linux-kernel - Re: [PATCH 1/4] selftests/mm: remove flaky header check

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <b62c18a2-7036-4cca-a3e6-8a873a2ca832@huawei.com>
Date: Wed, 17 Dec 2025 11:18:20 +0800
From: Yunsheng Lin <linyunsheng@...wei.com>
To: Kevin Brodsky <kevin.brodsky@....com>, <linux-mm@...ck.org>,
	<linux-kselftest@...r.kernel.org>
CC: <linux-kernel@...r.kernel.org>, Andrew Morton <akpm@...ux-foundation.org>,
	David Hildenbrand <david@...nel.org>, Lorenzo Stoakes
	<lorenzo.stoakes@...cle.com>, Mark Brown <broonie@...nel.org>, Ryan Roberts
	<ryan.roberts@....com>, Shuah Khan <shuah@...nel.org>, Paolo Abeni
	<pabeni@...hat.com>
Subject: Re: [PATCH 1/4] selftests/mm: remove flaky header check

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@...hat.com>
> Cc: Yunsheng Lin <linyunsheng@...wei.com>
> Signed-off-by: Kevin Brodsky <kevin.brodsky@....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
>