lib/test_meminit.c: fix -Wmaybe-uninitialized false positive

The conditional logic is too complicated for the compiler to fully
comprehend:

  lib/test_meminit.c: In function 'test_meminit_init':
  lib/test_meminit.c:236:5: error: 'buf_copy' may be used uninitialized in this function [-Werror=maybe-uninitialized]
       kfree(buf_copy);
       ^~~~~~~~~~~~~~~
  lib/test_meminit.c:201:14: note: 'buf_copy' was declared here

Simplify it by splitting out the non-rcu section.

Link: http://lkml.kernel.org/r/20190617131210.2190280-1-arnd@arndb.de
Fixes: af734ee6ec85 ("lib: introduce test_meminit module")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/lib/test_meminit.c b/lib/test_meminit.c
index ed7efec1387b8a2ec1d7a6deac526828990477d9..7ae2183ff1f4be76ed039e140185d50c8ac9b918 100644 (file)
--- a/lib/test_meminit.c
+++ b/lib/test_meminit.c
@@ -208,35 +208,37 @@ static int __init do_kmem_cache_size(size_t size, bool want_ctor,
                /* Check that buf is zeroed, if it must be. */
                fail = check_buf(buf, size, want_ctor, want_rcu, want_zero);
                fill_with_garbage_skip(buf, size, want_ctor ? CTOR_BYTES : 0);
+
+               if (!want_rcu) {
+                       kmem_cache_free(c, buf);
+                       continue;
+               }
+
                /*
                 * If this is an RCU cache, use a critical section to ensure we
                 * can touch objects after they're freed.
                 */
-               if (want_rcu) {
-                       rcu_read_lock();
-                       /*
-                        * Copy the buffer to check that it's not wiped on
-                        * free().
-                        */
-                       buf_copy = kmalloc(size, GFP_KERNEL);
-                       if (buf_copy)
-                               memcpy(buf_copy, buf, size);
-               }
-               kmem_cache_free(c, buf);
-               if (want_rcu) {
-                       /*
-                        * Check that |buf| is intact after kmem_cache_free().
-                        * |want_zero| is false, because we wrote garbage to
-                        * the buffer already.
-                        */
-                       fail |= check_buf(buf, size, want_ctor, want_rcu,
-                                         false);
-                       if (buf_copy) {
-                               fail |= (bool)memcmp(buf, buf_copy, size);
-                               kfree(buf_copy);
-                       }
-                       rcu_read_unlock();
+               rcu_read_lock();
+               /*
+                * Copy the buffer to check that it's not wiped on
+                * free().
+                */
+               buf_copy = kmalloc(size, GFP_KERNEL);
+               if (buf_copy)
+                       memcpy(buf_copy, buf, size);
+
+               /*
+                * Check that |buf| is intact after kmem_cache_free().
+                * |want_zero| is false, because we wrote garbage to
+                * the buffer already.
+                */
+               fail |= check_buf(buf, size, want_ctor, want_rcu,
+                                 false);
+               if (buf_copy) {
+                       fail |= (bool)memcmp(buf, buf_copy, size);
+                       kfree(buf_copy);
                }
+               rcu_read_unlock();
        }
        kmem_cache_destroy(c);