=====================================================
BUG: KMSAN: uninit-value in bpf_prog_run_generic_xdp+0x143f/0x1fc0 net/core/dev.c:5447
 bpf_prog_run_generic_xdp+0x143f/0x1fc0 net/core/dev.c:5447
 netif_receive_generic_xdp net/core/dev.c:5532 [inline]
 do_xdp_generic+0xd52/0x1690 net/core/dev.c:5594
 __netif_receive_skb_core+0x1b1d/0x4d10 net/core/dev.c:5947
 __netif_receive_skb_one_core net/core/dev.c:6135 [inline]
 __netif_receive_skb+0xcc/0xac0 net/core/dev.c:6250
 process_backlog+0x47c/0x9f0 net/core/dev.c:6602
 __napi_poll+0xd8/0x880 net/core/dev.c:7666
 napi_poll net/core/dev.c:7729 [inline]
 net_rx_action+0xa3f/0x1c90 net/core/dev.c:7881
 handle_softirqs+0x169/0x6e0 kernel/softirq.c:622
 __do_softirq+0x14/0x1b kernel/softirq.c:656
 do_softirq+0x99/0x100 kernel/softirq.c:523
 __local_bh_enable_ip+0xa1/0xb0 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 tun_rx_batched+0x889/0x980 drivers/net/tun.c:-1
 tun_get_user+0x5c0e/0x6c60 drivers/net/tun.c:1953
 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0xbe2/0x15d0 fs/read_write.c:686
 ksys_write fs/read_write.c:738 [inline]
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746
 x64_sys_call+0x30ab/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 __alloc_frozen_pages_noprof+0x421/0xab0 mm/page_alloc.c:5233
 alloc_pages_mpol+0x328/0x860 mm/mempolicy.c:2486
 alloc_frozen_pages_noprof mm/mempolicy.c:2557 [inline]
 alloc_pages_noprof+0x102/0x280 mm/mempolicy.c:2577
 skb_page_frag_refill+0x34e/0x740 net/core/sock.c:3146
 tun_build_skb drivers/net/tun.c:1620 [inline]
 tun_get_user+0x1d7f/0x6c60 drivers/net/tun.c:1770
 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0xbe2/0x15d0 fs/read_write.c:686
 ksys_write fs/read_write.c:738 [inline]
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:746
 x64_sys_call+0x30ab/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 14198 Comm: syz.3.2431 Tainted: G        W    L      syzkaller #0 PREEMPT(none) 
Tainted: [W]=WARN, [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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