[PATCH] perf s390: Fix TEXTREL in Python extension by compiling as PIC

[PATCH] perf s390: Fix TEXTREL in Python extension by compiling as PIC

[Jens Remus]

On s390 the Python extension build fails as follows when using a linker
that is configured to treat text relocations (TEXTREL) in shared
libraries as error by default:

  GEN     python/perf.cpython-314-s390x-linux-gnu.so
/usr/bin/ld.bfd: error: read-only segment has dynamic relocations

This occurrs because util/llvm-c-helpers.o is erroneously built from
util/llvm-c-helpers.cpp without compiler option -fPIC but linked into
the shared library (via libperf-util.a(perf-util-in.o)).

On s390, object files must be compiled as position-indepedent code (PIC)
in order to be linked into shared libraries.  Commit a9a3f1d18a6c ("perf
s390: Always build with -fPIC") added compiler option -fPIC to CFLAGS
for s390, which is used in C compiles.  Add -fPIC to CXXFLAGS for s390
as well, so that it is also used in C++ compiles.

Reported-by: Thomas Richter <tmricht@linux.ibm.com>
Signed-off-by: Jens Remus <jremus@linux.ibm.com>
---

Notes (jremus):
    This patch applies on top of the perf-tools-next tree:
    
      git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git  master
    
    Note that this resolves the issue discussed in thread "[PATCH 1/1] perf
    build: Fix Python extension build with GCC 16 hardening":
    https://lore.kernel.org/all/ahV2XGx_6h7upuc3@li-276bd24c-2dcc-11b2-a85c-945b6f05615c.ibm.com/T/

 tools/perf/Makefile.config | 1 +
 1 file changed, 1 insertion(+)

diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 333ddd0e4bd8..33f90968c8a9 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -109,6 +109,7 @@ endif
 
 ifeq ($(ARCH),s390)
   CFLAGS += -fPIC
+  CXXFLAGS += -fPIC
 endif
 
 ifeq ($(ARCH),mips)
-- 
2.53.0

Re: [PATCH] perf s390: Fix TEXTREL in Python extension by compiling as PIC

[James Clark]

On 10/06/2026 12:24 pm, Jens Remus wrote:
> On s390 the Python extension build fails as follows when using a linker
> that is configured to treat text relocations (TEXTREL) in shared
> libraries as error by default:
> 
>    GEN     python/perf.cpython-314-s390x-linux-gnu.so
> /usr/bin/ld.bfd: error: read-only segment has dynamic relocations
> 
> This occurrs because util/llvm-c-helpers.o is erroneously built from
> util/llvm-c-helpers.cpp without compiler option -fPIC but linked into
> the shared library (via libperf-util.a(perf-util-in.o)).
> 
> On s390, object files must be compiled as position-indepedent code (PIC)
> in order to be linked into shared libraries.  Commit a9a3f1d18a6c ("perf
> s390: Always build with -fPIC") added compiler option -fPIC to CFLAGS
> for s390, which is used in C compiles.  Add -fPIC to CXXFLAGS for s390
> as well, so that it is also used in C++ compiles.
> 
> Reported-by: Thomas Richter <tmricht@linux.ibm.com>
> Signed-off-by: Jens Remus <jremus@linux.ibm.com>
> ---
> 
> Notes (jremus):
>      This patch applies on top of the perf-tools-next tree:
>      
>        git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git  master
>      
>      Note that this resolves the issue discussed in thread "[PATCH 1/1] perf
>      build: Fix Python extension build with GCC 16 hardening":
>      https://lore.kernel.org/all/ahV2XGx_6h7upuc3@li-276bd24c-2dcc-11b2-a85c-945b6f05615c.ibm.com/T/
> 
>   tools/perf/Makefile.config | 1 +
>   1 file changed, 1 insertion(+)
> 
> diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> index 333ddd0e4bd8..33f90968c8a9 100644
> --- a/tools/perf/Makefile.config
> +++ b/tools/perf/Makefile.config
> @@ -109,6 +109,7 @@ endif
>   
>   ifeq ($(ARCH),s390)
>     CFLAGS += -fPIC
> +  CXXFLAGS += -fPIC
>   endif
>   
>   ifeq ($(ARCH),mips)

