From d18a90dd85f8243ed20cdadb6d8a37d595df456d Mon Sep 17 00:00:00 2001 From: Ben Greear Date: Thu, 7 Jul 2011 11:36:37 -0700 Subject: [PATCH] slub: Add method to verify memory is not freed This is for tracking down suspect memory usage. Acked-by: Christoph Lameter Signed-off-by: Ben Greear Signed-off-by: Pekka Enberg --- include/linux/slub_def.h | 13 +++++++++++++ mm/slub.c | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 49 insertions(+) diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h index fd4fdc72bc8c..4b35c06dfbc5 100644 --- a/include/linux/slub_def.h +++ b/include/linux/slub_def.h @@ -218,6 +218,19 @@ kmalloc_order(size_t size, gfp_t flags, unsigned int order) return ret; } +/** + * Calling this on allocated memory will check that the memory + * is expected to be in use, and print warnings if not. + */ +#ifdef CONFIG_SLUB_DEBUG +extern bool verify_mem_not_deleted(const void *x); +#else +static inline bool verify_mem_not_deleted(const void *x) +{ + return true; +} +#endif + #ifdef CONFIG_TRACING extern void * kmem_cache_alloc_trace(struct kmem_cache *s, gfp_t gfpflags, size_t size); diff --git a/mm/slub.c b/mm/slub.c index c9050995bc87..0e4f4f8245bc 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -2964,6 +2964,42 @@ size_t ksize(const void *object) } EXPORT_SYMBOL(ksize); +#ifdef CONFIG_SLUB_DEBUG +bool verify_mem_not_deleted(const void *x) +{ + struct page *page; + void *object = (void *)x; + unsigned long flags; + bool rv; + + if (unlikely(ZERO_OR_NULL_PTR(x))) + return false; + + local_irq_save(flags); + + page = virt_to_head_page(x); + if (unlikely(!PageSlab(page))) { + /* maybe it was from stack? */ + rv = true; + goto out_unlock; + } + + slab_lock(page); + if (on_freelist(page->slab, page, object)) { + object_err(page->slab, page, object, "Object is on free-list"); + rv = false; + } else { + rv = true; + } + slab_unlock(page); + +out_unlock: + local_irq_restore(flags); + return rv; +} +EXPORT_SYMBOL(verify_mem_not_deleted); +#endif + void kfree(const void *x) { struct page *page; -- 2.39.2