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BUG: KMSAN: uninit-value in bpf_prog_run_generic_xdp+0x14a3/0x1ff0 net/core/dev.c:5204
 bpf_prog_run_generic_xdp+0x14a3/0x1ff0 net/core/dev.c:5204
 netif_receive_generic_xdp net/core/dev.c:5286 [inline]
 do_xdp_generic+0xd42/0x1680 net/core/dev.c:5348
 __netif_receive_skb_core+0x2533/0x70c0 net/core/dev.c:5698
 __netif_receive_skb_one_core net/core/dev.c:5885 [inline]
 __netif_receive_skb+0xcc/0xac0 net/core/dev.c:6000
 process_backlog+0x485/0xa00 net/core/dev.c:6352
 __napi_poll+0xda/0x9c0 net/core/dev.c:7324
 napi_poll net/core/dev.c:7388 [inline]
 net_rx_action+0xa0a/0x18f0 net/core/dev.c:7510
 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+0x52a7/0x6a80 drivers/net/tun.c:1938
 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1984
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0xb31/0x1560 fs/read_write.c:684
 ksys_write fs/read_write.c:736 [inline]
 __do_sys_write fs/read_write.c:747 [inline]
 __se_sys_write fs/read_write.c:744 [inline]
 __x64_sys_write+0x1fb/0x4d0 fs/read_write.c:744
 x64_sys_call+0x38c3/0x3db0 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0x1b0 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:4167 [inline]
 slab_alloc_node mm/slub.c:4210 [inline]
 __do_kmalloc_node mm/slub.c:4340 [inline]
 __kmalloc_node_track_caller_noprof+0x96d/0x12f0 mm/slub.c:4360
 kmalloc_reserve+0x22f/0x4b0 net/core/skbuff.c:599
 pskb_expand_head+0x207/0x1c90 net/core/skbuff.c:2247
 netif_skb_check_for_xdp net/core/dev.c:5249 [inline]
 netif_receive_generic_xdp net/core/dev.c:5280 [inline]
 do_xdp_generic+0xa69/0x1680 net/core/dev.c:5348
 __netif_receive_skb_core+0x2533/0x70c0 net/core/dev.c:5698
 __netif_receive_skb_one_core net/core/dev.c:5885 [inline]
 __netif_receive_skb+0xcc/0xac0 net/core/dev.c:6000
 process_backlog+0x485/0xa00 net/core/dev.c:6352
 __napi_poll+0xda/0x9c0 net/core/dev.c:7324
 napi_poll net/core/dev.c:7388 [inline]
 net_rx_action+0xa0a/0x18f0 net/core/dev.c:7510
 handle_softirqs+0x166/0x6e0 kernel/softirq.c:579
 __do_softirq+0x14/0x1b kernel/softirq.c:613

CPU: 1 UID: 0 PID: 29629 Comm: syz.4.3273 Not tainted 6.15.0-rc3-syzkaller-00094-g02ddfb981de8 #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025
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