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BUG: KMSAN: uninit-value in bpf_prog_run_generic_xdp+0x14d0/0x1f40 net/core/dev.c:5462
 bpf_prog_run_generic_xdp+0x14d0/0x1f40 net/core/dev.c:5462
 netif_receive_generic_xdp net/core/dev.c:5547 [inline]
 do_xdp_generic+0xd51/0x1690 net/core/dev.c:5609
 __netif_receive_skb_core+0x1a84/0x4d80 net/core/dev.c:5962
 __netif_receive_skb_one_core net/core/dev.c:6150 [inline]
 __netif_receive_skb+0xcc/0xac0 net/core/dev.c:6265
 process_backlog+0x479/0x9e0 net/core/dev.c:6617
 __napi_poll+0xdc/0x890 net/core/dev.c:7681
 napi_poll net/core/dev.c:7744 [inline]
 net_rx_action+0xa1c/0x1c20 net/core/dev.c:7896
 handle_softirqs+0x168/0x6e0 kernel/softirq.c:622
 __do_softirq+0x14/0x1b kernel/softirq.c:656
 do_softirq+0x58/0x90 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+0x887/0x980 drivers/net/tun.c:-1
 tun_get_user+0x5c0d/0x6c80 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+0xbe1/0x15c0 fs/read_write.c:686
 ksys_write+0x1d9/0x470 fs/read_write.c:738
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x97/0xf0 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+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4960 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 kmem_cache_alloc_node_noprof+0x9de/0x1780 mm/slub.c:5315
 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:586
 pskb_expand_head+0x1fc/0x15a0 net/core/skbuff.c:2282
 netif_skb_check_for_xdp net/core/dev.c:5510 [inline]
 netif_receive_generic_xdp net/core/dev.c:5541 [inline]
 do_xdp_generic+0xa78/0x1690 net/core/dev.c:5609
 __netif_receive_skb_core+0x1a84/0x4d80 net/core/dev.c:5962
 __netif_receive_skb_one_core net/core/dev.c:6150 [inline]
 __netif_receive_skb+0xcc/0xac0 net/core/dev.c:6265
 process_backlog+0x479/0x9e0 net/core/dev.c:6617
 __napi_poll+0xdc/0x890 net/core/dev.c:7681
 napi_poll net/core/dev.c:7744 [inline]
 net_rx_action+0xa1c/0x1c20 net/core/dev.c:7896
 handle_softirqs+0x168/0x6e0 kernel/softirq.c:622
 __do_softirq+0x14/0x1b kernel/softirq.c:656

CPU: 1 UID: 0 PID: 8732 Comm: syz.1.1083 Not tainted syzkaller #0 PREEMPT(voluntary) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
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