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Re: [PATCH 1/5] glibc: Perform rseq(2) registration at C startup and thread creation (v10)
- From: Mathieu Desnoyers <mathieu dot desnoyers at efficios dot com>
- To: Florian Weimer <fweimer at redhat dot com>
- Cc: carlos <carlos at redhat dot com>, Joseph Myers <joseph at codesourcery dot com>, Szabolcs Nagy <szabolcs dot nagy at arm dot com>, libc-alpha <libc-alpha at sourceware dot org>, Thomas Gleixner <tglx at linutronix dot de>, Ben Maurer <bmaurer at fb dot com>, Peter Zijlstra <peterz at infradead dot org>, "Paul E. McKenney" <paulmck at linux dot vnet dot ibm dot com>, Boqun Feng <boqun dot feng at gmail dot com>, Will Deacon <will dot deacon at arm dot com>, Dave Watson <davejwatson at fb dot com>, Paul Turner <pjt at google dot com>, Rich Felker <dalias at libc dot org>, linux-kernel <linux-kernel at vger dot kernel dot org>, linux-api <linux-api at vger dot kernel dot org>
- Date: Fri, 14 Jun 2019 08:55:10 -0400 (EDT)
- Subject: Re: [PATCH 1/5] glibc: Perform rseq(2) registration at C startup and thread creation (v10)
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----- On Jun 14, 2019, at 1:35 PM, Florian Weimer fweimer@redhat.com wrote:
> * Mathieu Desnoyers:
>
>> * Makefile:
>>
>> LIBCPATH=/home/efficios/glibc-test/lib
>> KERNEL_HEADERS=/home/efficios/git/linux-percpu-dev/usr/include
>> CFLAGS=-I${KERNEL_HEADERS} -L${LIBCPATH} -Wl,--rpath=${LIBCPATH}
>> -Wl,--dynamic-linker=${LIBCPATH}/ld-linux-x86-64.so.2
>>
>> all:
>> gcc ${CFLAGS} -o a a.c
>> gcc ${CFLAGS} -shared -fPIC -o s.so s.c
>
> For me, that does not correctly link against the built libc because the
> system dynamic loader seeps into the link.
I have the same issue. I tried adding "-B${LIBCPATH}" as well, but it did
not seem to help. I still have this ldd output:
ldd a
./a: /lib64/ld-linux-x86-64.so.2: version `GLIBC_2.30' not found (required by ./a)
linux-vdso.so.1 (0x00007fffaa7e9000)
libc.so.6 => /home/efficios/glibc-test/lib/libc.so.6 (0x00007fac5d479000)
/home/efficios/glibc-test/lib/ld-linux-x86-64.so.2 => /lib64/ld-linux-x86-64.so.2 (0x00007fac5da33000)
Still no luck there. Any idea what compiler/linker flag I am missing ?
>
>> specifically this commit:
>> https://github.com/compudj/glibc-dev/commit/c49a286497d065a7fc00aafd846e6edce14f97fc
>
> This commit links __rseq_handled into libc.so.6 via rseq-sym.c, but does
> not export it from there.
Moving __rseq_handled to elf/dl-support.c and elf/rtld.c was part a commit on top.
I've force-pushed on the dev branch, and the commit moving __rseq_handled to the
dynamic linker it now appears as:
https://github.com/compudj/glibc-dev/commit/f0d4e60e5d0ceb0c2642f99da5af61b6ad988531
Thanks,
Mathieu
--
Mathieu Desnoyers
EfficiOS Inc.
http://www.efficios.com