From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id 87F0D33A038; Thu, 18 Dec 2025 13:24:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766064259; cv=none; b=oBMeCMd+1+uHUgQLydjQPh1mQJ07nQmN1tIob2g/KSQp8OTMMwEfdIGsQ+ZW78KqWZovhLXdLz8BLA84mxyuexlkOZSsb32hWhp0gxHkru3+cVgX+FLDUlHVTY25xB8OopOClSdmhpAxQQhU5ItHphM4nIZU4ZdHUmtGk3DA6TM= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1766064259; c=relaxed/simple; bh=DlCDfZgm5JsmTafpliNDNHYQsLVdY8Jj7Nu3gUmzK2M=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=tufLkujP4D14ZHakJ6LK9OUs/OiJzIerw+QNuv7MJ3SYBiJtHcqQ3Z+oy1mKE+hep2l3SZhGQoeYl7CkPjuLXgnq5B6NH7uUdDUp3t+34aVUto7ntunYbTZywE16emomzZ6fELGROfQjuRKkbuK0y+p45wDZUQNzr7gX/PY38mo= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 98AE0FEC; Thu, 18 Dec 2025 05:24:08 -0800 (PST) Received: from [10.57.45.71] (unknown [10.57.45.71]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 3B5F13F73F; Thu, 18 Dec 2025 05:24:13 -0800 (PST) Message-ID: Date: Thu, 18 Dec 2025 14:24:10 +0100 Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH 1/4] selftests/mm: remove flaky header check To: Mark Brown Cc: linux-mm@kvack.org, linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org, Andrew Morton , David Hildenbrand , Lorenzo Stoakes , Ryan Roberts , Shuah Khan , Paolo Abeni , Yunsheng Lin References: <20251216142633.2401447-1-kevin.brodsky@arm.com> <20251216142633.2401447-2-kevin.brodsky@arm.com> <5f866c1a-c8cd-4dc6-b312-9017cef89920@sirena.org.uk> From: Kevin Brodsky Content-Language: en-GB In-Reply-To: <5f866c1a-c8cd-4dc6-b312-9017cef89920@sirena.org.uk> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 17/12/2025 11:04, Mark Brown wrote: > On Tue, Dec 16, 2025 at 02:26:30PM +0000, 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 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. >> >> was added more than a year ago (v6.13) so >> we can probably live without that check. > More generally building selftests with random older kernel versions > isn't really something that's expected to be robust: I suppose that Documentation/dev-tools/kselftest.rst talks about *running* against older kernels, not *building* against them. That said, we are dealing with an out-of-tree kernel module here, so the two are essentially the same... Yunsheng suggested an updated check that I think is reasonable, maybe it is a reasonable compromise? - Kevin