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 for kexec@lists.infradead.org; Wed, 15 Dec 2021 17:48:29 +0000
Date: Wed, 15 Dec 2021 18:48:17 +0100
From: Heiko Carstens <hca@linux.ibm.com>
Subject: Re: [PATCH 1/1] s390: handle R_390_PLT32DBL reloc entries in
 machine_apply_elf_rel()
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References: <20211208125355.256391-1-egorenar@linux.ibm.com>
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To: Simon Horman <horms@verge.net.au>
Cc: Philipp Rudo <prudo@redhat.com>, Alexander Egorenkov <egorenar@linux.ibm.com>, ltao@redhat.com, kexec@lists.infradead.org

On Wed, Dec 15, 2021 at 01:43:00PM +0100, Simon Horman wrote:
> On Mon, Dec 13, 2021 at 11:44:30AM +0100, Philipp Rudo wrote:
> > Hi Alexander,
> > 
> > @Alexander: Thanks for taking care of this.
> > 
> > On Wed,  8 Dec 2021 13:53:55 +0100
> > Alexander Egorenkov <egorenar@linux.ibm.com> wrote:
> > 
> > > Starting with gcc 11.3, the C compiler will generate PLT-relative function
> > > calls even if they are local and do not require it. Later on during linking,
> > > the linker will replace all PLT-relative calls to local functions with
> > > PC-relative ones. Unfortunately, the purgatory code of kexec/kdump is
> > > not being linked as a regular executable or shared library would have been,
> > > and therefore, all PLT-relative addresses remain in the generated purgatory
> > > object code unresolved. This leads to the situation where the purgatory
> > > code is being executed during kdump with all PLT-relative addresses
> > > unresolved. And this results in endless loops within the purgatory code.
> > 
> > Tiny nit. The last two sentences describe the situation in the kernel.
> > Luckily the kexec-tools do proper error checking and die with
> > 
> > 	"Unknown rela relocation: 0x14 0x73c0901c"
> > 
> > when they encounter an unknown relocation type.
> > 
> > Anyway, the code is correct
> > 
> > Reviewed-by: Philipp Rudo <prudo@redhat.com>
> 
> Thanks.
> 
> Alexander would you care to post a v2 with an updated patch description?

Given that Alexander is currently not available, I will resend his
patch with an updated commit message.

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