Hello, syzbot hit the following crash on https://github.com/google/kmsan.git/master commit a7f95e9c8a95e9fbb388c3999b61a17667cd3bbe (Sat Apr 21 13:50:22 2018 +0000) kmsan: disable assembly checksums syzbot dashboard link: https://syzkaller.appspot.com/bug?extid=5c06e318fc558cc27823 So far this crash happened 3 times on https://github.com/google/kmsan.git/master. C reproducer: https://syzkaller.appspot.com/x/repro.c?id=5411555638247424 syzkaller reproducer: https://syzkaller.appspot.com/x/repro.syz?id=6309829995921408 Raw console output: https://syzkaller.appspot.com/x/log.txt?id=4546610964987904 Kernel config: https://syzkaller.appspot.com/x/.config?id=328654897048964367 compiler: clang version 7.0.0 (trunk 329391) IMPORTANT: if you fix the bug, please add the following tag to the commit: Reported-by: syzbot+5c06e318fc558cc27823 at syzkaller.appspotmail.com It will help syzbot understand when the bug is fixed. See footer for details. If you forward the report, please keep this part and the footer. =================================================================BUG: KMSAN: uninit-value in ebt_stp_mt_check+0x248/0x410 net/bridge/netfilter/ebt_stp.c:164 CPU: 0 PID: 4520 Comm: syzkaller565841 Not tainted 4.16.0+ #85 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x185/0x1d0 lib/dump_stack.c:53 kmsan_report+0x142/0x240 mm/kmsan/kmsan.c:1067 __msan_warning_32+0x6c/0xb0 mm/kmsan/kmsan_instr.c:683 ebt_stp_mt_check+0x248/0x410 net/bridge/netfilter/ebt_stp.c:164 xt_check_match+0x1449/0x1660 net/netfilter/x_tables.c:499 ebt_check_match net/bridge/netfilter/ebtables.c:374 [inline] ebt_check_entry net/bridge/netfilter/ebtables.c:704 [inline] translate_table+0x3ffd/0x5e10 net/bridge/netfilter/ebtables.c:945 do_replace_finish+0x1258/0x2ea0 net/bridge/netfilter/ebtables.c:1002 do_replace+0x707/0x770 net/bridge/netfilter/ebtables.c:1141 do_ebt_set_ctl+0x2ab/0x3c0 net/bridge/netfilter/ebtables.c:1518 nf_sockopt net/netfilter/nf_sockopt.c:106 [inline] nf_setsockopt+0x476/0x4d0 net/netfilter/nf_sockopt.c:115 ip_setsockopt+0x24b/0x2b0 net/ipv4/ip_sockglue.c:1261 dccp_setsockopt+0x1c3/0x1f0 net/dccp/proto.c:576 sock_common_setsockopt+0x136/0x170 net/core/sock.c:2975 SYSC_setsockopt+0x4b8/0x570 net/socket.c:1849 SyS_setsockopt+0x76/0xa0 net/socket.c:1828 do_syscall_64+0x309/0x430 arch/x86/entry/common.c:287 entry_SYSCALL_64_after_hwframe+0x3d/0xa2 RIP: 0033:0x445d39 RSP: 002b:00007efff4e14da8 EFLAGS: 00000246 ORIG_RAX: 0000000000000036 RAX: ffffffffffffffda RBX: 00000000006dac24 RCX: 0000000000445d39 RDX: 0000000000000080 RSI: 0000000000000000 RDI: 0000000000000003 RBP: 0000000000000000 R08: 0000000000000358 R09: 0000000000000000 R10: 00000000200008c0 R11: 0000000000000246 R12: 00000000006dac20 R13: 006567646972625f R14: 6f745f3168746576 R15: 0000000000000002 Local variable description: ----mtpar.i at translate_table Variable was created at: translate_table+0xb9/0x5e10 net/bridge/netfilter/ebtables.c:833 do_replace_finish+0x1258/0x2ea0 net/bridge/netfilter/ebtables.c:1002 ================================================================= --- This bug is generated by a dumb bot. It may contain errors. See https://goo.gl/tpsmEJ for details. Direct all questions to syzkaller at googlegroups.com. syzbot will keep track of this bug report. If you forgot to add the Reported-by tag, once the fix for this bug is merged into any tree, please reply to this email with: #syz fix: exact-commit-title If you want to test a patch for this bug, please reply with: #syz test: git://repo/address.git branch and provide the patch inline or as an attachment. To mark this as a duplicate of another syzbot report, please reply with: #syz dup: exact-subject-of-another-report If it's a one-off invalid bug report, please reply with: #syz invalid Note: if the crash happens again, it will cause creation of a new bug report. Note: all commands must start from beginning of the line in the email body.