Re: [PATCH] tools/testing/cxl: Don't wrap cxl_core's own exported symbols

[Richard Cheng]

On Wed, Aug 19, 2026 at 08:23:47PM +0800, shaikh kamaluddin wrote:
> On Tue, Jul 21, 2026 at 04:40:09PM +0800, Richard Cheng wrote:
> > Building cxl_test with LLVM=1 (ld.lld) fails in modpost:
> > 
> > """
> >   cxl_core: .export_symbol section references '__wrap_...', but it
> >   does not seem to be an export symbol
> > """
> > 
> > cxl_test --wraps 6 symbols that cxl_core both defines and exports.
> > GNU ld only wraps undefined references, but ld.lld also redirects
> > references to defined symbols, so cxl_core's own EXPORT_SYMBOL entries
> > get rewritten to __wrap_* and modpost rejects them.
> > 
> > cxl_core never calls these symbols, so wrap them only in the caller
> > modules via LDFLAGS_<module>.o instead of the global ldflags-y.
> > 
> > Signed-off-by: Richard Cheng <icheng@xxxxxxxxxx>
> > ---
> >  tools/testing/cxl/Kbuild | 16 ++++++++++------
> >  1 file changed, 10 insertions(+), 6 deletions(-)
> > 
> > diff --git a/tools/testing/cxl/Kbuild b/tools/testing/cxl/Kbuild
> > index 2be1df80fcc9..e49ce644b4b1 100644
> > --- a/tools/testing/cxl/Kbuild
> > +++ b/tools/testing/cxl/Kbuild
> > @@ -4,16 +4,20 @@ ldflags-y += --wrap=is_acpi_device_node
> >  ldflags-y += --wrap=acpi_evaluate_integer
> >  ldflags-y += --wrap=acpi_pci_find_root
> >  ldflags-y += --wrap=nvdimm_bus_register
> > -ldflags-y += --wrap=cxl_await_media_ready
> > -ldflags-y += --wrap=devm_cxl_add_rch_dport
> > -ldflags-y += --wrap=cxl_endpoint_parse_cdat
> > -ldflags-y += --wrap=devm_cxl_endpoint_decoders_setup
> >  ldflags-y += --wrap=hmat_get_extended_linear_cache_size
> > -ldflags-y += --wrap=devm_cxl_add_dport_by_dev
> > -ldflags-y += --wrap=devm_cxl_switch_port_decoders_setup
> >  ldflags-y += --wrap=walk_hmem_resources
> >  ldflags-y += --wrap=region_intersects
> >  ldflags-y += --wrap=region_intersects_soft_reserve
> > +wrap_cxl_core := --wrap=cxl_await_media_ready
> > +wrap_cxl_core += --wrap=devm_cxl_add_rch_dport
> > +wrap_cxl_core += --wrap=devm_cxl_add_dport_by_dev
> > +wrap_cxl_core += --wrap=devm_cxl_switch_port_decoders_setup
> > +wrap_cxl_core += --wrap=devm_cxl_endpoint_decoders_setup
> > +wrap_cxl_core += --wrap=cxl_endpoint_parse_cdat
> > +LDFLAGS_cxl_acpi.o += $(wrap_cxl_core)
> > +LDFLAGS_cxl_pmem.o += $(wrap_cxl_core)
> > +LDFLAGS_cxl_port.o += $(wrap_cxl_core)
> > +LDFLAGS_cxl_mem.o  += $(wrap_cxl_core)
> >  
> >  DRIVERS := ../../../drivers
> >  DAX_HMEM_SRC := $(DRIVERS)/dax/hmem
> > -- 
> > 2.43.0
> >
> 
> Hi Richard,
> 
> I was hitting the same tools/testing/cxl build failure on current cxl/next.
> modpost was failing on wrapped CXL symbols, for example:
> 
> .export_symbol section references '__wrap_devm_cxl_add_rch_dport',
> but it does not seem to be an export symbol
> 
> .export_symbol section references '__wrap_devm_cxl_add_dport_by_dev',
> but it does not seem to be an export symbol
> 
> .export_symbol section references '__wrap_cxl_await_media_ready',
> but it does not seem to be an export symbol
> 
> I found this patch while investigating the failure and applied it to my tree. 
> With the patch applied, the wrapped-symbol build issue is resolved and tools/testing/cxl 
> builds successfully for me.
> 
> Tested-by: Shaikh Kamaluddin <shaikhkamal2012@xxxxxxxxx>

Hi Shaikh,

Happy to hear that, appreciate for this.

Best regards,
Richard Cheng.