[Buildroot] [PATCH 2/2] package/lvm2: Fix runtime crash when using uclibc

[Thomas Petazzoni <thomas.petazzoni@bootlin.com>]

Hello Marcin,

On Wed, 25 Jul 2018 14:37:03 +0200, Marcin Niestroj wrote:
> When using uclibc libdevmapper.so was calling dm_task_get_info_base()
> function recursively, leading to segmentation fault. This was
> happening because uclibc linker loader just takes first existing
> 'dm_task_get_info' (which is 'dm_task_get_info_base') symbol in elf
> binary, instead of default version.
> 
> Add upstreamable lvm2 patch [1], which introduces
> --enable-symvers[=STYLE] switch. Use that switch to disable symbol
> versions, as we do not plan to support binaries compiled against
> old libdevmapper library.
> 
> [1] https://www.redhat.com/archives/dm-devel/2018-July/msg00187.html
> 
> Signed-off-by: Marcin Niestroj <m.niestroj@grinn-global.com>

Is this needed only with the lvm2 bump to 2.02.180 ? Or is it needed
even with the current version of lvm2 we have packaged in Buildroot ?

> ---
>  ...gure-Introduce-enable-symvers-option.patch | 288 ++++++++++++++++++
>  package/lvm2/lvm2.mk                          |   3 +-
>  2 files changed, 290 insertions(+), 1 deletion(-)
>  create mode 100644 package/lvm2/0001-configure-Introduce-enable-symvers-option.patch
> 
> diff --git a/package/lvm2/0001-configure-Introduce-enable-symvers-option.patch b/package/lvm2/0001-configure-Introduce-enable-symvers-option.patch
> new file mode 100644
> index 0000000000..757305a86d
> --- /dev/null
> +++ b/package/lvm2/0001-configure-Introduce-enable-symvers-option.patch
> @@ -0,0 +1,288 @@
> +From f4fb05978de506c6941c80493c4f3b77f0509913 Mon Sep 17 00:00:00 2001
> +From: Marcin Niestroj <m.niestroj@grinn-global.com>
> +Date: Fri, 20 Jul 2018 14:26:44 +0200
> +Subject: [PATCH] configure: Introduce --enable-symvers option
> +
> +Only few libc (e.g. glibc) libraries support full symbol version
> +resolution in runtime. There are lot of standard libraries that do not
> +support that, such as dietlibc, musl and uclibc. Hence there is no
> +reason to generate symbol versions when compiling against them.
> +
> +Additionally libdevmapper.so was broken when compiled against
> +uclibc. Runtime linker loader caused calling dm_task_get_info_base()
> +function recursively, leading to segmentation fault.
> +
> +Introduce --enable-symvers[=STYLE] option, which allows to choose
> +between gnu and disabled symbol versioning. By default gnu symbol
> +versioning is used to provide backward compatibility.
> +__GNUC__ check is replaced now with GNU_SYMVER, which is generated by
> +configure script. Additionally ld version script is included only in
> +case of gnu option, which slightly reduces output size.
> +
> +Providing --disable-symvers to configure script when building against
> +uclibc library fixes segmentation fault error described above, due to
> +lack of several versions of the same symbol in libdevmapper.so
> +library.

Could you add your SoB to the patch itself ?

Thanks!

Thomas
-- 
Thomas Petazzoni, CTO, Bootlin (formerly Free Electrons)
Embedded Linux and Kernel engineering
https://bootlin.com