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BUG: KMSAN: uninit-value in bpf_prog_run_generic_xdp+0x190b/0x1f20 net/core/dev.c:5202
 bpf_prog_run_generic_xdp+0x190b/0x1f20 net/core/dev.c:5202
 netif_receive_generic_xdp net/core/dev.c:5284 [inline]
 do_xdp_generic+0xc10/0x15a0 net/core/dev.c:5346
 tun_get_user+0x4aff/0x6a50 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]
 __ia32_sys_write+0x91/0xe0 fs/read_write.c:744
 ia32_sys_call+0x2e7b/0x41f0 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+0xb0/0x110 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 stored to memory at:
 pskb_expand_head+0x33a/0x1c10 net/core/skbuff.c:2255
 netif_skb_check_for_xdp net/core/dev.c:5247 [inline]
 netif_receive_generic_xdp net/core/dev.c:5278 [inline]
 do_xdp_generic+0x9e6/0x15a0 net/core/dev.c:5346
 tun_get_user+0x4aff/0x6a50 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]
 __ia32_sys_write+0x91/0xe0 fs/read_write.c:744
 ia32_sys_call+0x2e7b/0x41f0 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+0xb0/0x110 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:4157 [inline]
 slab_alloc_node mm/slub.c:4200 [inline]
 __do_kmalloc_node mm/slub.c:4330 [inline]
 __kmalloc_node_track_caller_noprof+0x962/0x1260 mm/slub.c:4350
 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:2954
 tun_alloc_skb drivers/net/tun.c:1461 [inline]
 tun_get_user+0x1c19/0x6a50 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]
 __ia32_sys_write+0x91/0xe0 fs/read_write.c:744
 ia32_sys_call+0x2e7b/0x41f0 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+0xb0/0x110 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

CPU: 0 UID: 0 PID: 17085 Comm: syz.5.3103 Not tainted 6.15.0-rc2-syzkaller #0 PREEMPT(undef) 
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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