On 2/1/22 14:29, Waiman Long wrote:
The gcc 12 compiler reports a warning on the following code:
static inline struct mem_section *__nr_to_section(unsigned long nr)
{
#ifdef CONFIG_SPARSEMEM_EXTREME
if (!mem_section)
return NULL;
#endif
:
With CONFIG_SPARSEMEM_EXTREME on, the mem_section definition is
extern struct mem_section **mem_section;
Obviously, mem_section cannot be NULL, but *mem_section can be if memory
hasn't been allocated for the dynamic mem_section[] array yet. Fix this
warning by checking for "!*mem_section" instead.
Fixes: 83e3c48729d9 ("mm/sparsemem: Allocate mem_section at runtime for CONFIG_SPARSEMEM_EXTREME=y")
Sorry, I forgot to add the line
Reported-by: Justin Forbes <jforbes@xxxxxxxxxx>
Signed-off-by: Waiman Long <longman@xxxxxxxxxx>
---
include/linux/mmzone.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index aed44e9b5d89..bd1b19925f3b 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -1390,7 +1390,7 @@ static inline unsigned long *section_to_usemap(struct mem_section *ms)
static inline struct mem_section *__nr_to_section(unsigned long nr)
{
#ifdef CONFIG_SPARSEMEM_EXTREME
- if (!mem_section)
+ if (!*mem_section)
return NULL;
#endif
if (!mem_section[SECTION_NR_TO_ROOT(nr)])
