lkml.org 
[lkml]   [2020]   [Nov]   [19]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
Date
Subject[RFC PATCH] bpf: preload: Fix build error when O= is set
From
If BPF_PRELOAD is enabled, and an out-of-tree build is requested with
make O=<path>, compilation seems to fail with:

tools/scripts/Makefile.include:4: *** O=.kunit does not exist. Stop.
make[4]: *** [../kernel/bpf/preload/Makefile:8: kernel/bpf/preload/libbpf.a] Error 2
make[3]: *** [../scripts/Makefile.build:500: kernel/bpf/preload] Error 2
make[2]: *** [../scripts/Makefile.build:500: kernel/bpf] Error 2
make[2]: *** Waiting for unfinished jobs....
make[1]: *** [.../Makefile:1799: kernel] Error 2
make[1]: *** Waiting for unfinished jobs....
make: *** [Makefile:185: __sub-make] Error 2

By the looks of things, this is because the (relative path) O= passed on
the command line is being passed to the libbpf Makefile, which then
can't find the directory. Given OUTPUT= is being passed anyway, we can
work around this by explicitly setting an empty O=, which will be
ignored in favour of OUTPUT= in tools/scripts/Makefile.include.

Signed-off-by: David Gow <davidgow@google.com>
---

Hi all,

I'm not 100% sure this is the correct fix here -- it seems to work for
me, and makes some sense, but let me know if there's a better way.

One other thing worth noting is that I've been hitting this with
make allyesconfig on ARCH=um, but there's a comment in the Kconfig
suggesting that, because BPF_PRELOAD depends on !COMPILE_TEST, that
maybe it shouldn't be being built at all. I figured that it was worth
trying to fix this anyway.

Cheers,
-- David


kernel/bpf/preload/Makefile | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/kernel/bpf/preload/Makefile b/kernel/bpf/preload/Makefile
index 23ee310b6eb4..39848d296097 100644
--- a/kernel/bpf/preload/Makefile
+++ b/kernel/bpf/preload/Makefile
@@ -5,7 +5,7 @@ LIBBPF_A = $(obj)/libbpf.a
LIBBPF_OUT = $(abspath $(obj))

$(LIBBPF_A):
- $(Q)$(MAKE) -C $(LIBBPF_SRCS) OUTPUT=$(LIBBPF_OUT)/ $(LIBBPF_OUT)/libbpf.a
+ $(Q)$(MAKE) -C $(LIBBPF_SRCS) O= OUTPUT=$(LIBBPF_OUT)/ $(LIBBPF_OUT)/libbpf.a

userccflags += -I $(srctree)/tools/include/ -I $(srctree)/tools/include/uapi \
-I $(srctree)/tools/lib/ -Wno-unused-result
--
2.29.2.454.gaff20da3a2-goog
\
 
 \ /
  Last update: 2020-11-19 09:51    [W:0.100 / U:0.048 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site