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

Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
---
v2: Use "panic" instead of "return"
---
 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..9788950b33f5 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)
+		panic("Failed to allocate memory for order %d", shift);
 	new = kmem_cache_create(name, table_size, align, 0, ctor(shift));
 	if (!new)
 		panic("Could not allocate pgtable cache for order %d", shift);
-- 
2.34.1

Kunwu Chan <chentao@kylinos.cn> writes:
> kasprintf() returns a pointer to dynamically allocated memory
> which can be NULL upon failure. Ensure the allocation was successful
> by checking the pointer validity.
>
> Suggested-by: Christophe Leroy <christophe.leroy@csgroup.eu>
> Suggested-by: Michael Ellerman <mpe@ellerman.id.au>
> Signed-off-by: Kunwu Chan <chentao@kylinos.cn>
> ---
> v2: Use "panic" instead of "return"
> ---
>  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..9788950b33f5 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)
> +		panic("Failed to allocate memory for order %d", shift);
>  	new = kmem_cache_create(name, table_size, align, 0, ctor(shift));
>  	if (!new)
>  		panic("Could not allocate pgtable cache for order %d", shift);

It would be nice to avoid two calls to panic. Can you reorganise the
logic so that there's only one? Initialising new to NULL might help.

cheers

Sure,i'll follow your suggestion in v3 patch:
1. set new to NULL
2. add a 'if' judgment before 'kmem_cache_create'

Thanks,
Kunwu

On 2023/12/1 18:17, Michael Ellerman wrote:
> avoid two calls to panic