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

On Tue, Aug 11, 2015 at 3:57 PM, Sriraman Tallam <> wrote:
> On Tue, Aug 11, 2015 at 3:54 PM, H.J. Lu <> wrote:
>> On Tue, Aug 11, 2015 at 3:37 PM, Paul Pluzhnikov <> wrote:
>>> On Tue, Aug 11, 2015 at 3:31 PM, H.J. Lu <> wrote:
>>>> No.  I am proposing that linker issues an error if there is TEXTREL
>>>> with IFUNC unless "-z now'" is used, assuming that this doesn't
>>>> require changes to nor SELinux.
>>> Ah, ok. But that *doesn't* help current crash at all: "-z now" will
>>> force IFUNC resolver (if any) to be called, and that call will fail
>>> since we are currently removing execute protections.
>>> (This is in fact the situation we've discovered the crash in originally.)
>> Can you try adding  -Wl,-z,execstack?
> Yes, making the stack executable will solve the problem.  My test case
> needed ".note.GNU-stack" specifically for this.

Given SELinux issue, I don't think we should change  Instead,
we can change ld to issue an error for TEXTREL with IFUNC and
suggest -fPIE and  -Wl,-z,execstack as workaround.


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