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BUG: KMSAN: uninit-value in br_nf_forward_arp+0x88a/0xea0 /net/bridge/br_netfilter_hooks.c:633
CPU: 1 PID: 12586 Comm: syz-executor.0 Not tainted 5.2.0+ #15
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+0x88a/0xea0 /net/bridge/br_netfilter_hooks.c:633
 nf_hook_entry_hookfn /./include/linux/netfilter.h:135 [inline]
 nf_hook_slow+0x18b/0x410 /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+0x1a02/0x1bd0 /net/bridge/br_input.c:164
 nf_hook_bridge_pre /net/bridge/br_input.c:247 [inline]
 br_handle_frame+0xfc3/0x1ec0 /net/bridge/br_input.c:350
 __netif_receive_skb_core+0x20a9/0x5360 /net/core/dev.c:4910
 __netif_receive_skb_one_core /net/core/dev.c:5007 [inline]
 __netif_receive_skb /net/core/dev.c:5123 [inline]
 process_backlog+0x612/0x1410 /net/core/dev.c:5934
 napi_poll /net/core/dev.c:6357 [inline]
 net_rx_action+0x738/0x1940 /net/core/dev.c:6423
 __do_softirq+0x4ad/0x858 /kernel/softirq.c:293
 do_softirq_own_stack+0x49/0x80 /arch/x86/entry/entry_64.S:1052
 </IRQ>
 do_softirq /kernel/softirq.c:338 [inline]
 __local_bh_enable_ip+0x199/0x1e0 /kernel/softirq.c:190
 local_bh_enable+0x36/0x40 /./include/linux/bottom_half.h:32
 rcu_read_unlock_bh /./include/linux/rcupdate.h:682 [inline]
 __dev_queue_xmit+0x304d/0x4270 /net/core/dev.c:3904
 dev_queue_xmit+0x4b/0x60 /net/core/dev.c:3910
 packet_snd /net/packet/af_packet.c:2941 [inline]
 packet_sendmsg+0x83f7/0x9290 /net/packet/af_packet.c:2966
 sock_sendmsg_nosec /net/socket.c:646 [inline]
 sock_sendmsg /net/socket.c:665 [inline]
 ___sys_sendmsg+0x12ff/0x13c0 /net/socket.c:2286
 __sys_sendmsg /net/socket.c:2324 [inline]
 __do_sys_sendmsg /net/socket.c:2333 [inline]
 __se_sys_sendmsg+0x305/0x460 /net/socket.c:2331
 __x64_sys_sendmsg+0x4a/0x70 /net/socket.c:2331
 do_syscall_64+0xbc/0xf0 /arch/x86/entry/common.c:302
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
RIP: 0033:0x459829
Code: fd b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 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 cb b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007eff97d4ac78 EFLAGS: 00000246 ORIG_RAX: 000000000000002e
RAX: ffffffffffffffda RBX: 0000000000000003 RCX: 0000000000459829
RDX: 0000000000000000 RSI: 0000000020000940 RDI: 0000000000000004
RBP: 000000000075bf20 R08: 0000000000000000 R09: 0000000000000000
R10: 0000000000000000 R11: 0000000000000246 R12: 00007eff97d4b6d4
R13: 00000000004c7560 R14: 00000000004dcac0 R15: 00000000ffffffff

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:2771 [inline]
 __kmalloc_node_track_caller+0xc8f/0xf10 /mm/slub.c:4389
 __kmalloc_reserve /net/core/skbuff.c:138 [inline]
 __alloc_skb+0x306/0xa10 /net/core/skbuff.c:206
 alloc_skb /./include/linux/skbuff.h:1055 [inline]
 alloc_skb_with_frags+0x18c/0xa80 /net/core/skbuff.c:5328
 sock_alloc_send_pskb+0xafd/0x10a0 /net/core/sock.c:2219
 packet_alloc_skb /net/packet/af_packet.c:2789 [inline]
 packet_snd /net/packet/af_packet.c:2884 [inline]
 packet_sendmsg+0x6627/0x9290 /net/packet/af_packet.c:2966
 sock_sendmsg_nosec /net/socket.c:646 [inline]
 sock_sendmsg /net/socket.c:665 [inline]
 ___sys_sendmsg+0x12ff/0x13c0 /net/socket.c:2286
 __sys_sendmsg /net/socket.c:2324 [inline]
 __do_sys_sendmsg /net/socket.c:2333 [inline]
 __se_sys_sendmsg+0x305/0x460 /net/socket.c:2331
 __x64_sys_sendmsg+0x4a/0x70 /net/socket.c:2331
 do_syscall_64+0xbc/0xf0 /arch/x86/entry/common.c:302
 entry_SYSCALL_64_after_hwframe+0x63/0xe7
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