diff options
| -rw-r--r-- | include/linux/mm.h | 2 | ||||
| -rw-r--r-- | include/linux/slab.h | 2 | ||||
| -rw-r--r-- | mm/slab.c | 20 | ||||
| -rw-r--r-- | mm/slab.h | 12 | ||||
| -rw-r--r-- | mm/slab_common.c | 75 | ||||
| -rw-r--r-- | mm/slob.c | 6 | ||||
| -rw-r--r-- | mm/slub.c | 40 | ||||
| -rw-r--r-- | mm/util.c | 24 |
8 files changed, 181 insertions, 0 deletions
diff --git a/include/linux/mm.h b/include/linux/mm.h index 5299b90a6c40..af7d050900e7 100644 --- a/include/linux/mm.h +++ b/include/linux/mm.h @@ -3169,5 +3169,7 @@ unsigned long wp_shared_mapping_range(struct address_space *mapping, extern int sysctl_nr_trim_pages; +void mem_dump_obj(void *object); + #endif /* __KERNEL__ */ #endif /* _LINUX_MM_H */ diff --git a/include/linux/slab.h b/include/linux/slab.h index be4ba5867ac5..7ae604076767 100644 --- a/include/linux/slab.h +++ b/include/linux/slab.h @@ -186,6 +186,8 @@ void kfree(const void *); void kfree_sensitive(const void *); size_t __ksize(const void *); size_t ksize(const void *); +bool kmem_valid_obj(void *object); +void kmem_dump_obj(void *object); #ifdef CONFIG_HAVE_HARDENED_USERCOPY_ALLOCATOR void __check_heap_object(const void *ptr, unsigned long n, struct page *page, diff --git a/mm/slab.c b/mm/slab.c index d7c8da9319c7..dcc55e78f353 100644 --- a/mm/slab.c +++ b/mm/slab.c @@ -3635,6 +3635,26 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t flags, EXPORT_SYMBOL(__kmalloc_node_track_caller); #endif /* CONFIG_NUMA */ +void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page) +{ + struct kmem_cache *cachep; + unsigned int objnr; + void *objp; + + kpp->kp_ptr = object; + kpp->kp_page = page; + cachep = page->slab_cache; + kpp->kp_slab_cache = cachep; + objp = object - obj_offset(cachep); + kpp->kp_data_offset = obj_offset(cachep); + page = virt_to_head_page(objp); + objnr = obj_to_index(cachep, page, objp); + objp = index_to_obj(cachep, page, objnr); + kpp->kp_objp = objp; + if (DEBUG && cachep->flags & SLAB_STORE_USER) + kpp->kp_ret = *dbg_userword(cachep, objp); +} + /** * __do_kmalloc - allocate memory * @size: how many bytes of memory are required. diff --git a/mm/slab.h b/mm/slab.h index 1a756a359fa8..ecad9b57bc44 100644 --- a/mm/slab.h +++ b/mm/slab.h @@ -615,4 +615,16 @@ static inline bool slab_want_init_on_free(struct kmem_cache *c) return false; } +#define KS_ADDRS_COUNT 16 +struct kmem_obj_info { + void *kp_ptr; + struct page *kp_page; + void *kp_objp; + unsigned long kp_data_offset; + struct kmem_cache *kp_slab_cache; + void *kp_ret; + void *kp_stack[KS_ADDRS_COUNT]; +}; +void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page); + #endif /* MM_SLAB_H */ diff --git a/mm/slab_common.c b/mm/slab_common.c index e981c80d216c..adbace4256ef 100644 --- a/mm/slab_common.c +++ b/mm/slab_common.c @@ -537,6 +537,81 @@ bool slab_is_available(void) return slab_state >= UP; } +/** + * kmem_valid_obj - does the pointer reference a valid slab object? + * @object: pointer to query. + * + * Return: %true if the pointer is to a not-yet-freed object from + * kmalloc() or kmem_cache_alloc(), either %true or %false if the pointer + * is to an already-freed object, and %false otherwise. + */ +bool kmem_valid_obj(void *object) +{ + struct page *page; + + /* Some arches consider ZERO_SIZE_PTR to be a valid address. */ + if (object < (void *)PAGE_SIZE || !virt_addr_valid(object)) + return false; + page = virt_to_head_page(object); + return PageSlab(page); +} + +/** + * kmem_dump_obj - Print available slab provenance information + * @object: slab object for which to find provenance information. + * + * This function uses pr_cont(), so that the caller is expected to have + * printed out whatever preamble is appropriate. The provenance information + * depends on the type of object and on how much debugging is enabled. + * For a slab-cache object, the fact that it is a slab object is printed, + * and, if available, the slab name, return address, and stack trace from + * the allocation of that object. + * + * This function will splat if passed a pointer to a non-slab object. + * If you are not sure what type of object you have, you should instead + * use mem_dump_obj(). + */ +void kmem_dump_obj(void *object) +{ + char *cp = IS_ENABLED(CONFIG_MMU) ? "" : "/vmalloc"; + int i; + struct page *page; + unsigned long ptroffset; + struct kmem_obj_info kp = { }; + + if (WARN_ON_ONCE(!virt_addr_valid(object))) + return; + page = virt_to_head_page(object); + if (WARN_ON_ONCE(!PageSlab(page))) { + pr_cont(" non-slab memory.