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BUG: KMSAN: uninit-value in bpf_prog_run_generic_xdp+0x14a3/0x1ff0 net/core/dev.c:5291
 bpf_prog_run_generic_xdp+0x14a3/0x1ff0 net/core/dev.c:5291
 netif_receive_generic_xdp net/core/dev.c:5376 [inline]
 do_xdp_generic+0xd52/0x1690 net/core/dev.c:5438
 __netif_receive_skb_core+0x2524/0x6df0 net/core/dev.c:5789
 __netif_receive_skb_one_core net/core/dev.c:5977 [inline]
 __netif_receive_skb+0xcc/0xac0 net/core/dev.c:6092
 process_backlog+0x485/0xa00 net/core/dev.c:6444
 __napi_poll+0xda/0x8a0 net/core/dev.c:7489
 napi_poll net/core/dev.c:7552 [inline]
 net_rx_action+0xa59/0x1ac0 net/core/dev.c:7679
 handle_softirqs+0x166/0x6e0 kernel/softirq.c:579
 __do_softirq+0x14/0x1b kernel/softirq.c:613
 do_softirq+0x99/0x100 kernel/softirq.c:480
 __local_bh_enable_ip+0xa1/0xb0 kernel/softirq.c:407
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 tun_rx_batched+0x889/0x980 drivers/net/tun.c:-1
 tun_get_user+0x5028/0x6ca0 drivers/net/tun.c:1950
 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1996
 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+0x3014/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 __alloc_frozen_pages_noprof+0x689/0xf00 mm/page_alloc.c:5171
 alloc_pages_mpol+0x328/0x860 mm/mempolicy.c:2416
 alloc_frozen_pages_noprof mm/mempolicy.c:2487 [inline]
 alloc_pages_noprof+0x102/0x280 mm/mempolicy.c:2507
 skb_page_frag_refill+0x34e/0x740 net/core/sock.c:3131
 tun_build_skb drivers/net/tun.c:1620 [inline]
 tun_get_user+0x1d71/0x6ca0 drivers/net/tun.c:1770
 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1996
 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+0x3014/0x3e20 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x210 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 8705 Comm: syz.3.760 Not tainted 6.16.0-syzkaller-12250-gc30a13538d9f #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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