Merge tag 'slab-for-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

Pull slab updates from Vlastimil Babka:

 - Conversion of slub_debug stack traces to stackdepot, allowing more
   useful debugfs-based inspection for e.g. memory leak debugging.
   Allocation and free debugfs info now includes full traces and is
   sorted by the unique trace frequency.

   The stackdepot conversion was already attempted last year but
   reverted by ae14c63a9f20. The memory overhead (while not actually
   enabled on boot) has been meanwhile solved by making the large
   stackdepot allocation dynamic. The xfstest issues haven't been
   reproduced on current kernel locally nor in -next, so the slab cache
   layout changes that originally made that bug manifest were probably
   not the root cause.

 - Refactoring of dma-kmalloc caches creation.

 - Trivial cleanups such as removal of unused parameters, fixes and
   clarifications of comments.

 - Hyeonggon Yoo joins as a reviewer.

* tag 'slab-for-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab:
  MAINTAINERS: add myself as reviewer for slab
  mm/slub: remove unused kmem_cache_order_objects max
  mm: slab: fix comment for __assume_kmalloc_alignment
  mm: slab: fix comment for ARCH_KMALLOC_MINALIGN
  mm/slub: remove unneeded return value of slab_pad_check
  mm/slab_common: move dma-kmalloc caches creation into new_kmalloc_cache()
  mm/slub: remove meaningless node check in ___slab_alloc()
  mm/slub: remove duplicate flag in allocate_slab()
  mm/slub: remove unused parameter in setup_object*()
  mm/slab.c: fix comments
  slab, documentation: add description of debugfs files for SLUB caches
  mm/slub: sort debugfs output by frequency of stack traces
  mm/slub: distinguish and print stack traces in debugfs files
  mm/slub: use stackdepot to save stack trace in objects
  mm/slub: move struct track init out of set_track()
  lib/stackdepot: allow requesting early initialization dynamically
  mm/slub, kunit: Make slub_kunit unaffected by user specified flags
  mm/slab: remove some unused functions

3 files changed, 51 insertions, 27 deletions

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index a30d5279efda..388fb808ff18 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -710,6 +710,7 @@ config DEBUG_SLAB
 config SLUB_DEBUG_ON
 	bool "SLUB debugging on by default"
 	depends on SLUB && SLUB_DEBUG
+	select STACKDEPOT_ALWAYS_INIT if STACKTRACE_SUPPORT
 	default n
 	help
 	  Boot with debugging on by default. SLUB boots by default with
diff --git a/lib/slub_kunit.c b/lib/slub_kunit.c
index 8662dc6cb509..7a0564d7cb7a 100644
--- a/lib/slub_kunit.c
+++ b/lib/slub_kunit.c
@@ -12,7 +12,7 @@ static int slab_errors;
 static void test_clobber_zone(struct kunit *test)
 {
 	struct kmem_cache *s = kmem_cache_create("TestSlub_RZ_alloc", 64, 0,
-				SLAB_RED_ZONE, NULL);
+				SLAB_RED_ZONE|SLAB_NO_USER_FLAGS, NULL);
 	u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
 
 	kasan_disable_current();
@@ -30,7 +30,7 @@ static void test_clobber_zone(struct kunit *test)
 static void test_next_pointer(struct kunit *test)
 {
 	struct kmem_cache *s = kmem_cache_create("TestSlub_next_ptr_free", 64, 0,
-				SLAB_POISON, NULL);
+				SLAB_POISON|SLAB_NO_USER_FLAGS, NULL);
 	u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
 	unsigned long tmp;
 	unsigned long *ptr_addr;
@@ -75,7 +75,7 @@ static void test_next_pointer(struct kunit *test)
 static void test_first_word(struct kunit *test)
 {
 	struct kmem_cache *s = kmem_cache_create("TestSlub_1th_word_free", 64, 0,
-				SLAB_POISON, NULL);
+				SLAB_POISON|SLAB_NO_USER_FLAGS, NULL);
 	u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
 
 	kmem_cache_free(s, p);
@@ -90,7 +90,7 @@ static void test_first_word(struct kunit *test)
 static void test_clobber_50th_byte(struct kunit *test)
 {
 	struct kmem_cache *s = kmem_cache_create("TestSlub_50th_word_free", 64, 0,
-				SLAB_POISON, NULL);
+				SLAB_POISON|SLAB_NO_USER_FLAGS, NULL);
 	u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
 