\n"); + return; + } + kmem_obj_info(&kp, object, page); + if (kp.kp_slab_cache) + pr_cont(" slab%s %s", cp, kp.kp_slab_cache->name); + else + pr_cont(" slab%s", cp); + if (kp.kp_objp) + pr_cont(" start %px", kp.kp_objp); + if (kp.kp_data_offset) + pr_cont(" data offset %lu", kp.kp_data_offset); + if (kp.kp_objp) { + ptroffset = ((char *)object - (char *)kp.kp_objp) - kp.kp_data_offset; + pr_cont(" pointer offset %lu", ptroffset); + } + if (kp.kp_slab_cache && kp.kp_slab_cache->usersize) + pr_cont(" size %u", kp.kp_slab_cache->usersize); + if (kp.kp_ret) + pr_cont(" allocated at %pS\n", kp.kp_ret); + else + pr_cont("\n"); + for (i = 0; i < ARRAY_SIZE(kp.kp_stack); i++) { + if (!kp.kp_stack[i]) + break; + pr_info(" %pS\n", kp.kp_stack[i]); + } +} + #ifndef CONFIG_SLOB /* Create a cache during boot when no slab services are available yet */ void __init create_boot_cache(struct kmem_cache *s, const char *name, diff --git a/mm/slob.c b/mm/slob.c index 8d4bfa46247f..ef87ada8705d 100644 --- a/mm/slob.c +++ b/mm/slob.c @@ -461,6 +461,12 @@ out: spin_unlock_irqrestore(&slob_lock, flags); } +void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page) +{ + kpp->kp_ptr = object; + kpp->kp_page = page; +} + /* * End of slob allocator proper. Begin kmem_cache_alloc and kmalloc frontend. */ diff --git a/mm/slub.c b/mm/slub.c index 0c8b43a5b3b0..3c1a84316fd7 100644 --- a/mm/slub.c +++ b/mm/slub.c @@ -3919,6 +3919,46 @@ int __kmem_cache_shutdown(struct kmem_cache *s) return 0; } +void kmem_obj_info(struct kmem_obj_info *kpp, void *object, struct page *page) +{ + void *base; + int __maybe_unused i; + unsigned int objnr; + void *objp; + void *objp0; + struct kmem_cache *s = page->slab_cache; + struct track __maybe_unused *trackp; + + kpp->kp_ptr = object; + kpp->kp_page = page; + kpp->kp_slab_cache = s; + base = page_address(page); + objp0 = kasan_reset_tag(object); +#ifdef CONFIG_SLUB_DEBUG + objp = restore_red_left(s, objp0); +#else + objp = objp0; +#endif + objnr = obj_to_index(s, page, objp); + kpp->kp_data_offset = (unsigned long)((char *)objp0 - (char *)objp); + objp = base + s->size * objnr; + kpp->kp_objp = objp; + if (WARN_ON_ONCE(objp < base || objp >= base + page->objects * s->size || (objp - base) % s->size) || + !(s->flags & SLAB_STORE_USER)) + return; +#ifdef CONFIG_SLUB_DEBUG + trackp = get_track(s, objp, TRACK_ALLOC); + kpp->kp_ret = (void *)trackp->addr; +#ifdef CONFIG_STACKTRACE + for (i = 0; i < KS_ADDRS_COUNT && i < TRACK_ADDRS_COUNT; i++) { + kpp->kp_stack[i] = (void *)trackp->addrs[i]; + if (!kpp->kp_stack[i]) + break; + } +#endif +#endif +} + /******************************************************************** * Kmalloc subsystem *******************************************************************/ diff --git a/mm/util.c b/mm/util.c index 8c9b7d1e7c49..da46f9d6c382 100644 --- a/mm/util.c +++ b/mm/util.c @@ -982,3 +982,27 @@ int __weak memcmp_pages(struct page *page1, struct page *page2) kunmap_atomic(addr1); return ret; } + +/** + * mem_dump_obj - Print available provenance information + * @object: object for which to find provenance information. + * + * This function uses pr_cont(), so that the caller is expected to have + * printed out whatever preamble is appropriate. The provenance information + * depends on the type of object and on how much debugging is enabled. + * For example, for a slab-cache object, the slab name is printed, and, + * if available, the return address and stack trace from the allocation + * of that object. + */ +void mem_dump_obj(void *object) +{ + if (!virt_addr_valid(object)) { + pr_cont(" non-paged (local) memory.\n"); + return; + } + if (kmem_valid_obj(object)) { + kmem_dump_obj(object); + return; + } + pr_cont(" non-slab memory.\n"); +} |