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BUG: KMSAN: uninit-value in bpf_prog_run_generic_xdp+0x1a97/0x20d0 net/core/dev.c:5461
 bpf_prog_run_generic_xdp+0x1a97/0x20d0 net/core/dev.c:5461
 netif_receive_generic_xdp net/core/dev.c:5544 [inline]
 do_xdp_generic+0xe07/0x17f0 net/core/dev.c:5606
 __netif_receive_skb_core+0x1a46/0x4dc0 net/core/dev.c:5959
 __netif_receive_skb_one_core net/core/dev.c:6147 [inline]
 __netif_receive_skb net/core/dev.c:6262 [inline]
 netif_receive_skb_internal net/core/dev.c:6348 [inline]
 netif_receive_skb+0xf2/0x1160 net/core/dev.c:6407
 tun_rx_batched+0x1da/0x980 drivers/net/tun.c:1485
 tun_get_user+0x6002/0x7830 drivers/net/tun.c:1953
 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0xbe1/0x15c0 fs/read_write.c:688
 ksys_write+0x1d9/0x470 fs/read_write.c:740
 __do_sys_write fs/read_write.c:751 [inline]
 __se_sys_write fs/read_write.c:748 [inline]
 __x64_sys_write+0x97/0xf0 fs/read_write.c:748
 x64_sys_call+0x2ff0/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 pskb_expand_head+0x4a0/0x1fb0 net/core/skbuff.c:2323
 netif_skb_check_for_xdp net/core/dev.c:5507 [inline]
 netif_receive_generic_xdp net/core/dev.c:5538 [inline]
 do_xdp_generic+0xb30/0x17f0 net/core/dev.c:5606
 __netif_receive_skb_core+0x1a46/0x4dc0 net/core/dev.c:5959
 __netif_receive_skb_one_core net/core/dev.c:6147 [inline]
 __netif_receive_skb net/core/dev.c:6262 [inline]
 netif_receive_skb_internal net/core/dev.c:6348 [inline]
 netif_receive_skb+0xf2/0x1160 net/core/dev.c:6407
 tun_rx_batched+0x1da/0x980 drivers/net/tun.c:1485
 tun_get_user+0x6002/0x7830 drivers/net/tun.c:1953
 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0xbe1/0x15c0 fs/read_write.c:688
 ksys_write+0x1d9/0x470 fs/read_write.c:740
 __do_sys_write fs/read_write.c:751 [inline]
 __se_sys_write fs/read_write.c:748 [inline]
 __x64_sys_write+0x97/0xf0 fs/read_write.c:748
 x64_sys_call+0x2ff0/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 __alloc_frozen_pages_noprof+0x6f7/0x1020 mm/page_alloc.c:5272
 alloc_pages_mpol+0x328/0x860 mm/mempolicy.c:2485
 alloc_frozen_pages_noprof mm/mempolicy.c:2556 [inline]
 alloc_pages_noprof+0x101/0x280 mm/mempolicy.c:2576
 skb_page_frag_refill+0x34e/0x730 net/core/sock.c:3146
 tun_build_skb drivers/net/tun.c:1620 [inline]
 tun_get_user+0x1d9a/0x7830 drivers/net/tun.c:1770
 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0xbe1/0x15c0 fs/read_write.c:688
 ksys_write+0x1d9/0x470 fs/read_write.c:740
 __do_sys_write fs/read_write.c:751 [inline]
 __se_sys_write fs/read_write.c:748 [inline]
 __x64_sys_write+0x97/0xf0 fs/read_write.c:748
 x64_sys_call+0x2ff0/0x3ea0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0x134/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 12310 Comm: syz.0.1156 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2026
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