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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+0xdd/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+0xb4b/0x1580 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]
 __ia32_sys_write+0x1f9/0x4d0 fs/read_write.c:746
 ia32_sys_call+0x35bc/0x4310 arch/x86/include/generated/asm/syscalls_32.h:5
 do_syscall_32_irqs_on arch/x86/entry/syscall_32.c:83 [inline]
 __do_fast_syscall_32+0xb0/0x150 arch/x86/entry/syscall_32.c:306
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/syscall_32.c:331
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:369
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4186 [inline]
 slab_alloc_node mm/slub.c:4229 [inline]
 __do_kmalloc_node mm/slub.c:4364 [inline]
 __kmalloc_node_track_caller_noprof+0x96d/0x12f0 mm/slub.c:4384
 kmalloc_reserve+0x22f/0x4b0 net/core/skbuff.c:600
 pskb_expand_head+0x1fc/0x1610 net/core/skbuff.c:2240
 netif_skb_check_for_xdp net/core/dev.c:5339 [inline]
 netif_receive_generic_xdp net/core/dev.c:5370 [inline]
 do_xdp_generic+0xa79/0x1690 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+0xdd/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

CPU: 1 UID: 0 PID: 19215 Comm: syz.2.5447 Not tainted 6.16.0-syzkaller-12063-g37816488247d #0 PREEMPT(none) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
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