Merge tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Pull MM updates from Andrew Morton:
 "Many singleton patches against the MM code. The patch series which are
  included in this merge do the following:

   - Kemeng Shi has contributed some compation maintenance work in the
     series 'Fixes and cleanups to compaction'

   - Joel Fernandes has a patchset ('Optimize mremap during mutual
     alignment within PMD') which fixes an obscure issue with mremap()'s
     pagetable handling during a subsequent exec(), based upon an
     implementation which Linus suggested

   - More DAMON/DAMOS maintenance and feature work from SeongJae Park i
     the following patch series:

	mm/damon: misc fixups for documents, comments and its tracepoint
	mm/damon: add a tracepoint for damos apply target regions
	mm/damon: provide pseudo-moving sum based access rate
	mm/damon: implement DAMOS apply intervals
	mm/damon/core-test: Fix memory leaks in core-test
	mm/damon/sysfs-schemes: Do DAMOS tried regions update for only one apply interval

   - In the series 'Do not try to access unaccepted memory' Adrian
     Hunter provides some fixups for the recently-added 'unaccepted
     memory' feature. To increase the feature's checking coverage. 'Plug
     a few gaps where RAM is exposed without checking if it is
     unaccepted memory'

   - In the series 'cleanups for lockless slab shrink' Qi Zheng has done
     some maintenance work which is preparation for the lockless slab
     shrinking code

   - Qi Zheng has redone the earlier (and reverted) attempt to make slab
     shrinking lockless in the series 'use refcount+RCU method to
     implement lockless slab shrink'

   - David Hildenbrand contributes some maintenance work for the rmap
     code in the series 'Anon rmap cleanups'

   - Kefeng Wang does more folio conversions and some maintenance work
     in the migration code. Series 'mm: migrate: more folio conversion
     and unification'

   - Matthew Wilcox has fixed an issue in the buffer_head code which was
     causing long stalls under some heavy memory/IO loads. Some cleanups
     were added on the way. Series 'Add and use bdev_getblk()'

   - In the series 'Use nth_page() in place of direct struct page
     manipulation' Zi Yan has fixed a potential issue with the direct
     manipulation of hugetlb page frames

   - In the series 'mm: hugetlb: Skip initialization of gigantic tail
     struct pages if freed by HVO' has improved our handling of gigantic
     pages in the hugetlb vmmemmep optimizaton code. This provides
     significant boot time improvements when significant amounts of
     gigantic pages are in use

   - Matthew Wilcox has sent the series 'Small hugetlb cleanups' - code
     rationalization and folio conversions in the hugetlb code

   - Yin Fengwei has improved mlock()'s handling of large folios in the
     series 'support large folio for mlock'

   - In the series 'Expose swapcache stat for memcg v1' Liu Shixin has
     added statistics for memcg v1 users which are available (and
     useful) under memcg v2

   - Florent Revest has enhanced the MDWE (Memory-Deny-Write-Executable)
     prctl so that userspace may direct the kernel to not automatically
     propagate the denial to child processes. The series is named 'MDWE
     without inheritance'

   - Kefeng Wang has provided the series 'mm: convert numa balancing
     functions to use a folio' which does what it says

   - In the series 'mm/ksm: add fork-exec support for prctl' Stefan
     Roesch makes is possible for a process to propagate KSM treatment
     across exec()

   - Huang Ying has enhanced memory tiering's calculation of memory
     distances. This is used to permit the dax/kmem driver to use 'high
     bandwidth memory' in addition to Optane Data Center Persistent
     Memory Modules (DCPMM). The series is named 'memory tiering:
     calculate abstract distance based on ACPI HMAT'

   - In the series 'Smart scanning mode for KSM' Stefan Roesch has
     optimized KSM by teaching it to retain and use some historical
     information from previous scans

   - Yosry Ahmed has fixed some inconsistencies in memcg statistics in
     the series 'mm: memcg: fix tracking of pending stats updates
     values'

   - In the series 'Implement IOCTL to get and optionally clear info
     about PTEs' Peter Xu has added an ioctl to /proc/<pid>/pagemap
     which permits us to atomically read-then-clear page softdirty
     state. This is mainly used by CRIU

   - Hugh Dickins contributed the series 'shmem,tmpfs: general
     maintenance', a bunch of relatively minor maintenance tweaks to
     this code

