diff options
| -rw-r--r-- | include/linux/stackdepot.h | 13 | ||||
| -rw-r--r-- | lib/stackdepot.c | 12 |
2 files changed, 20 insertions, 5 deletions
diff --git a/include/linux/stackdepot.h b/include/linux/stackdepot.h index 0b262e14144e..611716702d73 100644 --- a/include/linux/stackdepot.h +++ b/include/linux/stackdepot.h @@ -39,8 +39,9 @@ typedef u32 depot_flags_t; * to its declaration for more details. */ #define STACK_DEPOT_FLAG_CAN_ALLOC ((depot_flags_t)0x0001) +#define STACK_DEPOT_FLAG_GET ((depot_flags_t)0x0002) -#define STACK_DEPOT_FLAGS_NUM 1 +#define STACK_DEPOT_FLAGS_NUM 2 #define STACK_DEPOT_FLAGS_MASK ((depot_flags_t)((1 << STACK_DEPOT_FLAGS_NUM) - 1)) /* @@ -94,6 +95,9 @@ static inline int stack_depot_early_init(void) { return 0; } * flags of @alloc_flags). Otherwise, stack depot avoids any allocations and * fails if no space is left to store the stack trace. * + * If STACK_DEPOT_FLAG_GET is set in @depot_flags, stack depot will increment + * the refcount on the saved stack trace if it already exists in stack depot. + * * If the provided stack trace comes from the interrupt context, only the part * up to the interrupt entry is saved. * @@ -116,8 +120,11 @@ depot_stack_handle_t stack_depot_save_flags(unsigned long *entries, * @nr_entries: Number of frames in the stack * @alloc_flags: Allocation GFP flags * - * Context: Contexts where allocations via alloc_pages() are allowed. - * See stack_depot_save_flags() for more details. + * Does not increment the refcount on the saved stack trace; see + * stack_depot_save_flags() for more details. + * + * Context: Contexts where allocations via alloc_pages() are allowed; + * see stack_depot_save_flags() for more details. * * Return: Handle of the stack trace stored in depot, 0 on failure */ diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 59d61d5c09a7..911dee11bf39 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -23,6 +23,7 @@ #include <linux/mutex.h> #include <linux/percpu.h> #include <linux/printk.h> +#include <linux/refcount.h> #include <linux/slab.h> #include <linux/spinlock.h> #include <linux/stacktrace.h> @@ -60,6 +61,7 @@ struct stack_record { u32 hash; /* Hash in hash table */ u32 size; /* Number of stored frames */ union handle_parts handle; + refcount_t count; unsigned long entries[CONFIG_STACKDEPOT_MAX_FRAMES]; /* Frames */ }; @@ -373,6 +375,7 @@ depot_alloc_stack(unsigned long *entries, int size, u32 hash, void **prealloc) stack->hash = hash; stack->size = size; /* stack->handle is already filled in by depot_init_pool(). */ + refcount_set(&stack->count, 1); memcpy(stack->entries, entries, flex_array_size(stack, entries, size)); /* @@ -489,6 +492,8 @@ depot_stack_handle_t stack_depot_save_flags(unsigned long *entries, /* Fast path: look the stack trace up without full locking. */ found = find_stack(bucket, entries, nr_entries, hash); if (found) { + if (depot_flags & STACK_DEPOT_FLAG_GET) + refcount_inc(&found->count); read_unlock_irqrestore(&pool_rwlock, flags); goto exit; } @@ -528,12 +533,15 @@ depot_stack_handle_t stack_depot_save_flags(unsigned long *entries, list_add(&new->list, bucket); found = new; } - } else if (prealloc) { + } else { + if (depot_flags & STACK_DEPOT_FLAG_GET) + refcount_inc(&found->count); /* * Stack depot already contains this stack trace, but let's * keep the preallocated memory for future. */ - depot_keep_new_pool(&prealloc); + if (prealloc) + depot_keep_new_pool(&prealloc); } write_unlock_irqrestore(&pool_rwlock, flags); |