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BUG: KMSAN: uninit-value in bpf_prog_run_generic_xdp+0x11c2/0x20d0 net/core/dev.c:5491
 bpf_prog_run_generic_xdp+0x11c2/0x20d0 net/core/dev.c:5491
 netif_receive_generic_xdp net/core/dev.c:5576 [inline]
 do_xdp_generic+0xe07/0x17f0 net/core/dev.c:5638
 __netif_receive_skb_core+0x1a46/0x4dc0 net/core/dev.c:5991
 __netif_receive_skb_one_core net/core/dev.c:6179 [inline]
 __netif_receive_skb net/core/dev.c:6294 [inline]
 process_backlog+0x514/0x1500 net/core/dev.c:6645
 __napi_poll+0xdc/0x950 net/core/dev.c:7709
 napi_poll net/core/dev.c:7772 [inline]
 net_rx_action+0xa5b/0x1c70 net/core/dev.c:7929
 handle_softirqs+0x171/0x7e0 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+0x6002/0x7830 drivers/net/tun.c:1953
 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999
 new_sync_write fs/read_write.c:595 [inline]
 vfs_write+0xbe1/0x15c0 fs/read_write.c:688
 ksys_write+0x1d9/0x470 fs/read_write.c:740
 __do_sys_write fs/read_write.c:751 [inline]
 __se_sys_write fs/read_write.c:748 [inline]
 __ia32_sys_write+0x9a/0xf0 fs/read_write.c:748
 ia32_sys_call+0x37a7/0x4360 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+0x17f/0x420 arch/x86/entry/syscall_32.c:307
 do_fast_syscall_32+0x37/0x80 arch/x86/entry/syscall_32.c:332
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/syscall_32.c:370
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4545 [inline]
 slab_alloc_node mm/slub.c:4866 [inline]
 __do_kmalloc_node mm/slub.c:5259 [inline]
 __kmalloc_node_track_caller_noprof+0x4f6/0x1750 mm/slub.c:5368
 kmalloc_reserve net/core/skbuff.c:635 [inline]
 pskb_expand_head+0x3d1/0x1e00 net/core/skbuff.c:2312
 netif_skb_check_for_xdp net/core/dev.c:5539 [inline]
 netif_receive_generic_xdp net/core/dev.c:5570 [inline]
 do_xdp_generic+0xb30/0x17f0 net/core/dev.c:5638
 __netif_receive_skb_core+0x1a46/0x4dc0 net/core/dev.c:5991
 __netif_receive_skb_one_core net/core/dev.c:6179 [inline]
 __netif_receive_skb net/core/dev.c:6294 [inline]
 process_backlog+0x514/0x1500 net/core/dev.c:6645
 __napi_poll+0xdc/0x950 net/core/dev.c:7709
 napi_poll net/core/dev.c:7772 [inline]
 net_rx_action+0xa5b/0x1c70 net/core/dev.c:7929
 handle_softirqs+0x171/0x7e0 kernel/softirq.c:622
 __do_softirq+0x14/0x1b kernel/softirq.c:656

CPU: 0 UID: 0 PID: 21631 Comm: syz.2.4983 Tainted: G             L      syzkaller #0 PREEMPT(full) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 03/18/2026
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