Reviewed-by: James Clark <james.clark@linaro.org>

Re: [PATCH] perf s390: Fix TEXTREL in Python extension by compiling as PIC

[Ian Rogers]

On Wed, Jun 10, 2026 at 6:39 AM James Clark <james.clark@linaro.org> wrote:
>
>
>
> On 10/06/2026 12:24 pm, Jens Remus wrote:
> > On s390 the Python extension build fails as follows when using a linker
> > that is configured to treat text relocations (TEXTREL) in shared
> > libraries as error by default:
> >
> >    GEN     python/perf.cpython-314-s390x-linux-gnu.so
> > /usr/bin/ld.bfd: error: read-only segment has dynamic relocations
> >
> > This occurrs because util/llvm-c-helpers.o is erroneously built from
> > util/llvm-c-helpers.cpp without compiler option -fPIC but linked into
> > the shared library (via libperf-util.a(perf-util-in.o)).
> >
> > On s390, object files must be compiled as position-indepedent code (PIC)
> > in order to be linked into shared libraries.  Commit a9a3f1d18a6c ("perf
> > s390: Always build with -fPIC") added compiler option -fPIC to CFLAGS
> > for s390, which is used in C compiles.  Add -fPIC to CXXFLAGS for s390
> > as well, so that it is also used in C++ compiles.
> >
> > Reported-by: Thomas Richter <tmricht@linux.ibm.com>
> > Signed-off-by: Jens Remus <jremus@linux.ibm.com>

Great! Perhaps we should add a fixes tag for backports. Perhaps:

Fixes: a9a3f1d18a6c ("perf s390: Always build with -fPIC")

Reviewed-by: Ian Rogers <irogers@google.com>

Thanks,
Ian

> > ---
> >
> > Notes (jremus):
> >      This patch applies on top of the perf-tools-next tree:
> >
> >        git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools-next.git  master
> >
> >      Note that this resolves the issue discussed in thread "[PATCH 1/1] perf
> >      build: Fix Python extension build with GCC 16 hardening":
> >      https://lore.kernel.org/all/ahV2XGx_6h7upuc3@li-276bd24c-2dcc-11b2-a85c-945b6f05615c.ibm.com/T/
> >
> >   tools/perf/Makefile.config | 1 +
> >   1 file changed, 1 insertion(+)
> >
> > diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
> > index 333ddd0e4bd8..33f90968c8a9 100644
> > --- a/tools/perf/Makefile.config
> > +++ b/tools/perf/Makefile.config
> > @@ -109,6 +109,7 @@ endif
> >
> >   ifeq ($(ARCH),s390)
> >     CFLAGS += -fPIC
> > +  CXXFLAGS += -fPIC
> >   endif
> >
> >   ifeq ($(ARCH),mips)
>
> Reviewed-by: James Clark <james.clark@linaro.org>
>

Re: [PATCH] perf s390: Fix TEXTREL in Python extension by compiling as PIC

[Arnaldo Carvalho de Melo]

On Wed, Jun 10, 2026 at 02:39:10PM +0100, James Clark wrote:
> On 10/06/2026 12:24 pm, Jens Remus wrote:
> > +++ b/tools/perf/Makefile.config
> > @@ -109,6 +109,7 @@ endif
> >   ifeq ($(ARCH),s390)
> >     CFLAGS += -fPIC
> > +  CXXFLAGS += -fPIC
> >   endif
> >   ifeq ($(ARCH),mips)
> 
> Reviewed-by: James Clark <james.clark@linaro.org>

Thanks, applied to perf-tools-next, for v7.2.

- Arnaldo