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Re: [PATCH] [PR libc/18801] PIE binary with STT_GNU_IFUNC symbol and TEXTREL segfaults on x86_64

From: Mike Frysinger <vapier at gentoo dot org>
To: Paul Pluzhnikov <ppluzhnikov at google dot com>
Cc: "H.J. Lu" <hjl dot tools at gmail dot com>, Sriraman Tallam <tmsriram at google dot com>, GLIBC Devel <libc-alpha at sourceware dot org>, Ian Lance Taylor <iant at google dot com>, David Li <davidxl at google dot com>
Date: Wed, 12 Aug 2015 03:10:25 -0400
Subject: Re: [PATCH] [PR libc/18801] PIE binary with STT_GNU_IFUNC symbol and TEXTREL segfaults on x86_64
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On 11 Aug 2015 23:15, Paul Pluzhnikov wrote:
> On Tue, Aug 11, 2015 at 10:48 PM, Mike Frysinger wrote:
> > i don't see why we should make any change.  it isn't ld's problem that the
> > restrictive runtime prevents things.  ld already issues a warning when you
> > have textrels in shared segments, so let's leave it at that.
> 
> For the test case, ld does not issue any warnings:
> 
> gcc -fPIE -pie tst-pie-ifunc-txtrel.S
> readelf -d a.out | grep TEXTREL
>  0x0000000000000016 (TEXTREL)            0x0
> 
> Apparently --warn-shared-textrel is not the default for GNU ld (GNU
> Binutils for Ubuntu) 2.24.

it is in Gentoo ;).  i wouldn't mind that going upstream.

> The resulting binary crashes inside ld.so, for no apparent reason:

i'm ambivalent on the ld.so change.  the quoted context i used before
was just for the ld part, not ld.so.
-mike

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References:
- Re: [PATCH] [PR libc/18801] PIE binary with STT_GNU_IFUNC symbol and TEXTREL segfaults on x86_64
  - From: Paul Pluzhnikov
- Re: [PATCH] [PR libc/18801] PIE binary with STT_GNU_IFUNC symbol and TEXTREL segfaults on x86_64
  - From: H.J. Lu
- Re: [PATCH] [PR libc/18801] PIE binary with STT_GNU_IFUNC symbol and TEXTREL segfaults on x86_64
  - From: Paul Pluzhnikov
- Re: [PATCH] [PR libc/18801] PIE binary with STT_GNU_IFUNC symbol and TEXTREL segfaults on x86_64
  - From: H.J. Lu
- Re: [PATCH] [PR libc/18801] PIE binary with STT_GNU_IFUNC symbol and TEXTREL segfaults on x86_64
  - From: Paul Pluzhnikov
- Re: [PATCH] [PR libc/18801] PIE binary with STT_GNU_IFUNC symbol and TEXTREL segfaults on x86_64
  - From: H.J. Lu
- Re: [PATCH] [PR libc/18801] PIE binary with STT_GNU_IFUNC symbol and TEXTREL segfaults on x86_64
  - From: Sriraman Tallam
- Re: [PATCH] [PR libc/18801] PIE binary with STT_GNU_IFUNC symbol and TEXTREL segfaults on x86_64
  - From: H.J. Lu
- Re: [PATCH] [PR libc/18801] PIE binary with STT_GNU_IFUNC symbol and TEXTREL segfaults on x86_64
  - From: Mike Frysinger
- Re: [PATCH] [PR libc/18801] PIE binary with STT_GNU_IFUNC symbol and TEXTREL segfaults on x86_64
  - From: Paul Pluzhnikov

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