diff --git a/lib/stackdepot.c b/lib/stackdepot.c index 4a7055a63d9f..c043a4186bc5 100644 --- a/lib/stackdepot.c +++ b/lib/stackdepot.c @@ -45,15 +45,16 @@ #define DEPOT_POOL_INDEX_BITS (DEPOT_HANDLE_BITS - DEPOT_OFFSET_BITS - \ STACK_DEPOT_EXTRA_BITS) #define DEPOT_POOLS_CAP 8192 +/* The pool_index is offset by 1 so the first record does not have a 0 handle. */ #define DEPOT_MAX_POOLS \ - (((1LL << (DEPOT_POOL_INDEX_BITS)) < DEPOT_POOLS_CAP) ? \ - (1LL << (DEPOT_POOL_INDEX_BITS)) : DEPOT_POOLS_CAP) + (((1LL << (DEPOT_POOL_INDEX_BITS)) - 1 < DEPOT_POOLS_CAP) ? \ + (1LL << (DEPOT_POOL_INDEX_BITS)) - 1 : DEPOT_POOLS_CAP) /* Compact structure that stores a reference to a stack. */ union handle_parts { depot_stack_handle_t handle; struct { - u32 pool_index : DEPOT_POOL_INDEX_BITS; + u32 pool_index : DEPOT_POOL_INDEX_BITS; /* pool_index is offset by 1 */ u32 offset : DEPOT_OFFSET_BITS; u32 extra : STACK_DEPOT_EXTRA_BITS; }; @@ -372,7 +373,7 @@ static struct stack_record *depot_pop_free_pool(void **prealloc, size_t size) stack = current_pool + pool_offset; /* Pre-initialize handle once. */ - stack->handle.pool_index = pool_index; + stack->handle.pool_index = pool_index + 1; stack->handle.offset = pool_offset >> DEPOT_STACK_ALIGN; stack->handle.extra = 0; INIT_LIST_HEAD(&stack->hash_list); @@ -483,18 +484,19 @@ static struct stack_record *depot_fetch_stack(depot_stack_handle_t handle) const int pools_num_cached = READ_ONCE(pools_num); union handle_parts parts = { .handle = handle }; void *pool; + u32 pool_index = parts.pool_index - 1; size_t offset = parts.offset << DEPOT_STACK_ALIGN; struct stack_record *stack; lockdep_assert_not_held(&pool_lock); - if (parts.pool_index > pools_num_cached) { + if (pool_index > pools_num_cached) { WARN(1, "pool index %d out of bounds (%d) for stack id %08x\n", - parts.pool_index, pools_num_cached, handle); + pool_index, pools_num_cached, handle); return NULL; } - pool = stack_pools[parts.pool_index]; + pool = stack_pools[pool_index]; if (WARN_ON(!pool)) return NULL;