Erik Bray wrote:
> On Sat, Jul 30, 2016 at 8:25 PM, leif <not.rea...@online.de> wrote:
>> leif wrote:
>>> Erik Bray wrote:
>>>> On Thu, Jul 28, 2016 at 8:03 PM, Erik Bray <erik.m.b...@gmail.com> wrote:
>>>>> On Thu, Jul 28, 2016 at 4:32 PM, Erik Bray <erik.m.b...@gmail.com> wrote:
>>>>>> ...and in particular, are any omalloc experts watching this list?
>>>>>>
>>>>>> I ask because my current issue in the Cygwin port of Sage is a
>>>>>> segfault that's occurring in Singular during a routine memory
>>>>>> deallocation of GMP integers.
>>>>>>
>>>>>> I'm working on getting a Singular compiled without omalloc to see if
>>>>>> that makes any difference. In the meantime I just thought I'd reach
>>>>>> out to see what expertise I have to draw on in the community.
>>>>>
>>>>> Thanks everyone for all the tips. I'm heading out for vacation again
>>>>> but will be back in a week and will go through them one by one.
>>>>>
>>>>> For what it's worth I think I'm close in on the problem:
>>>>>
>>>>> The way Singular is being built and/or how DLLs are being loaded it's
>>>>> ending up with both GMP and MPIR simultaneously, and this causes a
>>>>> great deal of confusion, not the least of which that
>>>>> mp_set_memory_functions is being called in one but not the other.
>>>>>
>>>>> The end result is a segfault on a memory address that was allocated
>>>>> with the system allocator, but is being freed by omalloc.
>>>>>
>>>>> Not sure why this is happening but it must be a build issue.
>>>>
>>>> I just completed a build of Singular where I had forcibly changed all
>>>> instances of -lgmp to -lmpir in the makefiles, and it works now, so
>>>> that's reassuring.
>>>
>>> When you're back, you could try building Sage with the optional GMP
>>> package*. I'm curious as to whether you'll then get two instances of
>>> GMP... ;-)
>>>
>>> (The optional package is still at 5.1.3 IIRC though, but until then I'll
>>> perhaps have upgraded it to GMP 6.1.1.)
>>
>> Just be warned: Building Sage with its GMP package appears to be broken.
>>
>> First of all, it's not sufficient to reconfigure with --with-mp=gmp and
>> rerun 'make' (which was, AFAIK, supposed to or intended to work).
>>
>> Running 'make build-clean' and then reconfiguring doesn't work either;
>> presumably that doesn't rebuild everything that it should. (Gave
>> hundreds of crashes and timeouts in ptestlong IIRC, among them glibc
>> detected invalid free()s and realloc()s of python.)
>>
>> Deleting local/var/lib/sage/installed/* in advance "worked", but gave
>> trouble in the build (e.g. gf2x's tuning consistently failed with an
>> assertion error). With GCC 6.1. at least, the build finally succeeded
>> (is installing sagetex-3.0 with SAGE_CHECK=yes supposed to work?), but
>> docbuilding got stuck, leaving 1 to N (-jN) python processes, 1 or N-1
>> running 100% without any progress even after hours. (I also retried a
>> couple of times.)
>>
>> On a similar system, I did build Sage 7.3.rc0 with SAGE_INSTALL_GCC=yes
>> and --with-mp=gmp from scratch, which led to a couple of doctest errors,
>> most of them "harmless" I think, but also crashes in e.g. libsingular.
>
> To be honest I'm not even sure how I ended up with GMP in my Sage
> install in the first place. I never did --with-mp=gmp. Or is that
> what the --enable-gmpcompat flag to MPIR's configure does? Regardless
> the end result is two complete copies of the library (I would have
> thought just a symlink from mpir to gmp or something).
>
> Singular links explicitly against "gmp", while many other packages are
> linked to "mpir". In the end both are being loaded and some symbols
> being resolved to one, while other symbols resolved to the other.
> It's very confusing.
We removed any explicit mention of MPIR ('-lmpir', '#include <mpir.h>')
a while ago, but a few newer packages may indeed recognize MPIR
meanwhile and link to that instead. But I'm not aware of a single one.
-leif
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