From owner-svn-src-head@freebsd.org Fri Nov 10 18:43:14 2017 Return-Path: Delivered-To: svn-src-head@mailman.ysv.freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:1900:2254:206a::19:1]) by mailman.ysv.freebsd.org (Postfix) with ESMTP id 2A64EE73C1D; Fri, 10 Nov 2017 18:43:14 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from mail.baldwin.cx (bigwig.baldwin.cx [IPv6:2001:470:1f11:75::1]) (using TLSv1 with cipher DHE-RSA-CAMELLIA256-SHA (256/256 bits)) (Client did not present a certificate) by mx1.freebsd.org (Postfix) with ESMTPS id 0A1EE7DB16; Fri, 10 Nov 2017 18:43:14 +0000 (UTC) (envelope-from jhb@freebsd.org) Received: from ralph.baldwin.cx (c-73-231-226-104.hsd1.ca.comcast.net [73.231.226.104]) by mail.baldwin.cx (Postfix) with ESMTPSA id 7DBC310A7DB; Fri, 10 Nov 2017 13:43:12 -0500 (EST) From: John Baldwin To: src-committers@freebsd.org Cc: svn-src-all@freebsd.org, svn-src-head@freebsd.org Subject: Re: svn commit: r325624 - head/libexec/rtld-elf/mips Date: Fri, 10 Nov 2017 10:15:54 -0800 Message-ID: <6482881.6CZu26arCe@ralph.baldwin.cx> User-Agent: KMail/4.14.10 (FreeBSD/11.1-STABLE; KDE/4.14.30; amd64; ; ) In-Reply-To: <201711100117.vAA1HQqT094112@repo.freebsd.org> References: <201711100117.vAA1HQqT094112@repo.freebsd.org> MIME-Version: 1.0 Content-Transfer-Encoding: 7Bit Content-Type: text/plain; charset="us-ascii" X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.4.3 (mail.baldwin.cx); Fri, 10 Nov 2017 13:43:12 -0500 (EST) X-Virus-Scanned: clamav-milter 0.99.2 at mail.baldwin.cx X-Virus-Status: Clean X-BeenThere: svn-src-head@freebsd.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: SVN commit messages for the src tree for head/-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 10 Nov 2017 18:43:14 -0000 On Friday, November 10, 2017 01:17:26 AM John Baldwin wrote: > Author: jhb > Date: Fri Nov 10 01:17:26 2017 > New Revision: 325624 > URL: https://svnweb.freebsd.org/changeset/base/325624 > > Log: > Some fixups to the CFI directives for PLT stub entry points. > > The directives I added in r323466 and r323501 did not define a valid > CFA until several instructions into the associated functions. This > triggers an assertion in GDB when generating a stack trace while > stopped at the first instruction of PLT stub entry point since there > is no valid CFA rule for the first instruction. > > This is probably just wrong on my part as the non-simple .cfi_startproc > would have defined a valid CFA. Instead, define a valid CFA as sp + 0 > at the start of the functions and then use .cfa_def_offset to change the > offset when sp is adjusted later in the function. > > Sponsored by: DARPA / AFRL Forgot to note: also explicitly set .cfi_sections to only include unwind info in .debug_frame as none of these functions catch exceptions. -- John Baldwin