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Date:   Wed,  6 Dec 2023 02:36:57 -0800
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Subject: [PATCH v6 3/5] selftests/mm: call uffd_test_ctx_clear at the end of
 the test
From:   Suren Baghdasaryan <surenb@google.com>
To:     akpm@linux-foundation.org
Cc:     viro@zeniv.linux.org.uk, brauner@kernel.org, shuah@kernel.org,
        aarcange@redhat.com, lokeshgidra@google.com, peterx@redhat.com,
        david@redhat.com, ryan.roberts@arm.com, hughd@google.com,
        mhocko@suse.com, axelrasmussen@google.com, rppt@kernel.org,
        willy@infradead.org, Liam.Howlett@oracle.com, jannh@google.com,
        zhangpeng362@huawei.com, bgeffon@google.com,
        kaleshsingh@google.com, ngeoffray@google.com, jdduke@google.com,
        surenb@google.com, linux-mm@kvack.org,
        linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-kselftest@vger.kernel.org, kernel-team@android.com
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Precedence: bulk

uffd_test_ctx_clear() is being called from uffd_test_ctx_init() to unmap
areas used in the previous test run. This approach is problematic because
while unmapping areas uffd_test_ctx_clear() uses page_size and nr_pages
which might differ from one test run to another.
Fix this by calling uffd_test_ctx_clear() after each test is done.

Signed-off-by: Suren Baghdasaryan <surenb@google.com>
Reviewed-by: Peter Xu <peterx@redhat.com>
Reviewed-by: Axel Rasmussen <axelrasmussen@google.com>
---
 tools/testing/selftests/mm/uffd-common.c     | 4 +---
 tools/testing/selftests/mm/uffd-common.h     | 1 +
 tools/testing/selftests/mm/uffd-stress.c     | 5 ++++-
 tools/testing/selftests/mm/uffd-unit-tests.c | 1 +
 4 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/mm/uffd-common.c b/tools/testing/selftests/mm/uffd-common.c
index 02b89860e193..583e5a4cc0fd 100644
--- a/tools/testing/selftests/mm/uffd-common.c
+++ b/tools/testing/selftests/mm/uffd-common.c
@@ -262,7 +262,7 @@ static inline void munmap_area(void **area)
 	*area = NULL;
 }
 
-static void uffd_test_ctx_clear(void)
+void uffd_test_ctx_clear(void)
 {
 	size_t i;
 
@@ -298,8 +298,6 @@ int uffd_test_ctx_init(uint64_t features, const char **errmsg)
 	unsigned long nr, cpu;
 	int ret;
 
-	uffd_test_ctx_clear();
-
 	ret = uffd_test_ops->allocate_area((void **)&area_src, true);
 	ret |= uffd_test_ops->allocate_area((void **)&area_dst, false);
 	if (ret) {
diff --git a/tools/testing/selftests/mm/uffd-common.h b/tools/testing/selftests/mm/uffd-common.h
index 7c4fa964c3b0..870776b5a323 100644
--- a/tools/testing/selftests/mm/uffd-common.h
+++ b/tools/testing/selftests/mm/uffd-common.h
@@ -105,6 +105,7 @@ extern uffd_test_ops_t *uffd_test_ops;
 
 void uffd_stats_report(struct uffd_args *args, int n_cpus);
 int uffd_test_ctx_init(uint64_t features, const char **errmsg);
+void uffd_test_ctx_clear(void);
 int userfaultfd_open(uint64_t *features);
 int uffd_read_msg(int ufd, struct uffd_msg *msg);
 void wp_range(int ufd, __u64 start, __u64 len, bool wp);
diff --git a/tools/testing/selftests/mm/uffd-stress.c b/tools/testing/selftests/mm/uffd-stress.c
index 469e0476af26..7e83829bbb33 100644
--- a/tools/testing/selftests/mm/uffd-stress.c
+++ b/tools/testing/selftests/mm/uffd-stress.c
@@ -323,8 +323,10 @@ static int userfaultfd_stress(void)
 		uffd_stats_reset(args, nr_cpus);
 
 		/* bounce pass */
-		if (stress(args))
+		if (stress(args)) {
+			uffd_test_ctx_clear();
 			return 1;
+		}
 
 		/* Clear all the write protections if there is any */
 		if (test_uffdio_wp)
@@ -354,6 +356,7 @@ static int userfaultfd_stress(void)
 
 		uffd_stats_report(args, nr_cpus);
 	}
+	uffd_test_ctx_clear();
 
 	return 0;
 }
diff --git a/tools/testing/selftests/mm/uffd-unit-tests.c b/tools/testing/selftests/mm/uffd-unit-tests.c
index 2709a34a39c5..e7d43c198041 100644
--- a/tools/testing/selftests/mm/uffd-unit-tests.c
+++ b/tools/testing/selftests/mm/uffd-unit-tests.c
@@ -1319,6 +1319,7 @@ int main(int argc, char *argv[])
 				continue;
 			}
 			test->uffd_fn(&args);
+			uffd_test_ctx_clear();
 		}
 	}
 
-- 
2.43.0.rc2.451.g8631bc7472-goog