From: Chung-Lin Tang <chunglin_tang@mentor.com>
To: Carlos O'Donell <carlos@redhat.com>, <cltang@codesourcery.com>,
GNU C Library <libc-alpha@sourceware.org>
Subject: Re: Ping x2 Re: [PATCH 1/2][RFC] #17645, fix slow DSO sorting behavior in dynamic loader
Date: Thu, 14 Nov 2019 09:58:00 -0000 [thread overview]
Message-ID: <65a2cd71-8ad5-9122-a8cc-a54e8fbe89b5@mentor.com> (raw)
In-Reply-To: <55008c83-b935-c1b0-1166-2df97d1715b6@redhat.com>
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,
>>>> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â // b depends on c (b,c linked to object a in fixed order)
>>>>
>>>> Â Â Â Â a->b->c;{+a;%a;-a}Â // a, b, c serially dependent, main program uses
>>>> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â // dlopen/dlsym/dlclose on object a
>>>>
>>>> Â Â Â Â a->b->c;{}!->[abc]Â // a, b, c serially dependent; multiple tests generated
>>>> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â // to test all permutations of a, b, c ordering linked
>>>> Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â Â // to main program
>>>>
>>>> Â Â Â (Above is just a short description of what the script can do, more
>>>> Â Â Â Â 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>
>>>>
>>>> Â Â Â Â Â Â Â Â [BZ #17645]
>>>> Â Â Â Â Â Â Â Â [BZ #15311]
>>>> Â Â Â Â Â Â Â Â [BZ #15310]
>>>> Â Â Â Â Â Â Â Â * elf/Makefile (test_dso_ordering): New make function.
>>>> Â Â Â Â Â Â Â Â (tst-dso-ordering[123456789]): Define new DSO sorting tests.
>>>> Â Â Â Â Â Â Â Â (tst-bz15311): Testcase from #15311.
>>>> Â Â Â Â Â Â Â Â * scripts/dso-ordering-test.py: New script.
>
>
next prev parent reply other threads:[~2019-11-14 9:58 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-07-20 17:51 Chung-Lin Tang
2019-07-23 13:21 ` Florian Weimer
2019-07-25 18:46 ` Chung-Lin Tang
2019-07-29 9:48 ` Florian Weimer
2019-08-05 10:39 ` Chung-Lin Tang
2019-08-05 10:45 ` Florian Weimer
2019-08-10 11:49 ` Chung-Lin Tang
2019-09-17 9:55 ` Ping " Chung-Lin Tang
2019-10-08 6:22 ` Ping x2 " Chung-Lin Tang
2019-10-08 17:41 ` Adhemerval Zanella
2019-10-31 13:13 ` Carlos O'Donell
2019-11-14 9:58 ` Chung-Lin Tang [this message]
2019-11-25 9:19 ` Chung-Lin Tang
2019-11-25 19:08 ` Carlos O'Donell
2019-11-26 8:19 ` Chung-Lin Tang
2019-11-27 15:20 ` Carlos O'Donell
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