 	kmem_cache_free(s, p);
@@ -106,7 +106,7 @@ static void test_clobber_50th_byte(struct kunit *test)
 static void test_clobber_redzone_free(struct kunit *test)
 {
 	struct kmem_cache *s = kmem_cache_create("TestSlub_RZ_free", 64, 0,
-				SLAB_RED_ZONE, NULL);
+				SLAB_RED_ZONE|SLAB_NO_USER_FLAGS, NULL);
 	u8 *p = kmem_cache_alloc(s, GFP_KERNEL);
 
 	kasan_disable_current();
diff --git a/lib/stackdepot.c b/lib/stackdepot.c
index bf5ba9af0500..5ca0d086ef4a 100644
--- a/lib/stackdepot.c
+++ b/lib/stackdepot.c
@@ -66,6 +66,9 @@ struct stack_record {
 	unsigned long entries[];	/* Variable-sized array of entries. */
 };
 
+static bool __stack_depot_want_early_init __initdata = IS_ENABLED(CONFIG_STACKDEPOT_ALWAYS_INIT);
+static bool __stack_depot_early_init_passed __initdata;
+
 static void *stack_slabs[STACK_ALLOC_MAX_SLABS];
 
 static int depot_index;
@@ -162,38 +165,58 @@ static int __init is_stack_depot_disabled(char *str)
 }
 early_param("stack_depot_disable", is_stack_depot_disabled);
 
-/*
- * __ref because of memblock_alloc(), which will not be actually called after
- * the __init code is gone, because at that point slab_is_available() is true
- */
-__ref int stack_depot_init(void)
+void __init stack_depot_want_early_init(void)
+{
+	/* Too late to request early init now */
+	WARN_ON(__stack_depot_early_init_passed);
+
+	__stack_depot_want_early_init = true;
+}
+
+int __init stack_depot_early_init(void)
+{
+	size_t size;
+
+	/* This is supposed to be called only once, from mm_init() */
+	if (WARN_ON(__stack_depot_early_init_passed))
+		return 0;
+
+	__stack_depot_early_init_passed = true;
+
+	if (!__stack_depot_want_early_init || stack_depot_disable)
+		return 0;
+
+	size = (STACK_HASH_SIZE * sizeof(struct stack_record *));
+	pr_info("Stack Depot early init allocating hash table with memblock_alloc, %zu bytes\n",
+		size);
+	stack_table = memblock_alloc(size, SMP_CACHE_BYTES);
+
+	if (!stack_table) {
+		pr_err("Stack Depot hash table allocation failed, disabling\n");
+		stack_depot_disable = true;
+		return -ENOMEM;
+	}
+
+	return 0;
+}
+
+int stack_depot_init(void)
 {
 	static DEFINE_MUTEX(stack_depot_init_mutex);
+	int ret = 0;
 
 	mutex_lock(&stack_depot_init_mutex);
 	if (!stack_depot_disable && !stack_table) {
-		size_t size = (STACK_HASH_SIZE * sizeof(struct stack_record *));
-		int i;
-
-		if (slab_is_available()) {
-			pr_info("Stack Depot allocating hash table with kvmalloc\n");
-			stack_table = kvmalloc(size, GFP_KERNEL);
-		} else {
-			pr_info("Stack Depot allocating hash table with memblock_alloc\n");
-			stack_table = memblock_alloc(size, SMP_CACHE_BYTES);
-		}
-		if (stack_table) {
-			for (i = 0; i < STACK_HASH_SIZE;  i++)
-				stack_table[i] = NULL;
-		} else {
+		pr_info("Stack Depot allocating hash table with kvcalloc\n");
+		stack_table = kvcalloc(STACK_HASH_SIZE, sizeof(struct stack_record *), GFP_KERNEL);
+		if (!stack_table) {
 			pr_err("Stack Depot hash table allocation failed, disabling\n");
 			stack_depot_disable = true;
-			mutex_unlock(&stack_depot_init_mutex);
-			return -ENOMEM;
+			ret = -ENOMEM;
 		}
 	}
 	mutex_unlock(&stack_depot_init_mutex);
-	return 0;
+	return ret;
 }
 EXPORT_SYMBOL_GPL(stack_depot_init);