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BUG: KMSAN: uninit-value in eth_skb_pkt_type include/linux/etherdevice.h:627 [inline]
BUG: KMSAN: uninit-value in eth_type_trans+0x477/0x9b0 net/ethernet/eth.c:165
 eth_skb_pkt_type include/linux/etherdevice.h:627 [inline]
 eth_type_trans+0x477/0x9b0 net/ethernet/eth.c:165
 bpf_prog_run_generic_xdp+0x1201/0x1f40 net/core/dev.c:5468
 netif_receive_generic_xdp net/core/dev.c:5547 [inline]
 do_xdp_generic+0xd51/0x1690 net/core/dev.c:5609
 tun_get_user+0x5061/0x6c80 drivers/net/tun.c:1872
 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0xbe1/0x15c0 fs/read_write.c:686
 ksys_write+0x1d9/0x470 fs/read_write.c:738
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x97/0xf0 fs/read_write.c:746
 x64_sys_call+0x30ab/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

Uninit was stored to memory at:
 pskb_expand_head+0x307/0x15a0 net/core/skbuff.c:2290
 netif_skb_check_for_xdp net/core/dev.c:5510 [inline]
 netif_receive_generic_xdp net/core/dev.c:5541 [inline]
 do_xdp_generic+0xa78/0x1690 net/core/dev.c:5609
 tun_get_user+0x5061/0x6c80 drivers/net/tun.c:1872
 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0xbe1/0x15c0 fs/read_write.c:686
 ksys_write+0x1d9/0x470 fs/read_write.c:738
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x97/0xf0 fs/read_write.c:746
 x64_sys_call+0x30ab/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0xf80 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:4960 [inline]
 slab_alloc_node mm/slub.c:5263 [inline]
 __do_kmalloc_node mm/slub.c:5656 [inline]
 __kmalloc_node_track_caller_noprof+0xb6e/0x1c70 mm/slub.c:5768
 kmalloc_reserve+0x22f/0x4b0 net/core/skbuff.c:608
 __alloc_skb+0x805/0x1030 net/core/skbuff.c:690
 alloc_skb include/linux/skbuff.h:1383 [inline]
 alloc_skb_with_frags+0xc5/0xa60 net/core/skbuff.c:6714
 sock_alloc_send_pskb+0xacb/0xc60 net/core/sock.c:2995
 tun_alloc_skb drivers/net/tun.c:1461 [inline]
 tun_get_user+0xd29/0x6c80 drivers/net/tun.c:1794
 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0xbe1/0x15c0 fs/read_write.c:686
 ksys_write+0x1d9/0x470 fs/read_write.c:738
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x97/0xf0 fs/read_write.c:746
 x64_sys_call+0x30ab/0x3e70 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xc9/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 1 UID: 0 PID: 8931 Comm: syz.4.647 Tainted: G             L      syzkaller #0 PREEMPT(voluntary) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/13/2026
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