If 'readelf -n' encounters a note it does not recognize it emits a
warning. This for example happens when inspecting a compat vDSO for
which the main kernel toolchain was not used.
However the relevant build ID note is always readable, so the
warnings are pointless.

Hide the warnings to make it possible to extract build IDs for more
architectures in the future.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Reviewed-by: Nicolas Schier <nsc@kernel.org>
---
 scripts/Makefile.vdsoinst | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/scripts/Makefile.vdsoinst b/scripts/Makefile.vdsoinst
index 214c561651cf..aed153b3120b 100644
--- a/scripts/Makefile.vdsoinst
+++ b/scripts/Makefile.vdsoinst
@@ -21,7 +21,7 @@ $$(dest): $(1) FORCE
 
 # Some architectures create .build-id symlinks
 ifneq ($(filter arm s390 sparc x86, $(SRCARCH)),)
-build-id-file := $$(shell $(READELF) -n $(1) | sed -n 's@^.*Build ID: \(..\)\(.*\)@\1/\2@p')
+build-id-file := $$(shell $(READELF) -n $(1) 2>/dev/null | sed -n 's@^.*Build ID: \(..\)\(.*\)@\1/\2@p')
 link := $(install-dir)/.build-id/$$(build-id-file).debug
 
 __default: $$(link)

-- 
2.53.0