[PATCH 5.17 347/772] selftests/bpf: Prevent skeleton generation race

Greg Kroah-Hartman
2022-06-07T21:09:58Z

From: Andrii Nakryiko <andrii@kernel.org>

[ Upstream commit 1e2666e029e5cc2b81dbd7c85af5bcc8c80524e0 ]

Prevent "classic" and light skeleton generation rules from stomping on
each other's toes due to the use of the same <obj>.linked{1,2,3}.o
naming pattern. There is no coordination and synchronizataion between
.skel.h and .lskel.h rules, so they can easily overwrite each other's
intermediate object files, leading to errors like:

/bin/sh: line 1: 170928 Bus error (core dumped)
/data/users/andriin/linux/tools/testing/selftests/bpf/tools/sbin/bpftool gen skeleton
/data/users/andriin/linux/tools/testing/selftests/bpf/test_ksyms_weak.linked3.o
name test_ksyms_weak
> /data/users/andriin/linux/tools/testing/selftests/bpf/test_ksyms_weak.skel.h
make: *** [Makefile:507: /data/users/andriin/linux/tools/testing/selftests/bpf/test_ksyms_weak.skel.h] Error 135
make: *** Deleting file '/data/users/andriin/linux/tools/testing/selftests/bpf/test_ksyms_weak.skel.h'

Fix by using different suffix for light skeleton rule.

Fixes: c48e51c8b07a ("bpf: selftests: Add selftests for module kfunc support")
Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20220509004148.1801791-2-andrii@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
tools/testing/selftests/bpf/Makefile | 10 +++++-----
1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile
index 42ffc24e9e71..dbd95de87e88 100644
--- a/tools/testing/selftests/bpf/Makefile
+++ b/tools/testing/selftests/bpf/Makefile
@@ -407,11 +407,11 @@ $(TRUNNER_BPF_SKELS): %.skel.h: %.o $(BPFTOOL) | $(TRUNNER_OUTPUT)

$(TRUNNER_BPF_LSKELS): %.lskel.h: %.o $(BPFTOOL) | $(TRUNNER_OUTPUT)
$$(call msg,GEN-SKEL,$(TRUNNER_BINARY),$$@)
- $(Q)$$(BPFTOOL) gen object $$(<:.o=.linked1.o) $$<
- $(Q)$$(BPFTOOL) gen object $$(<:.o=.linked2.o) $$(<:.o=.linked1.o)
- $(Q)$$(BPFTOOL) gen object $$(<:.o=.linked3.o) $$(<:.o=.linked2.o)
- $(Q)diff $$(<:.o=.linked2.o) $$(<:.o=.linked3.o)
- $(Q)$$(BPFTOOL) gen skeleton -L $$(<:.o=.linked3.o) name $$(notdir $$(<:.o=_lskel)) > $$@
+ $(Q)$$(BPFTOOL) gen object $$(<:.o=.llinked1.o) $$<
+ $(Q)$$(BPFTOOL) gen object $$(<:.o=.llinked2.o) $$(<:.o=.llinked1.o)
+ $(Q)$$(BPFTOOL) gen object $$(<:.o=.llinked3.o) $$(<:.o=.llinked2.o)
+ $(Q)diff $$(<:.o=.llinked2.o) $$(<:.o=.llinked3.o)
+ $(Q)$$(BPFTOOL) gen skeleton -L $$(<:.o=.llinked3.o) name $$(notdir $$(<:.o=_lskel)) > $$@

$(TRUNNER_BPF_SKELS_LINKED): $(TRUNNER_BPF_OBJS) $(BPFTOOL) | $(TRUNNER_OUTPUT)
$$(call msg,LINK-BPF,$(TRUNNER_BINARY),$$(@:.skel.h=.o))
--
2.35.1