Bug#943798: ld.so: old Arm ABI detection patch causing problems, time to remove?
On 2019-10-30 00:17, Steve McIntyre wrote:
> Source: glibc
> Version: 2.28-10
> Severity: important
>
> Hi folks,
>
> It looks like my old Arm ABI detection patch for ld.so is causing
> problems for people using LLVM. I've been contacted by a developer,
> referring to a mailing list thread:
>
> https://lists.llvm.org/pipermail/llvm-dev/2019-October/135993.html
>
> It looks like the LLVM version of strip is more aggressive than the
> GNU binutils version, and this is causing problems - it's stripping
> the .ARM.attributes data and that's causing problems with our extra
> checks for the Tag_ABI_VFP_args setting. Whether that's a valid thing
> to do or not is an argument for another day, I think... However,
> checking with the bzip2 binaries that the reporter provided I can see
> that they have the right ABI flag in the ELF header but we're still
> running the extra ABI check:
>
> (sid-armhf)steve@mjolnir:~/abi$ LD_PRELOAD=./libbz2.so.all ./bzip2
> ERROR: ld.so: object './libbz2.so.all' from LD_PRELOAD cannot be preloaded (cannot open shared object file): ignored.
> bzip2: I won't write compressed data to a terminal.
> bzip2: For help, type: `bzip2 --help'.
>
> (sid-armhf)steve@mjolnir:~/abi$ readelf -a libbz2.so.all | grep "^ Flags"
> Flags: 0x5000400, Version5 EABI, hard-float ABI
>
> I think this is wrong, and I can't think of why I didn't find this
> earlier when I was working in this area. :-/
>
> So: I think we have two sensible options:
>
> 1. I find time now to fix up ld.so to only do the extra check here if
> we think it's needed
>
> OR
>
> 2. Just remove the patch for extra check here - it was always the plan
> that this would go away after a while once people were unlikely to
> still be running binaries from the pre ELF-header toolchains.
>
> Checking history, I can see that the binutils changes for those ELF
> header changes landed in Debian back in Nov 2012. (Wow, time
> flies!). Given that, I'd now be strongly in favour of just dropping the
> patch in
>
> debian/patches/arm/unsubmitted-ldso-abi-check.diff
>
> as it's now safely obsolete. What do others think?
Given this patch is not needed anymore, I also thing it's the way to do.
It caused us issue in the past, so i'll be very happy to see it going
away.
--
Aurelien Jarno GPG: 4096R/1DDD8C9B
aurelien@aurel32.net http://www.aurel32.net
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