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BUG: KMSAN: uninit-value in eth_skb_pkt_type include/linux/etherdevice.h:628 [inline]
BUG: KMSAN: uninit-value in eth_type_trans+0x7d5/0x9b0 net/ethernet/eth.c:165
 eth_skb_pkt_type include/linux/etherdevice.h:628 [inline]
 eth_type_trans+0x7d5/0x9b0 net/ethernet/eth.c:165
 bpf_prog_run_generic_xdp+0x1313/0x20d0 net/core/dev.c:5465
 netif_receive_generic_xdp net/core/dev.c:5544 [inline]
 do_xdp_generic+0xdef/0x1760 net/core/dev.c:5606
 tun_get_user+0x525a/0x7830 drivers/net/tun.c:1872
 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_int80_emulation+0x15a/0x330 arch/x86/entry/syscall_32.c:172
 asm_int80_emulation+0x1f/0x30 arch/x86/include/asm/idtentry.h:621

Uninit was stored to memory at:
 pskb_expand_head+0x4a0/0x1fb0 net/core/skbuff.c:2323
 netif_skb_check_for_xdp net/core/dev.c:5507 [inline]
 netif_receive_generic_xdp net/core/dev.c:5538 [inline]
 do_xdp_generic+0xb18/0x1760 net/core/dev.c:5606
 tun_get_user+0x525a/0x7830 drivers/net/tun.c:1872
 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_int80_emulation+0x15a/0x330 arch/x86/entry/syscall_32.c:172
 asm_int80_emulation+0x1f/0x30 arch/x86/include/asm/idtentry.h:621

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4466 [inline]
 slab_alloc_node mm/slub.c:4788 [inline]
 __do_kmalloc_node mm/slub.c:5176 [inline]
 __kmalloc_node_track_caller_noprof+0x4ff/0x1710 mm/slub.c:5285
 kmalloc_reserve net/core/skbuff.c:635 [inline]
 __alloc_skb+0x90d/0x1190 net/core/skbuff.c:713
 alloc_skb include/linux/skbuff.h:1383 [inline]
 alloc_skb_with_frags+0xc5/0xa60 net/core/skbuff.c:6750
 sock_alloc_send_pskb+0xacb/0xc60 net/core/sock.c:2995
 tun_alloc_skb drivers/net/tun.c:1461 [inline]
 tun_get_user+0xcfc/0x7830 drivers/net/tun.c:1794
 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_int80_emulation+0x15a/0x330 arch/x86/entry/syscall_32.c:172
 asm_int80_emulation+0x1f/0x30 arch/x86/include/asm/idtentry.h:621

CPU: 0 UID: 0 PID: 13950 Comm: syz.0.2876 Not tainted syzkaller #0 PREEMPT(full) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/24/2026
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