kmemleak: Annotate false positive in init_section_page_cgroup()

The pointer to the page_cgroup table allocated in init_section_page_cgroup() is stored in section->page_cgroup as (base - pfn). Since this value does not point to the beginning or inside the allocated memory block, kmemleak reports a false positive. This was reported in bugzilla.kernel.org as #16297. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Reported-by: Adrien Dessemond <adrien.dessemond@gmail.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Andrew Morton <akpm@linux-foundation.org>

kmemleak: Annotate false positive in init_section_page_cgroup()
The pointer to the page_cgroup table allocated in init_section_page_cgroup() is stored in section->page_cgroup as (base - pfn). Since this value does not point to the beginning or inside the allocated memory block, kmemleak reports a false positive. This was reported in bugzilla.kernel.org as #16297. Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Reported-by: Adrien Dessemond <adrien.dessemond@gmail.com> Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com> Cc: Pekka Enberg <penberg@cs.helsinki.fi> Cc: Andrew Morton <akpm@linux-foundation.org>
Catalin Marinas
1 parent 815c4163b6
Showing 1 changed file with 7 additions and 0 deletions Side-by-side Diff
mm/page_cgroup.c
@@ -9,6 +9,7 @@
 #include <linux/vmalloc.h>
 #include <linux/cgroup.h>
 #include <linux/swapops.h>
+#include <linux/kmemleak.h>
  
 static void __meminit
 __init_page_cgroup(struct page_cgroup *pc, unsigned long pfn)
@@ -126,6 +127,12 @@
 			if (!base)
 				base = vmalloc(table_size);
 		}
+		/*
+		 * The value stored in section->page_cgroup is (base - pfn)
+		 * and it does not point to the memory block allocated above,
+		 * causing kmemleak false positives.
+		 */
+		kmemleak_not_leak(base);
 	} else {
 		/*
  		 * We don't have to allocate page_cgroup again, but
...	...	@@ -9,6 +9,7 @@
9	9	#include <linux/vmalloc.h>
10	10	#include <linux/cgroup.h>
11	11	#include <linux/swapops.h>
	12	+#include <linux/kmemleak.h>
12	13
13	14	static void __meminit
14	15	__init_page_cgroup(struct page_cgroup *pc, unsigned long pfn)
...	...	@@ -126,6 +127,12 @@
126	127	if (!base)
127	128	base = vmalloc(table_size);
128	129	}
	130	+ /*
	131	+ * The value stored in section->page_cgroup is (base - pfn)
	132	+ * and it does not point to the memory block allocated above,
	133	+ * causing kmemleak false positives.
	134	+ */
	135	+ kmemleak_not_leak(base);
129	136	} else {
130	137	/*
131	138	* We don't have to allocate page_cgroup again, but