From: Zhen Lei <[email protected]>
Commit 5bb1bb353cfe ("mm: Don't build mm_dump_obj() on CONFIG_PRINTK=n
kernels") only provides static inline empty function for mem_dump_obj().
But functions kmem_valid_obj() and kmem_dump_obj() are also exported,
they may be called by functions other than mem_dump_obj(), so their empty
functions should also be provided when CONFIG_PRINTK=n.
Signed-off-by: Zhen Lei <[email protected]>
---
include/linux/slab.h | 3 +++
1 file changed, 3 insertions(+)
diff --git a/include/linux/slab.h b/include/linux/slab.h
index 848c7c82ad5ad0b..fc05fe288d176b4 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -246,6 +246,9 @@ size_t ksize(const void *objp);
#ifdef CONFIG_PRINTK
bool kmem_valid_obj(void *object);
void kmem_dump_obj(void *object);
+#else
+static inline bool kmem_valid_obj(void *object) { return false; }
+static inline void kmem_dump_obj(void *object) {}
#endif
/*
--
2.34.1
On Wed, Aug 02, 2023 at 11:45:16AM +0800, [email protected] wrote:
> +++ b/include/linux/slab.h
> @@ -246,6 +246,9 @@ size_t ksize(const void *objp);
> #ifdef CONFIG_PRINTK
> bool kmem_valid_obj(void *object);
> void kmem_dump_obj(void *object);
> +#else
> +static inline bool kmem_valid_obj(void *object) { return false; }
That is very confusing. kmem_valid_obj() looks like a function which
should exist regardless of CONFIG_PRINTK and to have it always return
false if CONFIG_PRINTK isn't set seems weird.
I see we have one caller of kmem_valid_obj() right now. Which means it
shouldn't be an EXPORT_SYMBOL since that caller is not a module.
I think the right solution is to convert kmem_dump_obj() to
work the same way as vmalloc_dump_obj(). ie:
+++ b/mm/util.c
@@ -1057,11 +1057,8 @@ void mem_dump_obj(void *object)
{
const char *type;
- if (kmem_valid_obj(object)) {
- kmem_dump_obj(object);
+ if (kmem_dump_obj(object))
return;
- }
-
if (vmalloc_dump_obj(object))
return;
... with corresponding changes to eliminate kmem_valid_obj() as a
symbol.
On 2023/8/2 11:57, Matthew Wilcox wrote:
> On Wed, Aug 02, 2023 at 11:45:16AM +0800, [email protected] wrote:
>> +++ b/include/linux/slab.h
>> @@ -246,6 +246,9 @@ size_t ksize(const void *objp);
>> #ifdef CONFIG_PRINTK
>> bool kmem_valid_obj(void *object);
>> void kmem_dump_obj(void *object);
>> +#else
>> +static inline bool kmem_valid_obj(void *object) { return false; }
>
> That is very confusing. kmem_valid_obj() looks like a function which
> should exist regardless of CONFIG_PRINTK and to have it always return
> false if CONFIG_PRINTK isn't set seems weird.
Yes, I noticed it, but I didn't come up with a good idea.
>
> I see we have one caller of kmem_valid_obj() right now. Which means it
> shouldn't be an EXPORT_SYMBOL since that caller is not a module.
>
> I think the right solution is to convert kmem_dump_obj() to
> work the same way as vmalloc_dump_obj(). ie:
Okay, it's a good suggestion.
In fact, kmem_dump_obj() also does what kmem_valid_obj() does, except
that it will print warning if the check fails. So, do as you suggest,
the duplicated code can be eliminated.
>
> +++ b/mm/util.c
> @@ -1057,11 +1057,8 @@ void mem_dump_obj(void *object)
> {
> const char *type;
>
> - if (kmem_valid_obj(object)) {
> - kmem_dump_obj(object);
> + if (kmem_dump_obj(object))
> return;
> - }
> -
> if (vmalloc_dump_obj(object))
> return;
>
> ... with corresponding changes to eliminate kmem_valid_obj() as a
> symbol.
>
> .
>
--
Regards,
Zhen Lei