From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS4713 221.184.0.0/13 X-Spam-Status: No, score=-3.9 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,RCVD_IN_DNSWL_MED, SPF_HELO_NONE,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from neon.ruby-lang.org (neon.ruby-lang.org [221.186.184.75]) by dcvr.yhbt.net (Postfix) with ESMTP id 776571F463 for ; Thu, 26 Sep 2019 13:18:35 +0000 (UTC) Received: from neon.ruby-lang.org (localhost [IPv6:::1]) by neon.ruby-lang.org (Postfix) with ESMTP id EBA92120B91; Thu, 26 Sep 2019 22:18:26 +0900 (JST) Received: from o1678948x4.outbound-mail.sendgrid.net (o1678948x4.outbound-mail.sendgrid.net [167.89.48.4]) by neon.ruby-lang.org (Postfix) with ESMTPS id 35754120B61 for ; Thu, 26 Sep 2019 22:18:22 +0900 (JST) Received: by filter0113p3las1.sendgrid.net with SMTP id filter0113p3las1-7170-5D8CBAA0-D 2019-09-26 13:18:24.098781546 +0000 UTC m=+237701.827099565 Received: from herokuapp.com (unknown [34.207.207.12]) by ismtpd0065p1mdw1.sendgrid.net (SG) with ESMTP id z5CVn7POQJa8SYg0xtJs_Q for ; Thu, 26 Sep 2019 13:18:23.948 +0000 (UTC) Date: Thu, 26 Sep 2019 13:18:24 +0000 (UTC) From: iv@altlinux.org Message-ID: References: Mime-Version: 1.0 X-Redmine-MailingListIntegration-Message-Ids: 70660 X-Redmine-Project: ruby-trunk X-Redmine-Issue-Id: 16184 X-Redmine-Issue-Author: iv-m X-Redmine-Sender: iv-m X-Mailer: Redmine X-Redmine-Host: bugs.ruby-lang.org X-Redmine-Site: Ruby Issue Tracking System X-Auto-Response-Suppress: All Auto-Submitted: auto-generated X-SG-EID: =?us-ascii?Q?WfYseQ1RardbWxw=2FdWWhetV1CqQcnZYCD6ZOQJG8UaAHTG5U+K0YHDrycg+KKv?= =?us-ascii?Q?U1XaJMO1nDp3zAiSk2r7+9RHunhgwIpvFNgO06k?= =?us-ascii?Q?pH1PUK7Gp7YrBBdrK3Nt2pr0M2zzLfM7EmXIXtE?= =?us-ascii?Q?X6M=2F9Gx+JyAihEsxHh45z0=2FY4h5Rbnakatj8gG5?= =?us-ascii?Q?ztdsve6fsn4VY?= To: ruby-core@ruby-lang.org X-ML-Name: ruby-core X-Mail-Count: 95105 Subject: [ruby-core:95105] [Ruby master Bug#16184] Entry persists in catch table even though its labels were removed, which may cause [BUG] X-BeenThere: ruby-core@ruby-lang.org X-Mailman-Version: 2.1.15 Precedence: list Reply-To: Ruby developers List-Id: Ruby developers List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: ruby-core-bounces@ruby-lang.org Sender: "ruby-core" Issue #16184 has been reported by iv-m (Ivan Melnikov). ---------------------------------------- Bug #16184: Entry persists in catch table even though its labels were removed, which may cause [BUG] https://bugs.ruby-lang.org/issues/16184 * Author: iv-m (Ivan Melnikov) * Status: Open * Priority: Normal * Assignee: * Target version: * ruby -v: ruby 2.5.5p157 (2019-03-15) [mipsel-linux] * Backport: 2.5: UNKNOWN, 2.6: UNKNOWN ---------------------------------------- When `remove_unreachable_chunk` removes the code from within a rescue block, the catch table entry corresponding the block is not removed. Here is a simple reproducer (tested with ruby 2.5.5): ``` ruby puts "BEGIN" if false begin require "some_mad_stuff" rescue LoadError puts "no mad stuff loaded" end end puts "END" ``` Here is the corresponding disasm: ``` == disasm: #@test2.rb:1 (1,0)-(12,10)>====================== == catch table | catch type: rescue st: 11022376 ed: 11022516 sp: -002 cont: 0000 == disasm: #@test2.rb:7 (7,2)-(9,2)>============== local table (size: 1, argc: 0 [opts: 0, rest: -1, post: 0, block: -1, kw: -1@-1, kwrest: -1]) [ 1] "\#$!" 0000 getlocal_OP__WC__0 "\#$!" ( 7) 0002 getinlinecache 9, 0005 getconstant :LoadError 0007 setinlinecache 0009 checkmatch 3 0011 branchunless 20 0013 putself ( 8)[Li] 0014 putstring "no mad stuff loaded" 0016 opt_send_without_block , 0019 leave ( 7) 0020 getlocal_OP__WC__0 "\#$!" 0022 throw 0 | catch type: retry st: 11022516 ed: 0000 sp: -001 cont: 11022376 |------------------------------------------------------------------------ 0000 putself ( 2)[Li] 0001 putstring "BEGIN" 0003 opt_send_without_block , 0006 pop 0007 putself ( 12)[Li] 0008 putstring "END" 0010 opt_send_without_block , 0013 leave ``` The interesting line here is: ``` catch type: rescue st: 11022376 ed: 11022516 sp: -002 cont: 0000 ``` As the instruction corresponding the `begin..rescue` block were optimized away, the `sp` filed of the continue label was still -1 (or -2) and `position`s of start, end and continue labels are never initialized. When any exception happens in the remaining code (requires a bit more complex reproducer, happens in real life), this may cause an interpreter to segfault. I've discovered this issue when building net-scp gem, which has this `if false; require` pattern in its Rakefile: https://github.com/net-ssh/net-scp/blob/v2.0.0/Rakefile . Interpreter reproducibly segfaults when trying to run it on my MIPS32 LE machine. -- https://bugs.ruby-lang.org/