_skb drivers/net/tun.c:1679 [inline]
 tun_get_user+0xe0a/0x66d0 drivers/net/tun.c:1819
 tun_chr_write_iter+0x3af/0x5d0 drivers/net/tun.c:2048
 call_write_iter include/linux/fs.h:2020 [inline]
 new_sync_write fs/read_write.c:491 [inline]
 vfs_write+0x8ef/0x1490 fs/read_write.c:584
 ksys_write+0x20f/0x4c0 fs/read_write.c:637
 __do_sys_write fs/read_write.c:649 [inline]
 __se_sys_write fs/read_write.c:646 [inline]
 __x64_sys_write+0x93/0xd0 fs/read_write.c:646
 do_syscall_x64 arch/x86/entry/common.c:52 [inline]
 do_syscall_64+0x44/0x110 arch/x86/entry/common.c:83
 entry_SYSCALL_64_after_hwframe+0x63/0x6b

CPU: 1 PID: 5042 Comm: syz-executor985 Not tainted 6.7.0-rc8-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 11/17/2023
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