===================================================== BUG: KMSAN: uninit-value in packet_rcv_fanout+0x2442/0x25c0 net/packet/af_packet.c:1463 CPU: 1 PID: 22191 Comm: syz-executor.3 Not tainted 5.7.0-rc4-syzkaller #0 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:77 [inline] dump_stack+0x1c9/0x220 lib/dump_stack.c:118 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215 packet_rcv_fanout+0x2442/0x25c0 net/packet/af_packet.c:1463 dev_queue_xmit_nit+0x1199/0x1270 net/core/dev.c:2276 xmit_one net/core/dev.c:3473 [inline] dev_hard_start_xmit+0x20f/0xab0 net/core/dev.c:3493 __dev_queue_xmit+0x2f8d/0x3b20 net/core/dev.c:4052 dev_queue_xmit+0x4b/0x60 net/core/dev.c:4085 neigh_hh_output include/net/neighbour.h:499 [inline] neigh_output include/net/neighbour.h:508 [inline] ip_finish_output2+0x20fd/0x2610 net/ipv4/ip_output.c:228 __ip_finish_output+0xaa7/0xd80 net/ipv4/ip_output.c:306 ip_finish_output+0x166/0x410 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_output+0x593/0x680 net/ipv4/ip_output.c:430 dst_output include/net/dst.h:435 [inline] ip_local_out net/ipv4/ip_output.c:125 [inline] ip_send_skb+0x179/0x360 net/ipv4/ip_output.c:1560 udp_send_skb+0x1046/0x18b0 net/ipv4/udp.c:891 udp_sendmsg+0x3bb5/0x4100 net/ipv4/udp.c:1178 inet_sendmsg+0x276/0x2e0 net/ipv4/af_inet.c:807 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg net/socket.c:672 [inline] ____sys_sendmsg+0x1056/0x1350 net/socket.c:2362 ___sys_sendmsg net/socket.c:2416 [inline] __sys_sendmmsg+0x5fe/0xd60 net/socket.c:2506 __do_sys_sendmmsg net/socket.c:2535 [inline] __se_sys_sendmmsg+0xbd/0xe0 net/socket.c:2532 __x64_sys_sendmmsg+0x56/0x70 net/socket.c:2532 do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x44/0xa9 RIP: 0033:0x45ca29 Code: 0d 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 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00 RSP: 002b:00007f8b58949c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000133 RAX: ffffffffffffffda RBX: 00000000004fc580 RCX: 000000000045ca29 RDX: 04000000000001a8 RSI: 0000000020007fc0 RDI: 0000000000000003 RBP: 000000000078bfa0 R08: 0000000000000000 R09: 0000000000000000 R10: 0000000000000000 R11: 0000000000000246 R12: 00000000ffffffff R13: 00000000000008dd R14: 00000000004cba1f R15: 00007f8b5894a6d4 Uninit was stored to memory at: kmsan_save_stack_with_flags mm/kmsan/kmsan.c:144 [inline] kmsan_internal_chain_origin+0xad/0x130 mm/kmsan/kmsan.c:310 __msan_chain_origin+0x50/0x90 mm/kmsan/kmsan_instr.c:165 ___bpf_prog_run+0x6c64/0x97a0 kernel/bpf/core.c:1391 __bpf_prog_run32+0x101/0x170 kernel/bpf/core.c:1681 bpf_dispatcher_nop_func include/linux/bpf.h:545 [inline] bpf_prog_run_pin_on_cpu include/linux/filter.h:599 [inline] bpf_prog_run_clear_cb include/linux/filter.h:721 [inline] fanout_demux_bpf net/packet/af_packet.c:1404 [inline] packet_rcv_fanout+0x51e/0x25c0 net/packet/af_packet.c:1456 dev_queue_xmit_nit+0x1199/0x1270 net/core/dev.c:2276 xmit_one net/core/dev.c:3473 [inline] dev_hard_start_xmit+0x20f/0xab0 net/core/dev.c:3493 __dev_queue_xmit+0x2f8d/0x3b20 net/core/dev.c:4052 dev_queue_xmit+0x4b/0x60 net/core/dev.c:4085 neigh_hh_output include/net/neighbour.h:499 [inline] neigh_output include/net/neighbour.h:508 [inline] ip_finish_output2+0x20fd/0x2610 net/ipv4/ip_output.c:228 __ip_finish_output+0xaa7/0xd80 net/ipv4/ip_output.c:306 ip_finish_output+0x166/0x410 net/ipv4/ip_output.c:316 NF_HOOK_COND include/linux/netfilter.h:296 [inline] ip_output+0x593/0x680 net/ipv4/ip_output.c:430 dst_output include/net/dst.h:435 [inline] ip_local_out net/ipv4/ip_output.c:125 [inline] ip_send_skb+0x179/0x360 net/ipv4/ip_output.c:1560 udp_send_skb+0x1046/0x18b0 net/ipv4/udp.c:891 udp_sendmsg+0x3bb5/0x4100 net/ipv4/udp.c:1178 inet_sendmsg+0x276/0x2e0 net/ipv4/af_inet.c:807 sock_sendmsg_nosec net/socket.c:652 [inline] sock_sendmsg net/socket.c:672 [inline] ____sys_sendmsg+0x1056/0x1350 net/socket.c:2362 ___sys_sendmsg net/socket.c:2416 [inline] __sys_sendmmsg+0x5fe/0xd60 net/socket.c:2506 __do_sys_sendmmsg net/socket.c:2535 [inline] __se_sys_sendmmsg+0xbd/0xe0 net/socket.c:2532 __x64_sys_sendmmsg+0x56/0x70 net/socket.c:2532 do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:297 entry_SYSCALL_64_after_hwframe+0x44/0xa9 Local variable ----regs@__bpf_prog_run32 created at: __bpf_prog_run32+0x87/0x170 kernel/bpf/core.c:1681 __bpf_prog_run32+0x87/0x170 kernel/bpf/core.c:1681 =====================================================