Re: Core dump on 32-bit Cygwin if program calls dlopen

[Kai Tietz <ktietz70@googlemail.com>]

2014-07-22 15:20 GMT+02:00 Corinna Vinschen wrote:
> On Jul 22 13:59, Jon TURNEY wrote:
>> On 22/07/2014 09:27, Corinna Vinschen wrote:
>> >On Jul 17 20:24, Corinna Vinschen wrote:
>> >>On Jul 17 16:31, Jon TURNEY wrote:
>> >>>On 17/07/2014 08:37, Corinna Vinschen wrote:
>> >>>>It's the libgcc DLL which gives us grief, so a new libgcc package is
>> >>>>sufficent, afaics.  We should check if this DLL fixes the problem and
>> >>>>then make it "curr" soon, I think.
>> >>>
>> >>>I briefly tested this other patch with my test case from the mail above, and
>> >>>it doesn't seem to help.
>> >>>[...]
>> >>I asked DJ to take another look, but I guess ultimately we need the
>> >>attention of one of the GCC Windows maintainers.  Kai Tietz seems to be
>> >>unavailable right now, unfortunately.
>> >
>> >Looks like I totally misunderstood DJ's patch.  The patch does *not*
>> >change libgcc, it changes cygmin-crtbegin.c, thus the crtbegin.o file
>> >which is statically linked into the executable.
>> >
>> >That means, to fix the issue, you don't have to replace libgcc, you
>> >have to recompile the executable against the new crtbegin.o.
>> >
>> >DJ still claims his patch is the correct one.  The simple testcase
>> >dlopen'ing cyggs-9.dll works fine with the new crtbegin.o, according to
>> >him.
>>
>> Sorry, I hadn't tested it correctly.
>
> No worries, this was my fault.  Talking about building a new libgcc
> rather than building a new crtbegin.o was bound to lead everyone
> off track :|
>
>> Building my test with an updated crtbegin.o as well, my test case is fixed.
>
> Nice!
>
>> I agree this patch seems better than my suggested one, as it makes crtbegin
>> do the right thing in the face of unbalanced libgcc load/unload, rather than
>> attempting to balance the libgcc load/unload as mine does.
>
> Ok.  I CC'ed DJ so he knows all is good, and then we probably need a
> windows GCC maintainer to approve the patch I guess.  Kai?  Ping?
>

Hi  Corinna

As I we spoke yesterday on irc, I took already a look to DJ's patch
and it is sensible.  If DJ sends patch upstream to gcc's ML, and put
me CC, I will review it asap.

Thanks,
Kai

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