Merge tag 'integrity-v5.12' of git://git.kernel.org/pub/scm/linux/kernel/git/zohar...

[linux-2.6-microblaze.git] / mm / slab_common.c

diff --git a/mm/slab_common.c b/mm/slab_common.c
index e981c80..adbace4 100644 (file)
--- 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,