=====================================================
BUG: KMSAN: uninit-value in bpf_prog_run_generic_xdp+0x190b/0x1f20 net/core/dev.c:5208
 bpf_prog_run_generic_xdp+0x190b/0x1f20 net/core/dev.c:5208
 netif_receive_generic_xdp net/core/dev.c:5290 [inline]
 do_xdp_generic+0xc10/0x15a0 net/core/dev.c:5352
 tun_get_user+0x4b14/0x6b80 drivers/net/tun.c:1860
 tun_chr_write_iter+0x3ac/0x5d0 drivers/net/tun.c:1984
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0xb34/0x1540 fs/read_write.c:684
 ksys_write+0x240/0x4b0 fs/read_write.c:736
 __do_sys_write fs/read_write.c:747 [inline]
 __se_sys_write fs/read_write.c:744 [inline]
 __x64_sys_write+0x93/0xe0 fs/read_write.c:744
 x64_sys_call+0x34de/0x3c80 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x1e0 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:4144 [inline]
 slab_alloc_node mm/slub.c:4187 [inline]
 __do_kmalloc_node mm/slub.c:4317 [inline]
 __kmalloc_node_track_caller_noprof+0x962/0x1260 mm/slub.c:4337
 kmalloc_reserve+0x23e/0x4a0 net/core/skbuff.c:599
 __alloc_skb+0x366/0x7b0 net/core/skbuff.c:668
 alloc_skb include/linux/skbuff.h:1340 [inline]
 alloc_skb_with_frags+0xc8/0xd10 net/core/skbuff.c:6639
 sock_alloc_send_pskb+0xa81/0xbf0 net/core/sock.c:2949
 tun_alloc_skb drivers/net/tun.c:1461 [inline]
 tun_get_user+0x1c10/0x6b80 drivers/net/tun.c:1782
 tun_chr_write_iter+0x3ac/0x5d0 drivers/net/tun.c:1984
 new_sync_write fs/read_write.c:591 [inline]
 vfs_write+0xb34/0x1540 fs/read_write.c:684
 ksys_write+0x240/0x4b0 fs/read_write.c:736
 __do_sys_write fs/read_write.c:747 [inline]
 __se_sys_write fs/read_write.c:744 [inline]
 __x64_sys_write+0x93/0xe0 fs/read_write.c:744
 x64_sys_call+0x34de/0x3c80 arch/x86/include/generated/asm/syscalls_64.h:2
 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline]
 do_syscall_64+0xcd/0x1e0 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 9663 Comm: syz.4.1043 Not tainted 6.14.0-syzkaller-11270-g08733088b566 #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
=====================================================