Re: [PATCH 3/4] selftests/lib.mk: set PWD from CURDIR to avoid wrong extmod path

[Andrew Morton <akpm@linux-foundation.org>]

On Tue, 31 Mar 2026 12:01:55 +0800 Li Wang <liwang@redhat.com> wrote:

> When running selftests from the kernel top-level (e.g. make kselftest-all),
> sub-makes might still inherit the caller's PWD from the environment.
> 
> Some selftests use $(PWD) in recursive kbuild invocations, which can
> then incorrectly resolve to the kernel top directory instead of the
> current test directory.
> 
> In that case, kbuild may generate an external-module wrapper Makefile in
> the wrong location, potentially clobbering the top-level Makefile and
> causing recursive include failures ("Too many open files").
> 
> Export PWD := $(CURDIR) in selftests/lib.mk so $(PWD) always matches the
> actual current selftest directory.
> 
> Reported-by: Andrew Morton <akpm@linux-foundation.org>
> Signed-off-by: Li Wang <liwang@redhat.com>

I couldn't clearly figure out what I was doing to cause kbuild to
destroy my top-level Makefile.  It happened three times and it wasn't
fun so I Stopped Doing That.  

I tried a bunch of things *without* this patch and of course, Makefile
is still intact.  So I cannot confirm or deny, sorry.

I've switched my script so I'll henceforth be running -j100, shall keep
an eye on things.

I have no comment on [4/4] - it addresses something I haven't seen.

I'll assume this patchset will be handled via the kbuild tree.