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BUG: KMSAN: uninit-value in br_nf_forward_arp+0xe61/0x1230 net/bridge/br_netfilter_hooks.c:661
CPU: 1 PID: 11746 Comm: syz-executor223 Not tainted 5.3.0-rc6+ #19
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 <IRQ>
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x191/0x1f0 lib/dump_stack.c:113
 kmsan_report+0x162/0x2d0 mm/kmsan/kmsan_report.c:109
 __msan_warning+0x75/0xe0 mm/kmsan/kmsan_instr.c:294
 br_nf_forward_arp+0xe61/0x1230 net/bridge/br_netfilter_hooks.c:661
 nf_hook_entry_hookfn include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0x18b/0x3f0 net/netfilter/core.c:512
 nf_hook include/linux/netfilter.h:260 [inline]
 NF_HOOK include/linux/netfilter.h:303 [inline]
 __br_forward+0x78f/0xe30 net/bridge/br_forward.c:109
 br_flood+0xef0/0xfe0 net/bridge/br_forward.c:234
 br_handle_frame_finish+0x1a77/0x1c20 net/bridge/br_input.c:162
 nf_hook_bridge_pre net/bridge/br_input.c:245 [inline]
 br_handle_frame+0xfb6/0x1eb0 net/bridge/br_input.c:348
 __netif_receive_skb_core+0x20b9/0x51a0 net/core/dev.c:4905
 __netif_receive_skb_one_core net/core/dev.c:5002 [inline]
 __netif_receive_skb net/core/dev.c:5118 [inline]
 process_backlog+0x612/0x1410 net/core/dev.c:5929
 napi_poll net/core/dev.c:6352 [inline]
 net_rx_action+0x74b/0x1950 net/core/dev.c:6418
 __do_softirq+0x4a1/0x83a kernel/softirq.c:293
 do_softirq_own_stack+0x49/0x80 arch/x86/entry/entry_64.S:1093
 </IRQ>
 do_softirq kernel/softirq.c:338 [inline]
 __local_bh_enable_ip+0x184/0x1d0 kernel/softirq.c:190
 local_bh_enable+0x36/0x40 include/linux/bottom_half.h:32
 rcu_read_unlock_bh include/linux/rcupdate.h:681 [inline]
 __dev_queue_xmit+0x304d/0x4270 net/core/dev.c:3896
 dev_queue_xmit+0x4b/0x60 net/core/dev.c:3902
 packet_snd net/packet/af_packet.c:2959 [inline]
 packet_sendmsg+0x82d7/0x92e0 net/packet/af_packet.c:2984
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg net/socket.c:657 [inline]
 ___sys_sendmsg+0x14ff/0x1590 net/socket.c:2311
 __sys_sendmmsg+0x53a/0xae0 net/socket.c:2413
 __do_sys_sendmmsg net/socket.c:2442 [inline]
 __se_sys_sendmmsg+0xbd/0xe0 net/socket.c:2439
 __x64_sys_sendmmsg+0x56/0x70 net/socket.c:2439
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x441ae9
Code: 18 89 d0 c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 7b 10 fc ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007fffe70a5e48 EFLAGS: 00000246 ORIG_RAX: 0000000000000133
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000441ae9
RDX: 0000000000000001 RSI: 0000000020004e80 RDI: 0000000000000004
RBP: 00007fffe70a5e60 R08: 0000000001bbbbbb R09: 0000000001bbbbbb
R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
R13: 0000000000403080 R14: 0000000000000000 R15: 0000000000000000

Uninit was created at:
 kmsan_save_stack_with_flags mm/kmsan/kmsan.c:187 [inline]
 kmsan_internal_poison_shadow+0x53/0xa0 mm/kmsan/kmsan.c:146
 kmsan_slab_alloc+0xaa/0x120 mm/kmsan/kmsan_hooks.c:175
 slab_alloc_node mm/slub.c:2790 [inline]
 __kmalloc_node_track_caller+0xb55/0x1320 mm/slub.c:4388
 __kmalloc_reserve net/core/skbuff.c:141 [inline]
 __alloc_skb+0x306/0xa10 net/core/skbuff.c:209
 alloc_skb include/linux/skbuff.h:1056 [inline]
 alloc_skb_with_frags+0x18c/0xa80 net/core/skbuff.c:5628
 sock_alloc_send_pskb+0xafd/0x10a0 net/core/sock.c:2232
 packet_alloc_skb net/packet/af_packet.c:2807 [inline]
 packet_snd net/packet/af_packet.c:2902 [inline]
 packet_sendmsg+0x6785/0x92e0 net/packet/af_packet.c:2984
 sock_sendmsg_nosec net/socket.c:637 [inline]
 sock_sendmsg net/socket.c:657 [inline]
 ___sys_sendmsg+0x14ff/0x1590 net/socket.c:2311
 __sys_sendmmsg+0x53a/0xae0 net/socket.c:2413
 __do_sys_sendmmsg net/socket.c:2442 [inline]
 __se_sys_sendmmsg+0xbd/0xe0 net/socket.c:2439
 __x64_sys_sendmmsg+0x56/0x70 net/socket.c:2439
 do_syscall_64+0xbc/0xf0 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
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