diff options
Diffstat (limited to 'mm/slab_common.c')
| -rw-r--r-- | mm/slab_common.c | 75 |
1 files changed, 75 insertions, 0 deletions
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, |