From mboxrd@z Thu Jan 1 00:00:00 1970 X-Msuck: nntp://news.gmane.org/gmane.linux.lib.musl.general/15114 Path: news.gmane.org!.POSTED.blaine.gmane.org!not-for-mail From: Szabolcs Nagy Newsgroups: gmane.linux.lib.musl.general Subject: Re: another armv7-m exception handling problem Date: Fri, 10 Jan 2020 11:22:14 +0100 Message-ID: <20200110102214.GR23985@port70.net> References: <20191021180956.GQ7832@port70.net> <20191021190318.GI16318@brightrain.aerifal.cx> <20191021190857.GR7832@port70.net> <20191021192937.GJ16318@brightrain.aerifal.cx> Reply-To: musl@lists.openwall.com Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Injection-Info: blaine.gmane.org; posting-host="blaine.gmane.org:195.159.176.226"; logging-data="108237"; mail-complaints-to="usenet@blaine.gmane.org" User-Agent: Mutt/1.10.1 (2018-07-13) Cc: Patrick Oppenlander To: musl@lists.openwall.com Original-X-From: musl-return-15130-gllmg-musl=m.gmane-mx.org@lists.openwall.com Fri Jan 10 11:23:48 2020 Return-path: Envelope-to: gllmg-musl@m.gmane-mx.org Original-Received: from mother.openwall.net ([195.42.179.200]) by blaine.gmane.org with smtp (Exim 4.89) (envelope-from ) id 1iprR2-0009vI-7U for gllmg-musl@m.gmane-mx.org; Fri, 10 Jan 2020 11:22:32 +0100 Original-Received: (qmail 22028 invoked by uid 550); 10 Jan 2020 10:22:27 -0000 Mailing-List: contact musl-help@lists.openwall.com; run by ezmlm Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-ID: Original-Received: (qmail 22007 invoked from network); 10 Jan 2020 10:22:27 -0000 Mail-Followup-To: musl@lists.openwall.com, Patrick Oppenlander Content-Disposition: inline In-Reply-To: <20191021192937.GJ16318@brightrain.aerifal.cx> Xref: news.gmane.org gmane.linux.lib.musl.general:15114 Archived-At: * Rich Felker [2019-10-21 15:29:37 -0400]: > On Mon, Oct 21, 2019 at 09:08:57PM +0200, Szabolcs Nagy wrote: > > * Rich Felker [2019-10-21 15:03:18 -0400]: > > > On Mon, Oct 21, 2019 at 08:09:56PM +0200, Szabolcs Nagy wrote: > > > > * Patrick Oppenlander [2019-10-21 15:43:40 +1100]: > > > > > Not sure if this is a musl, gcc or ld bug. > > > > > > > > > > Running gcc-8.3.0 musl 1.1.24 static pie. > > > > > > > > providing binutils version number is useful if there is > > > > a chance that it's an ld bug. > > > > > > > > this seems to be > > > > https://sourceware.org/bugzilla/show_bug.cgi?id=22269 > > > > > > > > which was supposed to be fixed by > > > > https://sourceware.org/git/gitweb.cgi?p=binutils-gdb.git;h=95b03e4ad68e7a90f5096b47df595636344b783a > > > > > > > > but apperently there are still missing cases. > > > > (it does not help that the ld test for this bug > > > > greps for R_*_NONE dynrelocs but not R_*_RELATIVE > > > > which i is just as bad for undef weak syms in pie) > > > > i added a note to the bug. > > > > > > > > if you add __attribute__((visibility("hidden"))) > > > > to the example given by Rich then it works, the > > > > bug only affects static pie linking. > > > > > > That's really weird. How does it end up having an outstanding > > > *relative* relocation when it's not defined locally? I could > > > understand having a bogus outstanding symbolic one, but relative makes > > > no sense and suggests ld is doing something very wrong... > > > > i'd guess it creates a relative reloc for every > > got entry that stores some symbol's address > > which is known to be local, which makes sense, > > except for undefined weak symbols which should > > have fixed 0 address. > > > > and i'd guess there is some logic that special > > cases local undef weak in pic so hidden works, > > and that check should be extended to cover the > > static pie case. > > In 2.33.1, the offending code (creating the bad relative relocation) > is at line 11637. It's possible some earlier code path leading to it > is wrong, around line 11515 or so, but I think there just needs to be > an extra else path before this one that covers undefined/undefweak. fyi i have a patch now, hopefully will be included into binutils 2.34 https://sourceware.org/ml/binutils/2020-01/msg00096.html