   - Matthew Wilcox has increased the use of the VMA lock over
     file-backed page faults in the series 'Handle more faults under the
     VMA lock'. Some rationalizations of the fault path became possible
     as a result

   - In the series 'mm/rmap: convert page_move_anon_rmap() to
     folio_move_anon_rmap()' David Hildenbrand has implemented some
     cleanups and folio conversions

   - In the series 'various improvements to the GUP interface' Lorenzo
     Stoakes has simplified and improved the GUP interface with an eye
     to providing groundwork for future improvements

   - Andrey Konovalov has sent along the series 'kasan: assorted fixes
     and improvements' which does those things

   - Some page allocator maintenance work from Kemeng Shi in the series
     'Two minor cleanups to break_down_buddy_pages'

   - In thes series 'New selftest for mm' Breno Leitao has developed
     another MM self test which tickles a race we had between madvise()
     and page faults

   - In the series 'Add folio_end_read' Matthew Wilcox provides cleanups
     and an optimization to the core pagecache code

   - Nhat Pham has added memcg accounting for hugetlb memory in the
     series 'hugetlb memcg accounting'

   - Cleanups and rationalizations to the pagemap code from Lorenzo
     Stoakes, in the series 'Abstract vma_merge() and split_vma()'

   - Audra Mitchell has fixed issues in the procfs page_owner code's new
     timestamping feature which was causing some misbehaviours. In the
     series 'Fix page_owner's use of free timestamps'

   - Lorenzo Stoakes has fixed the handling of new mappings of sealed
     files in the series 'permit write-sealed memfd read-only shared
     mappings'

   - Mike Kravetz has optimized the hugetlb vmemmap optimization in the
     series 'Batch hugetlb vmemmap modification operations'

   - Some buffer_head folio conversions and cleanups from Matthew Wilcox
     in the series 'Finish the create_empty_buffers() transition'

   - As a page allocator performance optimization Huang Ying has added
     automatic tuning to the allocator's per-cpu-pages feature, in the
     series 'mm: PCP high auto-tuning'

   - Roman Gushchin has contributed the patchset 'mm: improve
     performance of accounted kernel memory allocations' which improves
     their performance by ~30% as measured by a micro-benchmark

   - folio conversions from Kefeng Wang in the series 'mm: convert page
     cpupid functions to folios'

   - Some kmemleak fixups in Liu Shixin's series 'Some bugfix about
     kmemleak'

   - Qi Zheng has improved our handling of memoryless nodes by keeping
     them off the allocation fallback list. This is done in the series
     'handle memoryless nodes more appropriately'

   - khugepaged conversions from Vishal Moola in the series 'Some
     khugepaged folio conversions'"

[ bcachefs conflicts with the dynamically allocated shrinkers have been
  resolved as per Stephen Rothwell in

     https://lore.kernel.org/all/20230913093553.4290421e@canb.auug.org.au/

  with help from Qi Zheng.

  The clone3 test filtering conflict was half-arsed by yours truly ]

* tag 'mm-stable-2023-11-01-14-33' of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm: (406 commits)
  mm/damon/sysfs: update monitoring target regions for online input commit
  mm/damon/sysfs: remove requested targets when online-commit inputs
  selftests: add a sanity check for zswap
  Documentation: maple_tree: fix word spelling error
  mm/vmalloc: fix the unchecked dereference warning in vread_iter()
  zswap: export compression failure stats
  Documentation: ubsan: drop "the" from article title
  mempolicy: migration attempt to match interleave nodes
  mempolicy: mmap_lock is not needed while migrating folios
  mempolicy: alloc_pages_mpol() for NUMA policy without vma
  mm: add page_rmappable_folio() wrapper
  mempolicy: remove confusing MPOL_MF_LAZY dead code
  mempolicy: mpol_shared_policy_init() without pseudo-vma
  mempolicy trivia: use pgoff_t in shared mempolicy tree
  mempolicy trivia: slightly more consistent naming
  mempolicy trivia: delete those ancient pr_debug()s
  mempolicy: fix migrate_pages(2) syscall return nr_failed
  kernfs: drop shared NUMA mempolicy hooks
  hugetlbfs: drop shared NUMA mempolicy pretence
  mm/damon/sysfs-test: add a unit test for damon_sysfs_set_targets()
  ...

