From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: multipart/mixed; boundary="===============3543319257067826142==" MIME-Version: 1.0 From: Jan Kratochvil To: elfutils-devel@lists.fedorahosted.org Subject: Re: [PATCH] Add --core-pattern option to eu-stack Date: Thu, 27 Nov 2014 22:27:11 +0100 Message-ID: <20141127212711.GA29375@host2.jankratochvil.net> In-Reply-To: 1417086279.4954.37.camel@bordewijk.wildebeest.org --===============3543319257067826142== Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable On Thu, 27 Nov 2014 12:04:39 +0100, Mark Wielaard wrote: > On Wed, 2014-11-26 at 15:32 +0100, Jan Kratochvil wrote: > > Therefore they are dead at the core_pattern time, they cannot be ptrace= d and > > therefore they cannot be unwound. One could only find them in the core = file > > itself but that is outside of the scope of this eu-stack feature. > = > Why do you think that is out of scope? We get both the actual tid > through the command line option and the core file through stdin. Can't > we combine those two to get all information we want/need? It could be extended that way but: Currently elfutils is used only for the list of unwound PCs. There is miss= ing a big part of functionality present in GDB - displaying parameters, local variables, entry-value recovered values, data types pretty printing etc. And I have doubts unwind of non-crashed threads is useful at all. It is a new functionality on top of this patch that it has to read thread registers from PT_NOTE but access the memory via ptraced crashed thread. Fortunately core file PT_NOTE is first so it can be read quickly: Program Headers: Type Offset VirtAddr PhysAddr FileSiz Me= mSiz Flg Align NOTE 0x0004a0 0x0000000000000000 0x0000000000000000 0x0005f4 0x= 000000 0 As reading the whole core file is in many times not possible (without some better kernel core dumping interface): -fsanitize=3Daddress locks up abrt-hook-ccpp https://bugzilla.redhat.com/show_bug.cgi?id=3D1164548 So I agree your proposal makes some sense but: * I find it an incremental feature on top of this one. * Given elfutils just lists the unwound PCs I do not see how it is useful. What is your - or Martin's - opinion on such feature given these contraints? Thanks, Jan --===============3543319257067826142==--