From: Chung-Lin Tang <chunglin_tang@mentor.com>
To: GNU C Library <libc-alpha@sourceware.org>
Subject: Ping Re: [PATCH 1/2][RFC] #17645, fix slow DSO sorting behavior in dynamic loader
Date: Tue, 17 Sep 2019 09:55:00 -0000 [thread overview]
Message-ID: <2dea2558-c711-eab5-3728-be4986b7aad5@mentor.com> (raw)
In-Reply-To: <bb13d870-a1f2-94fa-cf9e-9d78ad1fe4ee@mentor.com>
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 // b depends on c (b,c linked to object a in fixed order)
>
> 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 // dlopen/dlsym/dlclose on object a
>
> 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 // 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 // to main program
>
> Â Â (Above is just a short description of what the script can do, more
> 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 [BZ #17645]
> Â Â Â Â Â Â Â [BZ #15311]
> Â Â Â Â Â Â Â [BZ #15310]
> Â Â Â Â Â Â Â * elf/Makefile (test_dso_ordering): New make function.
> Â Â Â Â Â Â Â (tst-dso-ordering[123456789]): Define new DSO sorting tests.
> Â Â Â Â Â Â Â (tst-bz15311): Testcase from #15311.
> Â Â Â Â Â Â Â * scripts/dso-ordering-test.py: New script.
next prev parent reply other threads:[~2019-09-17 9:55 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 ` Chung-Lin Tang [this message]
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
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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