1 files changed, 71 insertions, 38 deletions

diff --git a/mm/kmsan/kmsan_test.c b/mm/kmsan/kmsan_test.c
index 312989aa2865..07d3a3a5a9c5 100644
--- a/mm/kmsan/kmsan_test.c
+++ b/mm/kmsan/kmsan_test.c
@@ -67,6 +67,17 @@ static bool report_available(void)
 	return READ_ONCE(observed.available);
 }
 
+/* Reset observed.available, so that the test can trigger another report. */
+static void report_reset(void)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&observed.lock, flags);
+	WRITE_ONCE(observed.available, false);
+	observed.ignore = false;
+	spin_unlock_irqrestore(&observed.lock, flags);
+}
+
 /* Information we expect in a report. */
 struct expect_report {
 	const char *error_type; /* Error type. */
@@ -407,33 +418,25 @@ static void test_printk(struct kunit *test)
 	KUNIT_EXPECT_TRUE(test, report_matches(&expect));
 }
 
-/*
- * Prevent the compiler from optimizing @var away. Without this, Clang may
- * notice that @var is uninitialized and drop memcpy() calls that use it.
- *
- * There is OPTIMIZER_HIDE_VAR() in linux/compier.h that we cannot use here,
- * because it is implemented as inline assembly receiving @var as a parameter
- * and will enforce a KMSAN check. Same is true for e.g. barrier_data(var).
- */
-#define DO_NOT_OPTIMIZE(var) barrier()
+/* Prevent the compiler from inlining a memcpy() call. */
+static noinline void *memcpy_noinline(volatile void *dst,
+				      const volatile void *src, size_t size)
+{
+	return memcpy((void *)dst, (const void *)src, size);
+}
 
-/*
- * Test case: ensure that memcpy() correctly copies initialized values.
- * Also serves as a regression test to ensure DO_NOT_OPTIMIZE() does not cause
- * extra checks.
- */
+/* Test case: ensure that memcpy() correctly copies initialized values. */
 static void test_init_memcpy(struct kunit *test)
 {
 	EXPECTATION_NO_REPORT(expect);
-	volatile int src;
-	volatile int dst = 0;
+	volatile long long src;
+	volatile long long dst = 0;
 
-	DO_NOT_OPTIMIZE(src);
 	src = 1;
 	kunit_info(
 		test,
 		"memcpy()ing aligned initialized src to aligned dst (no reports)\n");
-	memcpy((void *)&dst, (void *)&src, sizeof(src));
+	memcpy_noinline((void *)&dst, (void *)&src, sizeof(src));
 	kmsan_check_memory((void *)&dst, sizeof(dst));
 	KUNIT_EXPECT_TRUE(test, report_matches(&expect));
 }
@@ -451,8 +454,7 @@ static void test_memcpy_aligned_to_aligned(struct kunit *test)
 	kunit_info(
 		test,
 		"memcpy()ing aligned uninit src to aligned dst (UMR report)\n");
-	DO_NOT_OPTIMIZE(uninit_src);
-	memcpy((void *)&dst, (void *)&uninit_src, sizeof(uninit_src));
+	memcpy_noinline((void *)&dst, (void *)&uninit_src, sizeof(uninit_src));
 	kmsan_check_memory((void *)&dst, sizeof(dst));
 	KUNIT_EXPECT_TRUE(test, report_matches(&expect));
 }
@@ -463,7 +465,7 @@ static void test_memcpy_aligned_to_aligned(struct kunit *test)
  *
  * Copying aligned 4-byte value to an unaligned one leads to touching two
  * aligned 4-byte values. This test case checks that KMSAN correctly reports an
- * error on the first of the two values.
+ * error on the mentioned two values.
  */
 static void test_memcpy_aligned_to_unaligned(struct kunit *test)
 {
@@ -474,33 +476,65 @@ static void test_memcpy_aligned_to_unaligned(struct kunit *test)
 	kunit_info(
 		test,
 		"memcpy()ing aligned uninit src to unaligned dst (UMR report)\n");
-	DO_NOT_OPTIMIZE(uninit_src);
-	memcpy((void *)&dst[1], (void *)&uninit_src, sizeof(uninit_src));
+	kmsan_check_memory((void *)&uninit_src, sizeof(uninit_src));
+	memcpy_noinline((void *)&dst[1], (void *)&uninit_src,
+			sizeof(uninit_src));
 	kmsan_check_memory((void *)dst, 4);
 	KUNIT_EXPECT_TRUE(test, report_matches(&expect));
+	report_reset();
+	kmsan_check_memory((void *)&dst[4], sizeof(uninit_src));
+	KUNIT_EXPECT_TRUE(test, report_matches(&expect));
 }
 
