From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id F21ED3A7859; Tue, 24 Feb 2026 16:15:20 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771949721; cv=none; b=UDRsa5V3sQwvU4GJ+mCpAsXZwg4SekKL8XwACnwpeC7pSsJ1Gshp97SowNKy1SRZHJqJhFdl2igeQ12NJGCuH/EbexZFA2XPM37QiyLGgfSe6Bi/v1Z6e8pGDizDVBHixJLLArSbNRZDDTPLh7V7rExeozIKdhMKRAyLwKKDfBQ= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1771949721; c=relaxed/simple; bh=e8ui64+5y6ni0ao76yPSNCWiKuk4eYNlPnlFLGkLqgY=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=rtI28Bl6+cOtyb1KeqD0kAUjoZXL7hfXikw9my01QN8G70I3/LkabeTGGyRUd4Z2lFYxjUk6gJQO2hZJEQUIIrWQyp2sqSn1pS//tL6kjzGhAYc2alepNsnqNLnwCdn/iefjzFdi7cnZkmx6cfFOBrBqRh5KLr/PktbF/jIV3vs= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=azNAiacH; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="azNAiacH" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 49F13C19422; Tue, 24 Feb 2026 16:15:16 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1771949720; bh=e8ui64+5y6ni0ao76yPSNCWiKuk4eYNlPnlFLGkLqgY=; h=Date:Subject:To:Cc:References:From:In-Reply-To:From; b=azNAiacH9BhxTQimtBeqHMlpeQUoZsEpZLXn1YICn7l1qNRc0bXw5ZNXNvZEkNaKF ed6DxGSDyfjlPR3zJDNbyYWTqNxfL18tLHVtVEwFI+P1lW7mbE9iTt7JX7bFvBfEzw u4yubE0NpU2te77jLFp8tJVkbnaaXq8PNNgc7izpO8wCyMVZ3pvs56y/OYpGPU9P6i C8isb7MYNNEhb3OLQrorD5VSHPFCAkawZ54RMSFH4HrLVON5NqY985UkHrhwBc88iC Hzj3ZK1tDD/AZIC4D17+0ABtjvdTgSfaTCrwm5aSTiP/6VdqN0O5CEhEPCrLM2LLIw dO3fnO0y4xC3g== Message-ID: Date: Tue, 24 Feb 2026 17:15:14 +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] selftests/mm: Fix soft-dirty kselftest supported check To: Audra Mitchell , linux-kselftest@vger.kernel.org Cc: akpm@linux-foundation.org, lorenzo.stoakes@oracle.com, Liam.Howlett@oracle.com, vbabka@suse.cz, rppt@kernel.org, surenb@google.com, mhocko@suse.com, shuah@kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20260218184210.206466-1-audra@redhat.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 2/18/26 19:42, Audra Mitchell wrote: > On architectures with separate user address space, such as s390 or > those without an MMU, the call to __access_ok will return true. Where is this __access_ok() you mention here? Somewhere in fs/proc/task_mmu.c? > The soft-dirty test attempts to check if the PAGEMAP_SCAN feature > is supported by providing an invalid address and expecting > __access_ok to return false, thus throwing an EFAULT error on return. Where in the soft-dirty test is that triggered? I'm wondering whether the soft-dirty test should be adjusted, but I did not yet understand from where this behavior is triggered. > Because of this assumption, this check will always fail for the > architectures aforementioned. Update the supported check to handle > the return being zero for these types of cases. It would be great to include the output of an actual test case (soft-dirty?) that is affected by this before/after your change (likely on s390x where it seems to trigger). Do we have a Fixes: tag? > > Signed-off-by: Audra Mitchell > --- > tools/testing/selftests/mm/vm_util.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/mm/vm_util.c b/tools/testing/selftests/mm/vm_util.c > index d954bf91afd5..3bb7d322101c 100644 > --- a/tools/testing/selftests/mm/vm_util.c > +++ b/tools/testing/selftests/mm/vm_util.c > @@ -77,10 +77,8 @@ static bool pagemap_scan_supported(int fd, char *start) > > /* Provide an invalid address in order to trigger EFAULT. */ > ret = __pagemap_scan_get_categories(fd, start, (struct page_region *) ~0UL); > - if (ret == 0) > - ksft_exit_fail_msg("PAGEMAP_SCAN succeeded unexpectedly\n"); > > - supported = errno == EFAULT; > + supported = (ret == 0) || (errno == EFAULT); > > return supported; > } -- Cheers, David