==================================================================
BUG: KMSAN: uninit-value in fib_rule_port_inrange include/net/fib_rules.h:162 [inline]
BUG: KMSAN: uninit-value in fib4_rule_match+0x6eb/0x740 net/ipv4/fib_rules.c:189
CPU: 0 PID: 14527 Comm: syz-executor6 Not tainted 4.17.0-rc3+ #94
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+0x185/0x1d0 lib/dump_stack.c:113
 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1084
 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683
 fib_rule_port_inrange include/net/fib_rules.h:162 [inline]
 fib4_rule_match+0x6eb/0x740 net/ipv4/fib_rules.c:189
 fib_rule_match net/core/fib_rules.c:273 [inline]
 fib_rules_lookup+0xb0c/0xe50 net/core/fib_rules.c:288
 __fib_lookup+0x1bc/0x360 net/ipv4/fib_rules.c:93
 fib_lookup include/net/ip_fib.h:322 [inline]
 __fib_validate_source net/ipv4/fib_frontend.c:353 [inline]
 fib_validate_source+0xc23/0x1d50 net/ipv4/fib_frontend.c:434
 ip_mc_validate_source net/ipv4/route.c:1567 [inline]
 ip_route_input_mc net/ipv4/route.c:1585 [inline]
 ip_route_input_rcu+0x1fd6/0x66d0 net/ipv4/route.c:2149
IPv4: Oversized IP packet from 127.0.0.1
 ip_route_input_noref+0x10e/0x140 net/ipv4/route.c:2101
 ip_rcv_finish+0x631/0x1d00 net/ipv4/ip_input.c:347
 NF_HOOK include/linux/netfilter.h:288 [inline]
 ip_rcv+0x118f/0x16d0 net/ipv4/ip_input.c:492
 __netif_receive_skb_core+0x47df/0x4a90 net/core/dev.c:4592
 __netif_receive_skb net/core/dev.c:4657 [inline]
 netif_receive_skb_internal+0x49d/0x630 net/core/dev.c:4731
 netif_receive_skb+0x230/0x240 net/core/dev.c:4755
 tun_rx_batched drivers/net/tun.c:1558 [inline]
 tun_get_user+0x6b67/0x7e40 drivers/net/tun.c:1962
 tun_chr_write_iter+0x1d4/0x330 drivers/net/tun.c:1990
 do_iter_readv_writev+0x84d/0xa00 include/linux/fs.h:1778
 do_iter_write+0x30d/0xd40 fs/read_write.c:959
 vfs_writev fs/read_write.c:1004 [inline]
 do_writev+0x3c9/0x830 fs/read_write.c:1039
 __do_sys_writev fs/read_write.c:1112 [inline]
 __se_sys_writev fs/read_write.c:1109 [inline]
 __x64_sys_writev+0xe1/0x120 fs/read_write.c:1109
 do_syscall_64+0x154/0x220 arch/x86/entry/common.c:287
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x4558c1
RSP: 002b:00007ff61ab5fba0 EFLAGS: 00000293 ORIG_RAX: 0000000000000014
RAX: ffffffffffffffda RBX: 000000000000fed1 RCX: 00000000004558c1
RDX: 0000000000000001 RSI: 00007ff61ab5fbf0 RDI: 00000000000000fc
RBP: 000000002000a000 R08: 00000000000000fc R09: 0000000000000000
R10: 000000000000fed1 R11: 0000000000000293 R12: 00000000ffffffff
R13: 0000000000000712 R14: 00000000006fea50 R15: 0000000000000000

Local variable description: ----fl4.i@fib_validate_source
Variable was created at:
 fib_validate_source+0x127/0x1d50 net/ipv4/fib_frontend.c:410
 ip_mc_validate_source net/ipv4/route.c:1567 [inline]
 ip_route_input_mc net/ipv4/route.c:1585 [inline]
 ip_route_input_rcu+0x1fd6/0x66d0 net/ipv4/route.c:2149
==================================================================