 /*
- * Test case: ensure that memcpy() correctly copies uninitialized values between
- * aligned `src` and unaligned `dst`.
+ * Test case: ensure that origin slots do not accidentally get overwritten with
+ * zeroes during memcpy().
  *
- * Copying aligned 4-byte value to an unaligned one leads to touching two
- * aligned 4-byte values. This test case checks that KMSAN correctly reports an
- * error on the second of the two values.
+ * Previously, when copying memory from an aligned buffer to an unaligned one,
+ * if there were zero origins corresponding to zero shadow values in the source
+ * buffer, they could have ended up being copied to nonzero shadow values in the
+ * destination buffer:
+ *
+ *  memcpy(0xffff888080a00000, 0xffff888080900002, 8)
+ *
+ *  src (0xffff888080900002): ..xx .... xx..
+ *  src origins:              o111 0000 o222
+ *  dst (0xffff888080a00000): xx.. ..xx
+ *  dst origins:              o111 0000
+ *                        (or 0000 o222)
+ *
+ * (here . stands for an initialized byte, and x for an uninitialized one.
+ *
+ * Ensure that this does not happen anymore, and for both destination bytes
+ * the origin is nonzero (i.e. KMSAN reports an error).
  */
-static void test_memcpy_aligned_to_unaligned2(struct kunit *test)
+static void test_memcpy_initialized_gap(struct kunit *test)
 {
-	EXPECTATION_UNINIT_VALUE_FN(expect,
-				    "test_memcpy_aligned_to_unaligned2");
-	volatile int uninit_src;
+	EXPECTATION_UNINIT_VALUE_FN(expect, "test_memcpy_initialized_gap");
+	volatile char uninit_src[12];
 	volatile char dst[8] = { 0 };
 
 	kunit_info(
 		test,
-		"memcpy()ing aligned uninit src to unaligned dst - part 2 (UMR report)\n");
-	DO_NOT_OPTIMIZE(uninit_src);
-	memcpy((void *)&dst[1], (void *)&uninit_src, sizeof(uninit_src));
-	kmsan_check_memory((void *)&dst[4], sizeof(uninit_src));
+		"unaligned 4-byte initialized value gets a nonzero origin after memcpy() - (2 UMR reports)\n");
+
+	uninit_src[0] = 42;
+	uninit_src[1] = 42;
+	uninit_src[4] = 42;
+	uninit_src[5] = 42;
+	uninit_src[6] = 42;
+	uninit_src[7] = 42;
+	uninit_src[10] = 42;
+	uninit_src[11] = 42;
+	memcpy_noinline((void *)&dst[0], (void *)&uninit_src[2], 8);
+
+	kmsan_check_memory((void *)&dst[0], 4);
+	KUNIT_EXPECT_TRUE(test, report_matches(&expect));
+	report_reset();
+	kmsan_check_memory((void *)&dst[2], 4);
+	KUNIT_EXPECT_FALSE(test, report_matches(&expect));
+	report_reset();
+	kmsan_check_memory((void *)&dst[4], 4);
 	KUNIT_EXPECT_TRUE(test, report_matches(&expect));
 }
 
@@ -513,7 +547,6 @@ static void test_memcpy_aligned_to_unaligned2(struct kunit *test)
                                                                             \
 		kunit_info(test,                                            \
 			   "memset" #size "() should initialize memory\n"); \
-		DO_NOT_OPTIMIZE(uninit);                                    \
 		memset##size((uint##size##_t *)&uninit, 0, 1);              \
 		kmsan_check_memory((void *)&uninit, sizeof(uninit));        \
 		KUNIT_EXPECT_TRUE(test, report_matches(&expect));           \
@@ -598,7 +631,7 @@ static struct kunit_case kmsan_test_cases[] = {
 	KUNIT_CASE(test_init_memcpy),
 	KUNIT_CASE(test_memcpy_aligned_to_aligned),
 	KUNIT_CASE(test_memcpy_aligned_to_unaligned),
-	KUNIT_CASE(test_memcpy_aligned_to_unaligned2),
+	KUNIT_CASE(test_memcpy_initialized_gap),
 	KUNIT_CASE(test_memset16),
 	KUNIT_CASE(test_memset32),
 	KUNIT_CASE(test_memset64),