From: "H.J. Lu" <hjl.tools@gmail.com>
To: Adhemerval Zanella Netto <adhemerval.zanella@linaro.org>
Cc: libc-alpha@sourceware.org
Subject: Re: [PATCH] Make clone3 shared-only [BZ #31770]
Date: Tue, 21 May 2024 05:55:57 -0700 [thread overview]
Message-ID: <CAMe9rOqudu=TdHtv2E50c-fawVj8r5BWAi2QYFb-iwU1zZ+wpA@mail.gmail.com> (raw)
In-Reply-To: <7bf33c04-aca0-4f26-bcdd-3b23b901aaa6@linaro.org>
On Tue, May 21, 2024 at 5:50 AM Adhemerval Zanella Netto
<adhemerval.zanella@linaro.org> wrote:
>
>
>
> On 20/05/24 23:31, H.J. Lu wrote:
> > clone3 isn't exported from libc.so. Fix BZ #31770 by making clone3
> > shared-only.
> >
> > Signed-off-by: H.J. Lu <hjl.tools@gmail.com>
> > ---
> > sysdeps/unix/sysv/linux/Makefile | 1 +
> > 1 file changed, 1 insertion(+)
> >
> > diff --git a/sysdeps/unix/sysv/linux/Makefile b/sysdeps/unix/sysv/linux/Makefile
> > index 415aa1f14d..233db08be7 100644
> > --- a/sysdeps/unix/sysv/linux/Makefile
> > +++ b/sysdeps/unix/sysv/linux/Makefile
> > @@ -112,6 +112,7 @@ sysdep_routines += \
> > xstat \
> > xstat64 \
> > # sysdep_routines
> > +shared-only-routines += clone3
> >
> > CFLAGS-gethostid.c = -fexceptions
> > CFLAGS-tee.c = -fexceptions -fasynchronous-unwind-tables
>
> We need __clone3 for posix_spawn and pthread_create, so making it shared-only
> is not correct. Wit this patch applied:
>
> $ make test t=posix/tst-spawn-static run-built-tests=no
> x86_64-glibc-linux-gnu-gcc -o /home/azanella/Projects/glibc/build/x86_64-linux-gnu/posix/tst-spawn-static -nostdlib -nostartfiles -static -static-pie [...]
> /home/azanella/toolchain/install/compilers/14/x86_64-linux-gnu/bin/../lib/gcc/x86_64-glibc-linux-gnu/14.1.1/../../../../x86_64-glibc-linux-gnu/bin/ld: /home/azanella/Projects/glibc/build/x86_64-linux-gnu/libc.a(spawni.o): in function `__spawnix':
> /home/azanella/Projects/glibc/glibc-git/posix/../sysdeps/unix/sysv/linux/spawni.c:417:(.text+0x231): undefined reference to `__clone3'
> /home/azanella/toolchain/install/compilers/14/x86_64-linux-gnu/bin/../lib/gcc/x86_64-glibc-linux-gnu/14.1.1/../../../../x86_64-glibc-linux-gnu/bin/ld: /home/azanella/Projects/glibc/build/x86_64-linux-gnu/libc.a(clone-internal.o): in function `__clone3_internal':
> [...]
>
> The correct approach is to remove the __clone3 to clone3 alias in
> *all* clone3.S implementations:
Can you review
https://patchwork.sourceware.org/project/glibc/list/?series=34172
Thanks.
> diff --git a/sysdeps/unix/sysv/linux/x86_64/clone3.S b/sysdeps/unix/sysv/linux/x86_64/clone3.S
> index 5a2d42234e..4cc19e066c 100644
> --- a/sysdeps/unix/sysv/linux/x86_64/clone3.S
> +++ b/sysdeps/unix/sysv/linux/x86_64/clone3.S
> @@ -86,4 +86,3 @@ L(thread_start):
> PSEUDO_END (__clone3)
>
> libc_hidden_def (__clone3)
> -weak_alias (__clone3, clone3)
>
> Which results in:
>
> x86_64-linux-gnu$ readelf -sW libc.a | grep clone3
> 19: 0000000000000000 0 NOTYPE GLOBAL HIDDEN UND __clone3
> 4: 0000000000000000 4 OBJECT LOCAL DEFAULT 3 clone3_supported.0
> 15: 0000000000000060 137 FUNC GLOBAL HIDDEN 1 __clone3_internal
> 16: 0000000000000000 0 NOTYPE GLOBAL HIDDEN UND __clone3
> File: libc.a(clone3.o)
> 7: 0000000000000000 71 FUNC GLOBAL DEFAULT 1 __clone3
--
H.J.
prev parent reply other threads:[~2024-05-21 12:56 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-05-21 2:31 H.J. Lu
2024-05-21 12:50 ` Adhemerval Zanella Netto
2024-05-21 12:55 ` H.J. Lu [this message]
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