Subject: Re: linux-next: build failure after merge of the bpf-next tree

From: Jiri Olsa <[email-masked]>
Date: Tue, 14 Jul 2020 10:31:33 +0200

On Tue, Jul 14, 2020 at 08:16:54AM +0200, Jiri Olsa wrote:
> On Tue, Jul 14, 2020 at 12:22:47PM +1000, Stephen Rothwell wrote:
> > Hi all,
> > 
> > After merging the bpf-next tree, today's linux-next build (arm
> > multi_v7_defconfig) failed like this:
> > 
> > tmp/ccsqpVCY.s: Assembler messages:
> > tmp/ccsqpVCY.s:78: Error: unrecognized symbol type ""
> > tmp/ccsqpVCY.s:91: Error: unrecognized symbol type ""
> > 
> > I don't know what has caused this (I guess maybe the resolve_btfids
> > branch).
> > 
> > I have used the bpf-next tree from next-20200713 for today.
> 
> ok, trying to reproduce

damn crossbuilds.. change below fixes it for me,
will do some more testing and post it today

jirka

---
diff --git a/include/linux/btf_ids.h b/include/linux/btf_ids.h
index fe019774f8a7..8b9194e22c7c 100644
--- a/include/linux/btf_ids.h
+++ b/include/linux/btf_ids.h
@@ -21,7 +21,7 @@
 asm(							\
 ".pushsection " BTF_IDS_SECTION ",\"a\";       \n"	\
 ".local " #symbol " ;                          \n"	\
-".type  " #symbol ", @object;                  \n"	\
+".type  " #symbol ", STT_OBJECT;               \n"	\
 ".size  " #symbol ", 4;                        \n"	\
 #symbol ":                                     \n"	\
 ".zero 4                                       \n"	\
diff --git a/tools/bpf/resolve_btfids/Makefile b/tools/bpf/resolve_btfids/Makefile
index 948378ca73d4..a88cd4426398 100644
--- a/tools/bpf/resolve_btfids/Makefile
+++ b/tools/bpf/resolve_btfids/Makefile
@@ -16,6 +16,20 @@ else
   MAKEFLAGS=--no-print-directory
 endif
 
+# always use the host compiler
+ifneq ($(LLVM),)
+HOSTAR  ?= llvm-ar
+HOSTCC  ?= clang
+HOSTLD  ?= ld.lld
+else
+HOSTAR  ?= ar
+HOSTCC  ?= gcc
+HOSTLD  ?= ld
+endif
+AR       = $(HOSTAR)
+CC       = $(HOSTCC)
+LD       = $(HOSTLD)
+
 OUTPUT ?= $(srctree)/tools/bpf/resolve_btfids/
 
 LIBBPF_SRC := $(srctree)/tools/lib/bpf/