lib/stackdepot: annotate init and early init functions
Add comments to stack_depot_early_init and stack_depot_init to explain certain parts of their implementation. Also add a pr_info message to stack_depot_early_init similar to the one in stack_depot_init. Also move the scale variable in stack_depot_init to the scope where it is being used. Link: https://lkml.kernel.org/r/d17fbfbd4d73f38686c5e3d4824a6d62047213a1.1676063693.git.andreyknvl@google.com Signed-off-by: Andrey Konovalov <andreyknvl@google.com> Reviewed-by: Alexander Potapenko <glider@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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@ -115,24 +115,34 @@ void __init stack_depot_request_early_init(void)
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__stack_depot_early_init_requested = true;
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__stack_depot_early_init_requested = true;
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}
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}
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/* Allocates a hash table via memblock. Can only be used during early boot. */
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int __init stack_depot_early_init(void)
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int __init stack_depot_early_init(void)
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{
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{
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unsigned long entries = 0;
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unsigned long entries = 0;
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/* This is supposed to be called only once, from mm_init() */
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/* This function must be called only once, from mm_init(). */
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if (WARN_ON(__stack_depot_early_init_passed))
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if (WARN_ON(__stack_depot_early_init_passed))
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return 0;
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return 0;
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__stack_depot_early_init_passed = true;
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__stack_depot_early_init_passed = true;
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/*
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* If KASAN is enabled, use the maximum order: KASAN is frequently used
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* in fuzzing scenarios, which leads to a large number of different
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* stack traces being stored in stack depot.
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*/
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if (kasan_enabled() && !stack_hash_order)
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if (kasan_enabled() && !stack_hash_order)
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stack_hash_order = STACK_HASH_ORDER_MAX;
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stack_hash_order = STACK_HASH_ORDER_MAX;
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if (!__stack_depot_early_init_requested || stack_depot_disabled)
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if (!__stack_depot_early_init_requested || stack_depot_disabled)
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return 0;
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return 0;
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/*
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* If stack_hash_order is not set, leave entries as 0 to rely on the
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* automatic calculations performed by alloc_large_system_hash.
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*/
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if (stack_hash_order)
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if (stack_hash_order)
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entries = 1UL << stack_hash_order;
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entries = 1UL << stack_hash_order;
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pr_info("allocating hash table via alloc_large_system_hash\n");
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stack_table = alloc_large_system_hash("stackdepot",
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stack_table = alloc_large_system_hash("stackdepot",
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sizeof(struct stack_record *),
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sizeof(struct stack_record *),
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entries,
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entries,
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@ -142,7 +152,6 @@ int __init stack_depot_early_init(void)
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&stack_hash_mask,
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&stack_hash_mask,
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1UL << STACK_HASH_ORDER_MIN,
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1UL << STACK_HASH_ORDER_MIN,
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1UL << STACK_HASH_ORDER_MAX);
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1UL << STACK_HASH_ORDER_MAX);
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if (!stack_table) {
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if (!stack_table) {
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pr_err("hash table allocation failed, disabling\n");
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pr_err("hash table allocation failed, disabling\n");
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stack_depot_disabled = true;
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stack_depot_disabled = true;
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@ -152,6 +161,7 @@ int __init stack_depot_early_init(void)
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return 0;
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return 0;
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}
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}
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/* Allocates a hash table via kvcalloc. Can be used after boot. */
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int stack_depot_init(void)
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int stack_depot_init(void)
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{
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{
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static DEFINE_MUTEX(stack_depot_init_mutex);
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static DEFINE_MUTEX(stack_depot_init_mutex);
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@ -160,11 +170,16 @@ int stack_depot_init(void)
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mutex_lock(&stack_depot_init_mutex);
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mutex_lock(&stack_depot_init_mutex);
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if (!stack_depot_disabled && !stack_table) {
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if (!stack_depot_disabled && !stack_table) {
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unsigned long entries;
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unsigned long entries;
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int scale = STACK_HASH_SCALE;
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/*
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* Similarly to stack_depot_early_init, use stack_hash_order
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* if assigned, and rely on automatic scaling otherwise.
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*/
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if (stack_hash_order) {
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if (stack_hash_order) {
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entries = 1UL << stack_hash_order;
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entries = 1UL << stack_hash_order;
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} else {
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} else {
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int scale = STACK_HASH_SCALE;
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entries = nr_free_buffer_pages();
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entries = nr_free_buffer_pages();
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entries = roundup_pow_of_two(entries);
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entries = roundup_pow_of_two(entries);
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@ -179,7 +194,7 @@ int stack_depot_init(void)
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if (entries > 1UL << STACK_HASH_ORDER_MAX)
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if (entries > 1UL << STACK_HASH_ORDER_MAX)
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entries = 1UL << STACK_HASH_ORDER_MAX;
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entries = 1UL << STACK_HASH_ORDER_MAX;
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pr_info("allocating hash table of %lu entries with kvcalloc\n",
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pr_info("allocating hash table of %lu entries via kvcalloc\n",
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entries);
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entries);
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stack_table = kvcalloc(entries, sizeof(struct stack_record *), GFP_KERNEL);
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stack_table = kvcalloc(entries, sizeof(struct stack_record *), GFP_KERNEL);
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if (!stack_table) {
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if (!stack_table) {
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