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 BDA15286D63; Thu, 22 Jan 2026 06:16:07 +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=1769062570; cv=none; b=roqz/fd2wvfIrrA3yAZ9XvqIbcn+AAC9ttubEjwPOARd7pAhPBwHmzUn8JheHBP4H5tbVhS18XRFtI0K2xyK5vkDmF04iaNUnFJpQqXwMZxTgu1YCfHjG5bWPJhOnlOJfLufNog9+m1W/91HXXxRPifaeENWujlAhNkiBtlMC6g= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1769062570; c=relaxed/simple; bh=0axUIC+JvkCjnkJ5W4oGGIcrOJHUgpE1/rzuLhyZIL4=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=YPY9Kf+fkAVlc3frEZoZdHXr3WHrbgXQms8eiACNnXzXpSxbK840tuD3SF0Gc3yHMh1jIQk1Y/Ne6jKG6wZUwGgENl8aPhlqwFzVraAHjqw8itja47ZOlJ+0spXthy/q1NFbMVq3x7woYdaXyok943D8mcX4q/h0R5yQY6G6zmU= 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 1B9D81476; Wed, 21 Jan 2026 22:16:00 -0800 (PST) Received: from [10.164.18.63] (MacBook-Pro.blr.arm.com [10.164.18.63]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AC71D3F740; Wed, 21 Jan 2026 22:16:03 -0800 (PST) Message-ID: Date: Thu, 22 Jan 2026 11:46:01 +0530 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 v2 6/8] selftests/mm: fix faulting-in code in pagemap_ioctl test To: Kevin Brodsky , linux-mm@kvack.org, linux-kselftest@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Andrew Morton , David Hildenbrand , Lorenzo Stoakes , Mark Brown , Ryan Roberts , Shuah Khan , Usama Anjum References: <20260107164842.3289559-1-kevin.brodsky@arm.com> <20260107164842.3289559-7-kevin.brodsky@arm.com> Content-Language: en-US From: Dev Jain In-Reply-To: <20260107164842.3289559-7-kevin.brodsky@arm.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 07/01/26 10:18 pm, Kevin Brodsky wrote: > One of the pagemap_ioctl tests attempts to fault in pages by > memcpy()'ing them to an unused buffer. This probably worked > originally, but since commit 46036188ea1f ("selftests/mm: build with > -O2") the compiler is free to optimise away that unused buffer and > the memcpy() with it. As a result there might not be any resident > page in the mapping and the test may fail. > > We don't need to copy all that memory anyway. Just fault in every > page. > > Cc: Usama Anjum > Signed-off-by: Kevin Brodsky Reviewed-by: Dev Jain > --- > tools/testing/selftests/mm/pagemap_ioctl.c | 4 +--- > 1 file changed, 1 insertion(+), 3 deletions(-) > > diff --git a/tools/testing/selftests/mm/pagemap_ioctl.c b/tools/testing/selftests/mm/pagemap_ioctl.c > index 2cb5441f29c7..80d7c391f8f5 100644 > --- a/tools/testing/selftests/mm/pagemap_ioctl.c > +++ b/tools/testing/selftests/mm/pagemap_ioctl.c > @@ -1056,7 +1056,6 @@ int sanity_tests(void) > struct page_region *vec; > char *mem, *fmem; > struct stat sbuf; > - char *tmp_buf; > > /* 1. wrong operation */ > mem_size = 10 * page_size; > @@ -1167,8 +1166,7 @@ int sanity_tests(void) > if (fmem == MAP_FAILED) > ksft_exit_fail_msg("error nomem %d %s\n", errno, strerror(errno)); > > - tmp_buf = malloc(sbuf.st_size); > - memcpy(tmp_buf, fmem, sbuf.st_size); > + force_read_pages_in_range(fmem, sbuf.st_size); > > ret = pagemap_ioctl(fmem, sbuf.st_size, vec, vec_size, 0, 0, > 0, PAGEMAP_NON_WRITTEN_BITS, 0, PAGEMAP_NON_WRITTEN_BITS);