mm: kmemleak: disable early logging in case of error

If an error occurs during kmemleak_init() (e.g.  kmem cache cannot be
created), kmemleak is disabled but kmemleak_early_log remains enabled.
Subsequently, when the .init.text section is freed, the log_early()
function no longer exists.  To avoid a page fault in such scenario,
ensure that kmemleak_disable() also disables early logging.

Link: http://lkml.kernel.org/r/20190731152302.42073-1-catalin.marinas@arm.comSigned-off-by: Catalin Marinas <catalin.marinas@arm.com>
Reported-by: Qian Cai <cai@lca.pw>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/kmemleak.c

@@ -1966,6 +1966,7 @@ static void kmemleak_disable(void)
 
 	/* stop any memory operation tracing */
 	kmemleak_enabled = 0;
+	kmemleak_early_log = 0;
 
 	/* check whether it is too early for a kernel thread */
 	if (kmemleak_initialized)
@@ -2009,7 +2010,6 @@ void __init kmemleak_init(void)
 
 #ifdef CONFIG_DEBUG_KMEMLEAK_DEFAULT_OFF
 	if (!kmemleak_skip_disable) {
-		kmemleak_early_log = 0;
 		kmemleak_disable();
 		return;
 	}