The patch titled
Subject: userfaultfd/selftests: exercise minor fault handling shmem support
has been added to the -mm tree. Its filename is
userfaultfd-selftests-exercise-minor-fault-handling-shmem-support.patch
This patch should soon appear at
https://ozlabs.org/~akpm/mmots/broken-out/userfaultfd-selftests-exercise-minor-fault-handling-shmem-support.patch
and later at
https://ozlabs.org/~akpm/mmotm/broken-out/userfaultfd-selftests-exercise-minor-fault-handling-shmem-support.patch
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next and is updated
there every 3-4 working days
------------------------------------------------------
From: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Subject: userfaultfd/selftests: exercise minor fault handling shmem support
Enable test_uffdio_minor for test_type == TEST_SHMEM, and modify the test
slightly to pass in / check for the right feature flags.
Link: https://lkml.kernel.org/r/20210503180737.2487560-11-axelrasmussen@xxxxxxxxxx
Signed-off-by: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Reviewed-by: Peter Xu <peterx@xxxxxxxxxx>
Cc: Alexander Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Brian Geffon <bgeffon@xxxxxxxxxx>
Cc: "Dr . David Alan Gilbert" <dgilbert@xxxxxxxxxx>
Cc: Hugh Dickins <hughd@xxxxxxxxxx>
Cc: Jerome Glisse <jglisse@xxxxxxxxxx>
Cc: Joe Perches <joe@xxxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill@xxxxxxxxxxxxx>
Cc: Lokesh Gidra <lokeshgidra@xxxxxxxxxx>
Cc: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxxxxxxx>
Cc: Mina Almasry <almasrymina@xxxxxxxxxx>
Cc: Oliver Upton <oupton@xxxxxxxxxx>
Cc: Shaohua Li <shli@xxxxxx>
Cc: Shuah Khan <shuah@xxxxxxxxxx>
Cc: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
Cc: Wang Qing <wangqing@xxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/vm/userfaultfd.c | 29 ++++++++++++++++++---
1 file changed, 25 insertions(+), 4 deletions(-)
--- a/tools/testing/selftests/vm/userfaultfd.c~userfaultfd-selftests-exercise-minor-fault-handling-shmem-support
+++ a/tools/testing/selftests/vm/userfaultfd.c
@@ -474,6 +474,7 @@ static void wp_range(int ufd, __u64 star
static void continue_range(int ufd, __u64 start, __u64 len)
{
struct uffdio_continue req;
+ int ret;
req.range.start = start;
req.range.len = len;
@@ -482,6 +483,17 @@ static void continue_range(int ufd, __u6
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)
@@ -1182,7 +1194,7 @@ 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;
@@ -1190,9 +1202,17 @@ static int userfaultfd_minor_test(void)
printf("testing minor faults: ");
fflush(stdout);
- uffd_test_ctx_init_ext(&features);
- /* If kernel reports the feature isn't supported, skip the test. */
- if (!(features & UFFD_FEATURE_MINOR_HUGETLBFS)) {
+ 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;
+ uffd_test_ctx_init_ext(&features_out);
+ /* 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;
@@ -1579,6 +1599,7 @@ static void set_test_type(const char *ty
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);
}
_
Patches currently in -mm which might be from axelrasmussen@xxxxxxxxxx are
userfaultfd-release-page-in-error-path-to-avoid-bug_on.patch
userfaultfd-hugetlbfs-avoid-including-userfaultfd_kh-in-hugetlbh.patch
userfaultfd-shmem-combine-shmem_mcopy_atomicmfill_zeropage_pte.patch
userfaultfd-shmem-support-minor-fault-registration-for-shmem.patch
userfaultfd-shmem-support-uffdio_continue-for-shmem.patch
userfaultfd-shmem-advertise-shmem-minor-fault-support.patch
userfaultfd-shmem-modify-shmem_mfill_atomic_pte-to-use-install_pte.patch
userfaultfd-selftests-use-memfd_create-for-shmem-test-type.patch
userfaultfd-selftests-create-alias-mappings-in-the-shmem-test.patch
userfaultfd-selftests-reinitialize-test-context-in-each-test.patch
userfaultfd-selftests-exercise-minor-fault-handling-shmem-support.patch
