The patch titled
Subject: selftests/vm: cow: R/O long-term pinning reliability tests for non-anon pages
has been added to the -mm mm-unstable branch. Its filename is
selftests-vm-cow-r-o-long-term-pinning-reliability-tests-for-non-anon-pages.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/selftests-vm-cow-r-o-long-term-pinning-reliability-tests-for-non-anon-pages.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: David Hildenbrand <david@xxxxxxxxxx>
Subject: selftests/vm: cow: R/O long-term pinning reliability tests for non-anon pages
Date: Wed, 16 Nov 2022 11:26:42 +0100
Let's test whether R/O long-term pinning is reliable for non-anonymous
memory: when R/O long-term pinning a page, the expectation is that we
break COW early before pinning, such that actual write access via the
page tables won't break COW later and end up replacing the R/O-pinned
page in the page table.
Consequently, R/O long-term pinning in private mappings would only target
exclusive anonymous pages.
For now, all tests fail:
# [RUN] R/O longterm GUP pin ... with shared zeropage
not ok 151 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP pin ... with memfd
not ok 152 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP pin ... with tmpfile
not ok 153 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP pin ... with huge zeropage
not ok 154 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP pin ... with memfd hugetlb (2048 kB)
not ok 155 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP pin ... with memfd hugetlb (1048576 kB)
not ok 156 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with shared zeropage
not ok 157 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with memfd
not ok 158 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with tmpfile
not ok 159 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with huge zeropage
not ok 160 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with memfd hugetlb (2048 kB)
not ok 161 Longterm R/O pin is reliable
# [RUN] R/O longterm GUP-fast pin ... with memfd hugetlb (1048576 kB)
not ok 162 Longterm R/O pin is reliable
Link: https://lkml.kernel.org/r/20221116102659.70287-4-david@xxxxxxxxxx
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
tools/testing/selftests/vm/cow.c | 28 +++++++++++++++++++++++++++-
1 file changed, 27 insertions(+), 1 deletion(-)
--- a/tools/testing/selftests/vm/cow.c~selftests-vm-cow-r-o-long-term-pinning-reliability-tests-for-non-anon-pages
+++ a/tools/testing/selftests/vm/cow.c
@@ -561,6 +561,7 @@ static void test_iouring_fork(char *mem,
#endif /* LOCAL_CONFIG_HAVE_LIBURING */
enum ro_pin_test {
+ RO_PIN_TEST,
RO_PIN_TEST_SHARED,
RO_PIN_TEST_PREVIOUSLY_SHARED,
RO_PIN_TEST_RO_EXCLUSIVE,
@@ -593,6 +594,8 @@ static void do_test_ro_pin(char *mem, si
}
switch (test) {
+ case RO_PIN_TEST:
+ break;
case RO_PIN_TEST_SHARED:
case RO_PIN_TEST_PREVIOUSLY_SHARED:
/*
@@ -1193,6 +1196,16 @@ static void test_cow(char *mem, const ch
free(old);
}
+static void test_ro_pin(char *mem, const char *smem, size_t size)
+{
+ do_test_ro_pin(mem, size, RO_PIN_TEST, false);
+}
+
+static void test_ro_fast_pin(char *mem, const char *smem, size_t size)
+{
+ do_test_ro_pin(mem, size, RO_PIN_TEST, true);
+}
+
static void run_with_zeropage(non_anon_test_fn fn, const char *desc)
{
char *mem, *smem, tmp;
@@ -1433,7 +1446,7 @@ struct non_anon_test_case {
};
/*
- * Test cases that target any pages in private mappings that are non anonymous:
+ * Test cases that target any pages in private mappings that are not anonymous:
* pages that may get shared via COW ndependent of fork(). This includes
* the shared zeropage(s), pagecache pages, ...
*/
@@ -1446,6 +1459,19 @@ static const struct non_anon_test_case n
"Basic COW",
test_cow,
},
+ /*
+ * Take a R/O longterm pin. When modifying the page via the page table,
+ * the page content change must be visible via the pin.
+ */
+ {
+ "R/O longterm GUP pin",
+ test_ro_pin,
+ },
+ /* Same as above, but using GUP-fast. */
+ {
+ "R/O longterm GUP-fast pin",
+ test_ro_fast_pin,
+ },
};
static void run_non_anon_test_case(struct non_anon_test_case const *test_case)
_
Patches currently in -mm which might be from david@xxxxxxxxxx are
selftests-vm-add-ksm-unmerge-tests.patch
mm-pagewalk-dont-trigger-test_walk-in-walk_page_vma.patch
selftests-vm-add-test-to-measure-madv_unmergeable-performance.patch
mm-ksm-simplify-break_ksm-to-not-rely-on-vm_fault_write.patch
mm-remove-vm_fault_write.patch
mm-ksm-fix-ksm-cow-breaking-with-userfaultfd-wp-via-fault_flag_unshare.patch
mm-pagewalk-add-walk_page_range_vma.patch
mm-ksm-convert-break_ksm-to-use-walk_page_range_vma.patch
mm-gup-remove-foll_migration.patch
mm-mprotect-minor-can_change_pte_writable-cleanups.patch
mm-huge_memory-try-avoiding-write-faults-when-changing-pmd-protection.patch
mm-mprotect-factor-out-check-whether-manual-pte-write-upgrades-are-required.patch
mm-autonuma-use-can_change_ptepmd_writable-to-replace-savedwrite.patch
mm-remove-unused-savedwrite-infrastructure.patch
selftests-vm-anon_cow-add-mprotect-optimization-tests.patch
selftests-vm-anon_cow-prepare-for-non-anonymous-cow-tests.patch
selftests-vm-cow-basic-cow-tests-for-non-anonymous-pages.patch
selftests-vm-cow-r-o-long-term-pinning-reliability-tests-for-non-anon-pages.patch
mm-add-early-fault_flag_unshare-consistency-checks.patch
mm-add-early-fault_flag_write-consistency-checks.patch
mm-rework-handling-in-do_wp_page-based-on-private-vs-shared-mappings.patch
mm-dont-call-vm_ops-huge_fault-in-wp_huge_pmd-wp_huge_pud-for-private-mappings.patch
mm-extend-fault_flag_unshare-support-to-anything-in-a-cow-mapping.patch
mm-gup-reliable-r-o-long-term-pinning-in-cow-mappings.patch
rdma-umem-remove-foll_force-usage.patch
rdma-usnic-remove-foll_force-usage.patch
rdma-siw-remove-foll_force-usage.patch
media-videobuf-dma-sg-remove-foll_force-usage.patch
drm-etnaviv-remove-foll_force-usage.patch
media-pci-ivtv-remove-foll_force-usage.patch
mm-frame-vector-remove-foll_force-usage.patch
drm-exynos-remove-foll_force-usage.patch
rdma-hw-qib-qib_user_pages-remove-foll_force-usage.patch
habanalabs-remove-foll_force-usage.patch
