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BUG: KMSAN: uninit-value in bpf_prog_run_generic_xdp+0x190a/0x1f20 net/core/dev.c:5219
 bpf_prog_run_generic_xdp+0x190a/0x1f20 net/core/dev.c:5219
 netif_receive_generic_xdp net/core/dev.c:5301 [inline]
 do_xdp_generic+0xc0d/0x15a0 net/core/dev.c:5363
 tun_get_user+0x4952/0x6e50 drivers/net/tun.c:1929
 tun_chr_write_iter+0x3ac/0x5d0 drivers/net/tun.c:2053
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0xb34/0x1540 fs/read_write.c:679
 ksys_write+0x240/0x4b0 fs/read_write.c:731
 __do_sys_write fs/read_write.c:742 [inline]
 __se_sys_write fs/read_write.c:739 [inline]
 __ia32_sys_write+0x91/0xe0 fs/read_write.c:739
 ia32_sys_call+0x2f4b/0x4180 arch/x86/include/generated/asm/syscalls_32.h:5
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0xb0/0x110 arch/x86/entry/common.c:387
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/common.c:412
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:450
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Uninit was stored to memory at:
 pskb_expand_head+0x33a/0x1b70 net/core/skbuff.c:2193
 netif_skb_check_for_xdp net/core/dev.c:5264 [inline]
 netif_receive_generic_xdp net/core/dev.c:5295 [inline]
 do_xdp_generic+0x9e3/0x15a0 net/core/dev.c:5363
 tun_get_user+0x4952/0x6e50 drivers/net/tun.c:1929
 tun_chr_write_iter+0x3ac/0x5d0 drivers/net/tun.c:2053
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0xb34/0x1540 fs/read_write.c:679
 ksys_write+0x240/0x4b0 fs/read_write.c:731
 __do_sys_write fs/read_write.c:742 [inline]
 __se_sys_write fs/read_write.c:739 [inline]
 __ia32_sys_write+0x91/0xe0 fs/read_write.c:739
 ia32_sys_call+0x2f4b/0x4180 arch/x86/include/generated/asm/syscalls_32.h:5
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0xb0/0x110 arch/x86/entry/common.c:387
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/common.c:412
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:450
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

Uninit was created at:
 slab_post_alloc_hook mm/slub.c:4121 [inline]
 slab_alloc_node mm/slub.c:4164 [inline]
 __do_kmalloc_node mm/slub.c:4293 [inline]
 __kmalloc_node_track_caller_noprof+0x945/0x1240 mm/slub.c:4313
 kmalloc_reserve+0x23e/0x4a0 net/core/skbuff.c:537
 __alloc_skb+0x363/0x7b0 net/core/skbuff.c:606
 alloc_skb include/linux/skbuff.h:1331 [inline]
 alloc_skb_with_frags+0xc8/0xd00 net/core/skbuff.c:6522
 sock_alloc_send_pskb+0xa81/0xbf0 net/core/sock.c:2914
 tun_alloc_skb drivers/net/tun.c:1526 [inline]
 tun_get_user+0x1c6d/0x6e50 drivers/net/tun.c:1851
 tun_chr_write_iter+0x3ac/0x5d0 drivers/net/tun.c:2053
 new_sync_write fs/read_write.c:586 [inline]
 vfs_write+0xb34/0x1540 fs/read_write.c:679
 ksys_write+0x240/0x4b0 fs/read_write.c:731
 __do_sys_write fs/read_write.c:742 [inline]
 __se_sys_write fs/read_write.c:739 [inline]
 __ia32_sys_write+0x91/0xe0 fs/read_write.c:739
 ia32_sys_call+0x2f4b/0x4180 arch/x86/include/generated/asm/syscalls_32.h:5
 do_syscall_32_irqs_on arch/x86/entry/common.c:165 [inline]
 __do_fast_syscall_32+0xb0/0x110 arch/x86/entry/common.c:387
 do_fast_syscall_32+0x38/0x80 arch/x86/entry/common.c:412
 do_SYSENTER_32+0x1f/0x30 arch/x86/entry/common.c:450
 entry_SYSENTER_compat_after_hwframe+0x84/0x8e

CPU: 0 UID: 0 PID: 7605 Comm: syz.6.336 Not tainted 6.14.0-rc4-syzkaller-00295-gb91872c56940 #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 02/12/2025
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