syzbot

=====================================================
BUG: KMSAN: uninit-value in netif_skb_features+0x115b/0x2160 net/core/dev.c:3833
 netif_skb_features+0x115b/0x2160 net/core/dev.c:3833
 validate_xmit_skb+0xb6/0x2400 net/core/dev.c:3993
 __dev_queue_xmit+0x172a/0x58e0 net/core/dev.c:4811
 dev_queue_xmit include/linux/netdevice.h:3381 [inline]
 br_dev_queue_push_xmit+0xa12/0xc20 net/bridge/br_forward.c:53
 NF_HOOK include/linux/netfilter.h:318 [inline]
 br_forward_finish+0xfe/0x330 net/bridge/br_forward.c:66
 NF_HOOK include/linux/netfilter.h:318 [inline]
 __br_forward+0x847/0xab0 net/bridge/br_forward.c:115
 deliver_clone net/bridge/br_forward.c:131 [inline]
 maybe_deliver+0x3e0/0x5c0 net/bridge/br_forward.c:191
 br_flood+0x45b/0xb70 net/bridge/br_forward.c:238
 br_handle_frame_finish+0x2a34/0x2dd0 net/bridge/br_input.c:229
 nf_hook_bridge_pre net/bridge/br_input.c:313 [inline]
 br_handle_frame+0x179f/0x2180 net/bridge/br_input.c:442
 __netif_receive_skb_core+0xf8c/0x4d10 net/core/dev.c:6026
 __netif_receive_skb_list_core+0x2f1/0x16b0 net/core/dev.c:6214
 __netif_receive_skb_list net/core/dev.c:6281 [inline]
 netif_receive_skb_list_internal+0xee7/0x1530 net/core/dev.c:6372
 gro_normal_list include/net/gro.h:524 [inline]
 gro_flush_normal include/net/gro.h:532 [inline]
 napi_complete_done+0x403/0x790 net/core/dev.c:6741
 gro_cell_poll+0x2c9/0x310 net/core/gro_cells.c:74
 __napi_poll+0xd8/0x880 net/core/dev.c:7668
 napi_poll net/core/dev.c:7731 [inline]
 net_rx_action+0xa3f/0x1c90 net/core/dev.c:7883
 handle_softirqs+0x169/0x6e0 kernel/softirq.c:622
 __do_softirq+0x14/0x1b kernel/softirq.c:656
 do_softirq+0x58/0x90 kernel/softirq.c:523
 __local_bh_enable_ip+0xa1/0xb0 kernel/softirq.c:450
 local_bh_enable include/linux/bottom_half.h:33 [inline]
 tun_rx_batched+0x889/0x980 drivers/net/tun.c:-1
 tun_get_user+0x5c0e/0x6c60 drivers/net/tun.c:1953
 tun_chr_write_iter+0x3e9/0x5c0 drivers/net/tun.c:1999
 new_sync_write fs/read_write.c:593 [inline]
 vfs_write+0xbe2/0x15d0 fs/read_write.c:686
 ksys_write fs/read_write.c:738 [inline]
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x1fb/0x4d0 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+0xd3/0xf80 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]
 kmem_cache_alloc_node_noprof+0x9e7/0x17a0 mm/slub.c:5315
 kmalloc_reserve+0x13c/0x4b0 net/core/skbuff.c:586
 __alloc_skb+0x805/0x1040 net/core/skbuff.c:690
 alloc_skb include/linux/skbuff.h:1383 [inline]
 alloc_skb_with_frags+0xc5/0xa60 net/core/skbuff.c:6712
 sock_alloc_send_pskb+0xacc/0xc60 net/core/sock.c:2995
 tun_alloc_skb drivers/net/tun.c:1461 [inline]
 tun_get_user+0x1142/0x6c60 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+0xbe2/0x15d0 fs/read_write.c:686
 ksys_write fs/read_write.c:738 [inline]
 __do_sys_write fs/read_write.c:749 [inline]
 __se_sys_write fs/read_write.c:746 [inline]
 __x64_sys_write+0x1fb/0x4d0 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+0xd3/0xf80 arch/x86/entry/syscall_64.c:94
 entry_SYSCALL_64_after_hwframe+0x77/0x7f

CPU: 0 UID: 0 PID: 9405 Comm: syz.4.740 Tainted: G             L      syzkaller #0 PREEMPT(none) 
Tainted: [L]=SOFTLOCKUP
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/25/2025
=====================================================