On 2025/12/16 22:26, Kevin Brodsky wrote:
Commit 96ed62ea0298 ("mm: page_frag: fix a compile error when kernel is not compiled") introduced a check to avoid attempting to build the page_frag module if <linux/page_frag_cache.h> is missing.
Unfortunately this check only works if KDIR points to /lib/modules/... or an in-tree kernel build. It always fails if KDIR points to an out-of-tree build (i.e. when the kernel was built with O=$KDIR make) because only generated headers are present under $KDIR/include/ in that case.
<linux/page_frag_cache.h> was added more than a year ago (v6.13) so we can probably live without that check.
As some commercial OS still uses v6.6, I am wondering if we need that check for a little longer, is it possible to do something like below to avoid the flaky check?
@@ -46,7 +46,8 @@ CFLAGS += -U_FORTIFY_SOURCE
KDIR ?= /lib/modules/$(shell uname -r)/build ifneq (,$(wildcard $(KDIR)/Module.symvers)) -ifneq (,$(wildcard $(KDIR)/include/linux/page_frag_cache.h)) +KSRC := $(shell readlink -f $(KDIR)/source 2>/dev/null || echo $(KDIR)) +ifneq (,$(wildcard $(KSRC)/include/linux/page_frag_cache.h)) TEST_GEN_MODS_DIR := page_frag else PAGE_FRAG_WARNING = "missing page_frag_cache.h, please use a newer kernel"
Cc: Paolo Abeni pabeni@redhat.com Cc: Yunsheng Lin linyunsheng@huawei.com Signed-off-by: Kevin Brodsky kevin.brodsky@arm.com
tools/testing/selftests/mm/Makefile | 4 ---- 1 file changed, 4 deletions(-)
diff --git a/tools/testing/selftests/mm/Makefile b/tools/testing/selftests/mm/Makefile index eaf9312097f7..aba51fcac752 100644 --- a/tools/testing/selftests/mm/Makefile +++ b/tools/testing/selftests/mm/Makefile @@ -46,12 +46,8 @@ CFLAGS += -U_FORTIFY_SOURCE KDIR ?= /lib/modules/$(shell uname -r)/build ifneq (,$(wildcard $(KDIR)/Module.symvers)) -ifneq (,$(wildcard $(KDIR)/include/linux/page_frag_cache.h)) TEST_GEN_MODS_DIR := page_frag else -PAGE_FRAG_WARNING = "missing page_frag_cache.h, please use a newer kernel" -endif -else PAGE_FRAG_WARNING = "missing Module.symvers, please have the kernel built first" endif