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Re: Ping x2 Re: [PATCH 1/2][RFC] #17645, fix slow DSO sorting behavior in dynamic loader


On 11/25/19 4:19 AM, Chung-Lin Tang wrote:
> Ping?

Thanks. This is stuck behind one more patch I'm reviewing
for the higher priority (to me) NODELETE rollback fixes.

> On 2019/11/14 5:58 PM, Chung-Lin Tang wrote:
>> On 2019/10/31 9:13 PM, Carlos O'Donell wrote:
>>> On 10/8/19 2:22 AM, Chung-Lin Tang wrote:
>>>> Ping again.
>>>
>>> I have these applied and I'm putting this through testing.
>>
>> Hi Carlos,
>> Thanks for the testing, wonder how it went?
>>
>> Thanks,
>> Chung-Lin
>>
>>>> On 2019/9/17 5:55 PM, Chung-Lin Tang wrote:
>>>>> Ping?
>>>>>
>>>>> On 2019/7/21 1:50 AM, Chung-Lin Tang wrote:
>>>>>> Hi, this patch is our attempt at resolving the slow shared object sorting
>>>>>> situation in #17645, #15310, and some effort at #15311.  I realize this is
>>>>>> pretty unsuitable timing to be submitting a patch of such nature now (probably
>>>>>> way too late to be included into 2.30), but still sending now anyways as this
>>>>>> will probably need quite some discussion before being approved.
>>>>>>
>>>>>> Prior attempts at solving this slow sorting behavior appeared to have failed
>>>>>> due to inadequate proposed testing, therefore cannot convince reviewers to
>>>>>> touch what seems to be perceived as a sensitive and easy to break part of ld.so.
>>>>>>
>>>>>> Therefore the first part of this patch is not a change to the dynamic loader
>>>>>> code proper, but a testing framework for constructing DSO sorting tests.
>>>>>> It consists of a new Python script 'dso-ordering-test.py' that serves to
>>>>>> generate both testcase source files and the needed Makefile fragments from
>>>>>> a short description string, for example:
>>>>>>
>>>>>>       a->b->c->d          // four objects linked one after another
>>>>>>
>>>>>>       a->[bc]->d;b->c     // a depends on b and c, which both depend on d,
>>>>>>                           // b depends on c (b,c linked to object a in fixed order)
>>>>>>
>>>>>>       a->b->c;{+a;%a;-a}  // a, b, c serially dependent, main program uses
>>>>>>                           // dlopen/dlsym/dlclose on object a
>>>>>>
>>>>>>       a->b->c;{}!->[abc]  // a, b, c serially dependent; multiple tests generated
>>>>>>                           // to test all permutations of a, b, c ordering linked
>>>>>>                           // to main program
>>>>>>
>>>>>>      (Above is just a short description of what the script can do, more
>>>>>>       documentation is in the script comments.)
>>>>>>
>>>>>> and, a patch to glibc/elf/Makefile which uses this script to add a few
>>>>>> DSO sorting testcases.  The description string notation and output form of the
>>>>>> generated testcases is short enough that both the test descriptions
>>>>>> and expected outcomes can all directly be specified in the Makefile.
>>>>>>
>>>>>> In terms of the tests I added using this script, I am not completely sure they are
>>>>>> (together with existing tests) adequate to prove algorithmic integrity in face
>>>>>> of any ld.so code changes, but the script should provide a solid tool to further
>>>>>> improve on coverage.  Also welcome suggestions if the current features are still
>>>>>> lacking in expressing some case of shared object relations, or if the documentation
>>>>>> still feels unclear.
>>>>>>
>>>>>> Thanks,
>>>>>> Chung-Lin
>>>>>>
>>>>>> 2019-07-20  Chung-Lin Tang  <cltang@codesourcery.com>
>>>>>>
>>>>>>           [BZ #17645]
>>>>>>           [BZ #15311]
>>>>>>           [BZ #15310]
>>>>>>           * elf/Makefile (test_dso_ordering): New make function.
>>>>>>           (tst-dso-ordering[123456789]): Define new DSO sorting tests.
>>>>>>           (tst-bz15311): Testcase from #15311.
>>>>>>           * scripts/dso-ordering-test.py: New script.
>>>
>>>
> 


-- 
Cheers,
Carlos.


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