=====================================================
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+0xa45/0x1c90 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:
 slab_post_alloc_hook mm/slub.c:4955 [inline]
 slab_alloc_node mm/slub.c:5258 [inline]
 __do_kmalloc_node mm/slub.c:5651 [inline]
 __kmalloc_node_track_caller_noprof+0xb77/0x1c90 mm/slub.c:5759
 kmalloc_reserve+0x22f/0x4b0 net/core/skbuff.c:608
 pskb_expand_head+0x1fc/0x15d0 net/core/skbuff.c:2282
 netif_skb_check_for_xdp net/core/dev.c:5495 [inline]
 netif_receive_generic_xdp net/core/dev.c:5526 [inline]
 do_xdp_generic+0xa79/0x1690 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+0xa45/0x1c90 net/core/dev.c:7881
 handle_softirqs+0x169/0x6e0 kernel/softirq.c:622
 __do_softirq+0x14/0x1b kernel/softirq.c:656

CPU: 0 UID: 0 PID: 30874 Comm: syz.9.7140 Tainted: G             L      syzkaller #0 PREEMPT(none) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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