From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michal Marek Subject: Re: linux-next: build warnings after merge of the kbuild tree Date: Fri, 19 Aug 2016 10:37:00 +0200 Message-ID: <5babe9ef-0e3d-6975-9ba4-9a29a700b24d@suse.cz> References: <20160817114443.67675413@canb.auug.org.au> <20160818110948.52f1322d@roar.ozlabs.ibm.com> <20160819133854.17a7b1ca@canb.auug.org.au> <20160819150914.36106b5b@canb.auug.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <20160819150914.36106b5b@canb.auug.org.au> Sender: linux-kernel-owner@vger.kernel.org To: Stephen Rothwell , Nicholas Piggin Cc: linux-kernel@vger.kernel.org, linux-next@vger.kernel.org, Al Viro , PowerPC List-Id: linux-next.vger.kernel.org On 2016-08-19 07:09, Stephen Rothwell wrote: > Hi Nick, > > On Fri, 19 Aug 2016 13:38:54 +1000 Stephen Rothwell wrote: >> >> On Thu, 18 Aug 2016 11:09:48 +1000 Nicholas Piggin wrote: >>> >>> On Wed, 17 Aug 2016 14:59:59 +0200 >>> Michal Marek wrote: >>> >>>> On 2016-08-17 03:44, Stephen Rothwell wrote: >>>>> >>>>> After merging the kbuild tree, today's linux-next build (powerpc >>>>> ppc64_defconfig) produced these warnings: >>>>> >>>>> WARNING: 25 bad relocations >>>>> c000000000cf2570 R_PPC64_ADDR64 __crc___arch_hweight16 >>>> [...] >>>>> Introduced by commit >>>>> >>>>> 9445aa1a3062 ("ppc: move exports to definitions") >>>>> >>>>> I have reverted that commit for today. >>>>> >>>>> [cc-ing the ppc guys for clues - also involved is commit >>>>> >>>>> 22823ab419d8 ("EXPORT_SYMBOL() for asm") >>>>> ] >>>> >>>> FWIW, I see these warnings as well. Any help from ppc developers is >>>> appreciated - should the R_PPC64_ADDR64 be whitelisted for exported asm >>>> symbols (their CRCs actually)? >>> >>> The dangling relocation is a side effect of linker unable to resolve the >>> reference to the undefined weak symbols. So the real question is, why has >>> genksyms not overridden these symbols with their CRC values? >>> >>> This may not even be powerpc specific, but I'll poke at it a bit more >>> when I get a chance. >> >> Not sure if this is relevant, but with the commit reverted, the >> __crc___... symbols are absolute. >> >> 00000000f55b3b3d A __crc___arch_hweight16 > > Ignore that :-) > > I just had a look at a x86_64 allmodconfig result and it looks like the > weak symbols are not resolved their either ... > > I may be missing something, but genksyms generates the crc's off the > preprocessed C source code and we don't have any for the asm files ... Of course you are right. Which means that we are losing type information for these exports for CONFIG_MODVERSIONS purposes. I guess it's acceptable, since the asm functions are pretty basic and their signatures do not change. Michal