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bug#46256: [feature/native-comp] AOT eln files ignored if run from build
From: |
Andrea Corallo |
Subject: |
bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree |
Date: |
Mon, 08 Mar 2021 15:02:58 +0000 |
User-agent: |
Gnus/5.13 (Gnus v5.13) Emacs/28.0.50 (gnu/linux) |
Pip Cet <pipcet@gmail.com> writes:
> On Mon, Mar 8, 2021 at 10:14 AM Andrea Corallo <akrl@sdf.org> wrote:
>> Hi Pip,
>>
>> thanks for the analysis, I'm not sure I followed 100% so I'll repeat to
>> make sure we are on the same page, please correct me in case.
>
> Thanks for that!
>
>> IIUC (and make sense to me) the issue is that we are leaving two pointer
>> pointing to the same handle: One is in the CU_2 allocated by
>> 'Fnative_elisp_load' and later discarded by 'load_comp_unit' when
>> reloading the same filename. The other is the original CU_1 created the
>> first time this filename was loaded.
>>
>> When CU_2 will be GC'ed because discarded we'll get the problem because
>> we'll dlclose the handle. Is this correct?
>
> CU_1 is GC'ed first. CU_2, for whatever reason, isn't GC'ed in the same
> cycle.
>
>> In case isn't the attached curing the issue as well?
>
> I don't think so. The problem is that we have an invalid Lisp_Object
> in the shared library, not that we're calling dlclose() too often..
>
> Again, there's no real cost to fixing this: at best, we avoid a
> catastrophic use-after-free. At worst, we nulled out a word of memory
> only for it to be unmapped a moment later, no harm done.
>
>> PS I couldn't reproduce using the lisp reproducer both on my 64bit both
>> on my 32bit system (I left it looping for a while), is that reproducer
>> working for you?
>
> Have you modified dynlib_open() to leak the shared object? That's what
> I think might be happening for Eli, so it makes sense to test with a
> double dlopen() call, as I did.
No, because I failed to understand why calling 'dlopen' two times in a
row on the same filename should make any difference as I expect the
second call to just return the same handle as the first.
I'm sure I'm missing something here or I misunderstood your suggestion:
> I can reproduce this issue by replacing the single call of dlopen() in
> dynlib_open with two calls
Thanks
Andrea
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, (continued)
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Pip Cet, 2021/03/08
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Eli Zaretskii, 2021/03/08
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Pip Cet, 2021/03/08
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Eli Zaretskii, 2021/03/08
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Eli Zaretskii, 2021/03/08
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Eli Zaretskii, 2021/03/07
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Pip Cet, 2021/03/08
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Pip Cet, 2021/03/08
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Andrea Corallo, 2021/03/08
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Pip Cet, 2021/03/08
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree,
Andrea Corallo <=
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Pip Cet, 2021/03/08
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Andrea Corallo, 2021/03/08
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Eli Zaretskii, 2021/03/09
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Andrea Corallo, 2021/03/09
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Eli Zaretskii, 2021/03/09
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Andrea Corallo, 2021/03/09
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Eli Zaretskii, 2021/03/09
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Andrea Corallo, 2021/03/09
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Eli Zaretskii, 2021/03/08
- bug#46256: [feature/native-comp] AOT eln files ignored if run from build tree, Pip Cet, 2021/03/08