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Message-ID: <e9cdb144-70c7-6596-2377-e675635c94e0@redhat.com>
Date:   Mon, 7 Aug 2023 17:36:44 +0200
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Subject: Re: [PATCH v3 7/7] selftest/mm: ksm_functional_tests: Add PROT_NONE
 test
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To:     linux-kernel@vger.kernel.org,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
        kvm@vger.kernel.org, linux-kselftest@vger.kernel.org,
        Linus Torvalds <torvalds@linux-foundation.org>,
        liubo <liubo254@huawei.com>, Peter Xu <peterx@redhat.com>,
        Matthew Wilcox <willy@infradead.org>,
        Hugh Dickins <hughd@google.com>,
        Jason Gunthorpe <jgg@ziepe.ca>,
        John Hubbard <jhubbard@nvidia.com>,
        Mel Gorman <mgorman@suse.de>, Shuah Khan <shuah@kernel.org>,
        Paolo Bonzini <pbonzini@redhat.com>
References: <20230803143208.383663-1-david@redhat.com>
 <20230803143208.383663-8-david@redhat.com>
From:   David Hildenbrand <david@redhat.com>
Organization: Red Hat
In-Reply-To: <20230803143208.383663-8-david@redhat.com>
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On 03.08.23 16:32, David Hildenbrand wrote:
> Let's test whether merging and unmerging in PROT_NONE areas works as
> expected.
> 
> Pass a page protection to mmap_and_merge_range(), which will trigger
> an mprotect() after writing to the pages, but before enabling merging.
> 
> Make sure that unsharing works as expected, by performing a ptrace write
> (using /proc/self/mem) and by setting MADV_UNMERGEABLE.
> 
> Note that this implicitly tests that ptrace writes in an inaccessible
> (PROT_NONE) mapping work as expected.
> 
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---

Andrew, can you squash the following?

 From c2be7c02cb96b9189a52a5937821600ef4e259bd Mon Sep 17 00:00:00 2001
From: David Hildenbrand <david@redhat.com>
Date: Mon, 7 Aug 2023 17:33:54 +0200
Subject: [PATCH] Fixup: selftest/mm: ksm_functional_tests: Add PROT_NONE test

As noted by Peter, we should be using sizeof(i) in test_prot_none().

Signed-off-by: David Hildenbrand <david@redhat.com>
---
  tools/testing/selftests/mm/ksm_functional_tests.c | 2 +-
  1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/tools/testing/selftests/mm/ksm_functional_tests.c b/tools/testing/selftests/mm/ksm_functional_tests.c
index 8fa4889ab4f3..901e950f9138 100644
--- a/tools/testing/selftests/mm/ksm_functional_tests.c
+++ b/tools/testing/selftests/mm/ksm_functional_tests.c
@@ -516,7 +516,7 @@ static void test_prot_none(void)
  	/* Store a unique value in each page on one half using ptrace */
  	for (i = 0; i < size / 2; i += pagesize) {
  		lseek(mem_fd, (uintptr_t) map + i, SEEK_SET);
-		if (write(mem_fd, &i, sizeof(size)) != sizeof(size)) {
+		if (write(mem_fd, &i, sizeof(i)) != sizeof(i)) {
  			ksft_test_result_fail("ptrace write failed\n");
  			goto unmap;
  		}
-- 
2.41.0


-- 
Cheers,

David / dhildenb