mm: Make mem_dump_obj() handle vmalloc() memory

This commit adds vmalloc() support to mem_dump_obj().  Note that the
vmalloc_dump_obj() function combines the checking and dumping, in
contrast with the split between kmem_valid_obj() and kmem_dump_obj().
The reason for the difference is that the checking in the vmalloc()
case involves acquiring a global lock, and redundant acquisitions of
global locks should be avoided, even on not-so-fast paths.

Note that this change causes on-stack variables to be reported as
vmalloc() storage from kernel_clone() or similar, depending on the degree
of inlining that your compiler does.  This is likely more helpful than
the earlier "non-paged (local) memory".

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: <linux-mm@kvack.org>
Reported-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Naresh Kamboju <naresh.kamboju@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>

1 files changed, 8 insertions, 6 deletions

diff --git a/mm/util.c b/mm/util.c
index 92f23d2c1277..54870226cea6 100644
--- a/mm/util.c
+++ b/mm/util.c
@@ -996,18 +996,20 @@ int __weak memcmp_pages(struct page *page1, struct page *page2)
  */
 void mem_dump_obj(void *object)
 {
+	if (kmem_valid_obj(object)) {
+		kmem_dump_obj(object);
+		return;
+	}
+	if (vmalloc_dump_obj(object))
+		return;
 	if (!virt_addr_valid(object)) {
 		if (object == NULL)
 			pr_cont(" NULL pointer.\n");
 		else if (object == ZERO_SIZE_PTR)
 			pr_cont(" zero-size pointer.\n");
 		else
-			pr_cont(" non-paged (local) memory.\n");
-		return;
-	}
-	if (kmem_valid_obj(object)) {
-		kmem_dump_obj(object);
+			pr_cont(" non-paged memory.\n");
 		return;
 	}
-	pr_cont(" non-slab memory.\n");
+	pr_cont(" non-slab/vmalloc memory.\n");
 }