From: Li Wang <liwang@redhat.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: david@kernel.org, ljs@kernel.org, Liam.Howlett@oracle.com,
vbabka@kernel.org, rppt@kernel.org, surenb@google.com,
mhocko@suse.com, shuah@kernel.org, linux-mm@kvack.org,
linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/4] selftests/lib.mk: set PWD from CURDIR to avoid wrong extmod path
Date: Tue, 31 Mar 2026 15:19:05 +0800 [thread overview]
Message-ID: <act1ae44xGmG86xT@redhat.com> (raw)
In-Reply-To: <20260330223025.4ad1cdb9b79e242f01d8b83d@linux-foundation.org>
On Mon, Mar 30, 2026 at 10:30:25PM -0700, Andrew Morton wrote:
> 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.
No problem, actually I wasn't able to reproduce it, the patch just worked
out based on your description. We can kick out it from patchset unless
someone confirm it is needed.
--
Regards,
Li Wang
next prev parent reply other threads:[~2026-03-31 7:19 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-03-31 4:01 [PATCH 1/4] selftests/mm: respect build verbosity settings for 32/64-bit targets Li Wang
2026-03-31 4:01 ` [PATCH 2/4] selftests/mm: serialize local_config generation for parallel builds Li Wang
2026-03-31 5:29 ` Andrew Morton
2026-03-31 9:16 ` Li Wang
2026-03-31 4:01 ` [PATCH 3/4] selftests/lib.mk: set PWD from CURDIR to avoid wrong extmod path Li Wang
2026-03-31 5:30 ` Andrew Morton
2026-03-31 7:19 ` Li Wang [this message]
2026-03-31 4:01 ` [PATCH 4/4] selftests/mm: fix cow/gup_longterm link failures when liburing flags are missing Li Wang
2026-03-31 7:13 ` Li Wang
2026-04-01 13:44 ` David Hildenbrand (Arm)
2026-03-31 5:29 ` [PATCH 1/4] selftests/mm: respect build verbosity settings for 32/64-bit targets Andrew Morton
2026-03-31 9:50 ` Li Wang
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