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From: Axel Rasmussen <axelrasmussen@google.com>
To: Alexander Viro <viro@zeniv.linux.org.uk>,
	Andrea Arcangeli <aarcange@redhat.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Hugh Dickins <hughd@google.com>,
	Jerome Glisse <jglisse@redhat.com>, Joe Perches <joe@perches.com>,
	Lokesh Gidra <lokeshgidra@google.com>,
	Mike Kravetz <mike.kravetz@oracle.com>,
	Mike Rapoport <rppt@linux.vnet.ibm.com>,
	Peter Xu <peterx@redhat.com>, Shaohua Li <shli@fb.com>,
	Shuah Khan <shuah@kernel.org>,
	Stephen Rothwell <sfr@canb.auug.org.au>,
	Wang Qing <wangqing@vivo.com>
Cc: linux-api@vger.kernel.org, linux-fsdevel@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-mm@kvack.org, Axel Rasmussen <axelrasmussen@google.com>,
	Brian Geffon <bgeffon@google.com>,
	"Dr . David Alan Gilbert" <dgilbert@redhat.com>,
	Mina Almasry <almasrymina@google.com>,
	Oliver Upton <oupton@google.com>
Subject: [PATCH v2 8/9] userfaultfd/selftests: exercise minor fault handling shmem support
Date: Mon, 12 Apr 2021 22:17:20 -0700
Message-ID: <20210413051721.2896915-9-axelrasmussen@google.com> (raw)
In-Reply-To: <20210413051721.2896915-1-axelrasmussen@google.com>

Enable test_uffdio_minor for test_type == TEST_SHMEM, and modify the
test slightly to pass in / check for the right feature flags.

Signed-off-by: Axel Rasmussen <axelrasmussen@google.com>
---
 tools/testing/selftests/vm/userfaultfd.c | 29 ++++++++++++++++++++----
 1 file changed, 25 insertions(+), 4 deletions(-)

diff --git a/tools/testing/selftests/vm/userfaultfd.c b/tools/testing/selftests/vm/userfaultfd.c
index 0ff01f437a39..0830f155e6c2 100644
--- a/tools/testing/selftests/vm/userfaultfd.c
+++ b/tools/testing/selftests/vm/userfaultfd.c
@@ -484,6 +484,7 @@ static void wp_range(int ufd, __u64 start, __u64 len, bool wp)
 static void continue_range(int ufd, __u64 start, __u64 len)
 {
 	struct uffdio_continue req;
+	int ret;
 
 	req.range.start = start;
 	req.range.len = len;
@@ -492,6 +493,17 @@ static void continue_range(int ufd, __u64 start, __u64 len)
 	if (ioctl(ufd, UFFDIO_CONTINUE, &req))
 		err("UFFDIO_CONTINUE failed for address 0x%" PRIx64,
 		    (uint64_t)start);
+
+	/*
+	 * Error handling within the kernel for continue is subtly different
+	 * from copy or zeropage, so it may be a source of bugs. Trigger an
+	 * error (-EEXIST) on purpose, to verify doing so doesn't cause a BUG.
+	 */
+	req.mapped = 0;
+	ret = ioctl(ufd, UFFDIO_CONTINUE, &req);
+	if (ret >= 0 || req.mapped != -EEXIST)
+		err("failed to exercise UFFDIO_CONTINUE error handling, ret=%d, mapped=%" PRId64,
+		    ret, (int64_t) req.mapped);
 }
 
 static void *locking_thread(void *arg)
@@ -1196,7 +1208,7 @@ static int userfaultfd_minor_test(void)
 	void *expected_page;
 	char c;
 	struct uffd_stats stats = { 0 };
-	uint64_t features = UFFD_FEATURE_MINOR_HUGETLBFS;
+	uint64_t req_features, features_out;
 
 	if (!test_uffdio_minor)
 		return 0;
@@ -1204,10 +1216,18 @@ static int userfaultfd_minor_test(void)
 	printf("testing minor faults: ");
 	fflush(stdout);
 
-	if (uffd_test_ctx_clear() || uffd_test_ctx_init_ext(&features))
+	if (test_type == TEST_HUGETLB)
+		req_features = UFFD_FEATURE_MINOR_HUGETLBFS;
+	else if (test_type == TEST_SHMEM)
+		req_features = UFFD_FEATURE_MINOR_SHMEM;
+	else
+		return 1;
+
+	features_out = req_features;
+	if (uffd_test_ctx_clear() || uffd_test_ctx_init_ext(&features_out))
 		return 1;
-	/* If kernel reports the feature isn't supported, skip the test. */
-	if (!(features & UFFD_FEATURE_MINOR_HUGETLBFS)) {
+	/* If kernel reports required features aren't supported, skip test. */
+	if ((features_out & req_features) != req_features) {
 		printf("skipping test due to lack of feature support\n");
 		fflush(stdout);
 		return 0;
@@ -1442,6 +1462,7 @@ static void set_test_type(const char *type)
 		map_shared = true;
 		test_type = TEST_SHMEM;
 		uffd_test_ops = &shmem_uffd_test_ops;
+		test_uffdio_minor = true;
 	} else {
 		err("Unknown test type: %s", type);
 	}
-- 
2.31.1.295.g9ea45b61b8-goog


  parent reply index

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-13  5:17 [PATCH v2 0/9] userfaultfd: add minor fault handling for shmem Axel Rasmussen
2021-04-13  5:17 ` [PATCH v2 1/9] userfaultfd/hugetlbfs: avoid including userfaultfd_k.h in hugetlb.h Axel Rasmussen
2021-04-14  6:43   ` Hugh Dickins
2021-04-13  5:17 ` [PATCH v2 2/9] userfaultfd/shmem: combine shmem_{mcopy_atomic,mfill_zeropage}_pte Axel Rasmussen
2021-04-14  6:51   ` Hugh Dickins
2021-04-13  5:17 ` [PATCH v2 3/9] userfaultfd/shmem: support minor fault registration for shmem Axel Rasmussen
2021-04-13 20:43   ` Peter Xu
2021-04-14  7:36   ` Hugh Dickins
2021-04-14 18:51     ` Peter Xu
2021-04-13  5:17 ` [PATCH v2 4/9] userfaultfd/shmem: support UFFDIO_CONTINUE " Axel Rasmussen
2021-04-16 23:47   ` Hugh Dickins
2021-04-20 18:05     ` Axel Rasmussen
2021-04-13  5:17 ` [PATCH v2 5/9] userfaultfd/selftests: use memfd_create for shmem test type Axel Rasmussen
2021-04-13 20:16   ` Peter Xu
2021-04-13  5:17 ` [PATCH v2 6/9] userfaultfd/selftests: create alias mappings in the shmem test Axel Rasmussen
2021-04-13 20:17   ` Peter Xu
2021-04-13  5:17 ` [PATCH v2 7/9] userfaultfd/selftests: reinitialize test context in each test Axel Rasmussen
2021-04-13 20:15   ` Peter Xu
2021-04-15 18:03     ` Axel Rasmussen
2021-04-13  5:17 ` Axel Rasmussen [this message]
2021-04-13  5:17 ` [PATCH v2 9/9] userfaultfd/shmem: modify shmem_mcopy_atomic_pte to use install_ptes Axel Rasmussen
2021-04-17  0:34   ` Hugh Dickins
2021-04-20 18:43     ` Axel Rasmussen

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