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BUG: KMSAN: uninit-value in bpf_prog_run_generic_xdp+0x1465/0x2000 net/core/dev.c:5391
 bpf_prog_run_generic_xdp+0x1465/0x2000 net/core/dev.c:5391
 netif_receive_generic_xdp net/core/dev.c:5476 [inline]
 do_xdp_generic+0xd52/0x1690 net/core/dev.c:5538
 __netif_receive_skb_core+0x2bc2/0x7150 net/core/dev.c:5889
 __netif_receive_skb_one_core net/core/dev.c:6077 [inline]
 __netif_receive_skb+0xcc/0xac0 net/core/dev.c:6192
 process_backlog+0x485/0xa00 net/core/dev.c:6544
 __napi_poll+0xdd/0x8a0 net/core/dev.c:7594
 napi_poll net/core/dev.c:7657 [inline]
 net_rx_action+0xbc8/0x1c30 net/core/dev.c:7784
 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+0x5d62/0x6d70 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+0x3014/0x3e30 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xd9/0xfa0 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:4985 [inline]
 slab_alloc_node mm/slub.c:5288 [inline]
 __do_kmalloc_node mm/slub.c:5649 [inline]
 __kmalloc_node_track_caller_noprof+0xb4b/0x1ba0 mm/slub.c:5759
 kmalloc_reserve+0x22f/0x4b0 net/core/skbuff.c:601
 pskb_expand_head+0x1fc/0x1610 net/core/skbuff.c:2241
 netif_skb_check_for_xdp net/core/dev.c:5439 [inline]
 netif_receive_generic_xdp net/core/dev.c:5470 [inline]
 do_xdp_generic+0xa79/0x1690 net/core/dev.c:5538
 __netif_receive_skb_core+0x2bc2/0x7150 net/core/dev.c:5889
 __netif_receive_skb_one_core net/core/dev.c:6077 [inline]
 __netif_receive_skb+0xcc/0xac0 net/core/dev.c:6192
 process_backlog+0x485/0xa00 net/core/dev.c:6544
 __napi_poll+0xdd/0x8a0 net/core/dev.c:7594
 napi_poll net/core/dev.c:7657 [inline]
 net_rx_action+0xbc8/0x1c30 net/core/dev.c:7784
 handle_softirqs+0x169/0x6e0 kernel/softirq.c:622
 __do_softirq+0x14/0x1b kernel/softirq.c:656

CPU: 1 UID: 0 PID: 10408 Comm: syz.1.1259 Not tainted syzkaller #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
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