linux-kernel - Re: [PATCH glibc 5/9] glibc: Perform rseq(2) registration at C startup and thread creation (v17)

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Message-ID: <437249723.72685.1588085899422.JavaMail.zimbra@efficios.com>
Date:   Tue, 28 Apr 2020 10:58:19 -0400 (EDT)
From:   Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
To:     Florian Weimer <fw@...eb.enyo.de>
Cc:     Michael Kerrisk <mtk.manpages@...il.com>,
        libc-alpha <libc-alpha@...rceware.org>,
        carlos <carlos@...hat.com>, Rich Felker <dalias@...c.org>,
        linux-api <linux-api@...r.kernel.org>,
        Boqun Feng <boqun.feng@...il.com>,
        Will Deacon <will.deacon@....com>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Peter Zijlstra <peterz@...radead.org>,
        Ben Maurer <bmaurer@...com>, Dave Watson <davejwatson@...com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Paul <paulmck@...ux.vnet.ibm.com>, Paul Turner <pjt@...gle.com>,
        Joseph Myers <joseph@...esourcery.com>,
        Szabolcs Nagy <szabolcs.nagy@....com>
Subject: Re: [PATCH glibc 5/9] glibc: Perform rseq(2) registration at C
 startup and thread creation (v17)

----- On Apr 28, 2020, at 8:54 AM, Florian Weimer fw@...eb.enyo.de wrote:

> * Mathieu Desnoyers:
> 
>> ----- On Apr 28, 2020, at 8:35 AM, Florian Weimer fw@...eb.enyo.de wrote:
>>
>>> * Mathieu Desnoyers:
>>> 
>>>> One issue I'm currently facing when running "make check": because
>>>> nptl/tst-rseq-nptl.c uses pthread_cancel(), I run into an Abort
>>>> with:
>>>>
>>>> libgcc_s.so.1 must be installed for pthread_cancel to work
>>>> Didn't expect signal from child: got `Aborted'
>>> 
>>> This is really unusual.  Is the affected test statically linked?
>>
>> I built glibc without specifying anything particular, and ran
>> "make check". It indeed seems to be dynamically linked to libc:
>>
>> ldd tst-rseq-nptl
>> ./tst-rseq-nptl: /lib/x86_64-linux-gnu/libc.so.6: version `GLIBC_2.32' not found
>> (required by ./tst-rseq-nptl)
>> linux-vdso.so.1 (0x00007ffd3a2f3000)
>> libpthread.so.0 => /lib/x86_64-linux-gnu/libpthread.so.0 (0x00007f0527560000)
>> libc.so.6 => /lib/x86_64-linux-gnu/libc.so.6 (0x00007f052716f000)
>> /home/efficios/glibc-test5/lib/ld-linux-x86-64.so.2 =>
>> /lib64/ld-linux-x86-64.so.2 (0x00007f0527986000)
> 
> That's expected if the installed glibc is older than the built glibc.
> 
>> After make check I have:
>>
>> cat tst-rseq-nptl.test-result
>> FAIL: nptl/tst-rseq-nptl
>> original exit status 134
> 
> What's in the tst-rseq-nptl.out file?

It contains:

Didn't expect signal from child: got `Aborted'

>> And if I run
>>
>> ./tst-rseq-nptl
>>
>> Then I get
>>
>> libgcc_s.so.1 must be installed for pthread_cancel to work
>> Didn't expect signal from child: got `Aborted'
>> libgcc_s.so.1 must be installed for pthread_cancel to work
>> Aborted (core dumped)
> 
> I'm puzzled why you don't get a GLIBC_2.32 version error in this case.
> Do you build with --enable-hardcoded-path-in-tests?

Just tried with this, and it fails the same way. However, the output
of ldd nptl/tst-rseq-nptl changes:

linux-vdso.so.1 (0x00007ffc235c9000)
libpthread.so.0 => /home/efficios/git/glibc-build/nptl/libpthread.so.0 (0x00007fd308278000)
libc.so.6 => /home/efficios/git/glibc-build/libc.so.6 (0x00007fd307ebc000)
/home/efficios/git/glibc-build/elf/ld.so => /lib64/ld-linux-x86-64.so.2 (0x00007fd30869e000)


>> Same result if I do ./testrun.sh nptl/tst-rseq-nptl
> 
> That one definitely should work.
> 
> I expect you might see this if libgcc_s.so.1 is installed into a
> multiarch subdirectory that upstream glibc does not search.  (The
> Debian patches are unfortunately not upstream.)

My test environment is a Ubuntu 18.04.1 LTS.

> 
> I think on my system, the built glibc can find the system libgcc_s via
> /etc/ld.so.cache, so I haven't seen this issue yet.

On my system, libgcc_s is provided here:

/lib/x86_64-linux-gnu/libgcc_s.so.1

by this package:

Package: libgcc1
Architecture: amd64
Version: 1:8.4.0-1ubuntu1~18.04

Thanks,

Mathieu


-- 
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com