Hi Christophe,

Thanks for your reply.
It's my bad. According your reply, i read the code in sysfs_do_create_link_sd.There is a null pointer check indeed.

My intention was to check null pointer after memory allocation.
Whether we can add a comment here for someone like me, the null pointer check is no need here?


On 2023/11/24 23:17, Christophe Leroy wrote:

Le 22/11/2023 à 10:00, Kunwu Chan a écrit :
[Vous ne recevez pas souvent de courriers de chen...@kylinos.cn. Découvrez 
pourquoi ceci est important à https://aka.ms/LearnAboutSenderIdentification ]

kasprintf() returns a pointer to dynamically allocated memory
which can be NULL upon failure. Ensure the allocation was successful
by checking the pointer validity.

Are you sure this is needed ? Did you check what happens what name is NULL ?

If I followed stuff correctly, I end up in function
sysfs_do_create_link_sd() which already handles the NULL name case which
a big hammer warning.

Signed-off-by: Kunwu Chan <chen...@kylinos.cn>
   arch/powerpc/mm/init-common.c | 2 ++
   1 file changed, 2 insertions(+)

diff --git a/arch/powerpc/mm/init-common.c b/arch/powerpc/mm/init-common.c
index 119ef491f797..0884fc601c46 100644
--- a/arch/powerpc/mm/init-common.c
+++ b/arch/powerpc/mm/init-common.c
@@ -139,6 +139,8 @@ void pgtable_cache_add(unsigned int shift)

          align = max_t(unsigned long, align, minalign);
          name = kasprintf(GFP_KERNEL, "pgtable-2^%d", shift);
+       if (!name)
+               return;
          new = kmem_cache_create(name, table_size, align, 0, ctor(shift));
          if (!new)
                  panic("Could not allocate pgtable cache for order %d", shift);

Reply via email to