From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 22608 invoked by alias); 5 Oct 2014 16:43:55 -0000 Mailing-List: contact gdb-patches-help@sourceware.org; run by ezmlm Precedence: bulk List-Id: List-Subscribe: List-Archive: List-Post: List-Help: , Sender: gdb-patches-owner@sourceware.org Received: (qmail 22589 invoked by uid 89); 5 Oct 2014 16:43:53 -0000 Authentication-Results: sourceware.org; auth=none X-Virus-Found: No X-Spam-SWARE-Status: No, score=-4.0 required=5.0 tests=AWL,BAYES_00,SPF_HELO_PASS,SPF_PASS,T_RP_MATCHES_RCVD autolearn=ham version=3.3.2 X-HELO: mx1.redhat.com Received: from mx1.redhat.com (HELO mx1.redhat.com) (209.132.183.28) by sourceware.org (qpsmtpd/0.93/v0.84-503-g423c35a) with (AES256-GCM-SHA384 encrypted) ESMTPS; Sun, 05 Oct 2014 16:43:52 +0000 Received: from int-mx14.intmail.prod.int.phx2.redhat.com (int-mx14.intmail.prod.int.phx2.redhat.com [10.5.11.27]) by mx1.redhat.com (8.14.4/8.14.4) with ESMTP id s95Gho4v004972 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=FAIL) for ; Sun, 5 Oct 2014 12:43:51 -0400 Received: from host2.jankratochvil.net (ovpn-116-49.ams2.redhat.com [10.36.116.49]) by int-mx14.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id s95Ghlol000923 (version=TLSv1/SSLv3 cipher=AES128-GCM-SHA256 bits=128 verify=NO); Sun, 5 Oct 2014 12:43:49 -0400 Date: Sun, 05 Oct 2014 16:43:00 -0000 From: Jan Kratochvil To: Pedro Alves Cc: gdb-patches@sourceware.org Subject: Re: Crash regression for annota1.exp w/vDSO debuginfo [Re: [pushed] Re: [PATCH v6 0/2] enable target-async by default] Message-ID: <20141005164346.GA25654@host2.jankratochvil.net> References: <1400878753-24688-1-git-send-email-palves@redhat.com> <538739A2.2050105@redhat.com> <20141005140039.GA21344@host2.jankratochvil.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20141005140039.GA21344@host2.jankratochvil.net> User-Agent: Mutt/1.5.23 (2014-03-12) X-IsSubscribed: yes X-SW-Source: 2014-10/txt/msg00084.txt.bz2 On Sun, 05 Oct 2014 16:00:39 +0200, Jan Kratochvil wrote: > That message > warning: section not found in /usr/lib/debug/lib/modules/3.16.3-200.fc20.x86_64/vdso/vdso64.so.debug^M > is does not seem to be right - the file looks OK to me - but that seems > unrelated to this regression. Going to check next what vDSO separate debug > info problem it is. The message happens only with the separate debug info installed but in fact the bug can be seen even without the separate debug info installed. kernel-3.16.3-200.fc20.x86_64 (gdb) info files [...] 0x00007ffff7ffb120 - 0x00007ffff7ffb160 is in system-supplied DSO at 0x7ffff7ffb000 ^^ 0x00007ffff7ffb160 - 0x00007ffff7ffb268 is .dynsym in system-supplied DSO at 0x7ffff7ffb000 0x00007ffff7ffb268 - 0x00007ffff7ffb2c6 is .dynstr in system-supplied DSO at 0x7ffff7ffb000 [ 8] .fake_shstrtab STRTAB 0000000000000780 000780 000076 00 A 0 0 32 This is because sh_name==0 for the first section and .fake_shstrtab errorneously did not contain 0x00 as its very first byte (as required by the ELF standard) and therefore BFD considered the first section nameless. I have verified the problem no longer occurs on: kernel-3.17.0-0.rc7.git3.1.fc22.x86_64 (gdb) info files 0x00007ffff7ffd120 - 0x00007ffff7ffd160 is .hash in system-supplied DSO at 0x7ffff7ffd000 ^^^^^ 0x00007ffff7ffd160 - 0x00007ffff7ffd268 is .dynsym in system-supplied DSO at 0x7ffff7ffd000 0x00007ffff7ffd268 - 0x00007ffff7ffd2c6 is .dynstr in system-supplied DSO at 0x7ffff7ffd000 [15] .shstrtab STRTAB 0000000000000000 001308 0000a2 00 0 0 1 Expecting it is probably since: https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=da861e18ecccb5c126b9eb95ff720ce082a46286 x86, vdso: Get rid of the fake section mechanism I have tested that this older kernel also does not have the problem: kernel-3.10.0-123.el7.x86_64 0x00007ffff7ffa120 - 0x00007ffff7ffa160 is .hash in system-supplied DSO at 0x7ffff7ffa000 0x00007ffff7ffa160 - 0x00007ffff7ffa268 is .dynsym in system-supplied DSO at 0x7ffff7ffa000 0x00007ffff7ffa268 - 0x00007ffff7ffa2c6 is .dynstr in system-supplied DSO at 0x7ffff7ffa000 [15] .shstrtab STRTAB 0000000000000000 00105a 0000a3 00 0 0 1 Therefore I do not think it is worth workarounding in GDB. Jan