Re: [PATCH 1/2] loongarch/vdso: add missing NULL check after kcalloc()

["Jackie Liu" <liu.yun@linux.dev>]

2025年9月18日 15:17, "Huacai Chen" <chenhuacai@kernel.org mailto:chenhuacai@kernel.org?to=%22Huacai%20Chen%22%20%3Cchenhuacai%40kernel.org%3E > 写到:

Hi Huacai

> 
> Hi, Jackie,
> 
> Someone has already sent a patch and be applied, don't you know?
> 
> https://lore.kernel.org/loongarch/CAAhV-H6hTFrUO5gTx6FYo89TAouEykTvKpLNkqFfhtsg0PVLiw@mail.gmail.com/T/#t
> 
> Huacai

Ah, I just checked Linus's tree, While looking into other
memory allocation failures, I took the chance to try fixing this as well. Thanks
for pointing it out.

--- 
Jackie Liu

> 
> On Thu, Sep 18, 2025 at 2:45 PM Jackie Liu <liu.yun@linux.dev> wrote:
> 
> > 
> > From: Jackie Liu <liuyun01@kylinos.cn>
> > 
> >  The kcalloc() call in init_vdso() allocates memory for code_mapping.pages,
> >  but its return value was not validated before use. This could cause
> >  NULL pointer dereference if allocation fails.
> > 
> >  Add a check for the kcalloc() result and return -ENOMEM on failure.
> > 
> >  Signed-off-by: Jackie Liu <liuyun01@kylinos.cn>
> >  ---
> >  arch/loongarch/kernel/vdso.c | 2 ++
> >  1 file changed, 2 insertions(+)
> > 
> >  diff --git a/arch/loongarch/kernel/vdso.c b/arch/loongarch/kernel/vdso.c
> >  index 7b888d9085a0..088f8095210b 100644
> >  --- a/arch/loongarch/kernel/vdso.c
> >  +++ b/arch/loongarch/kernel/vdso.c
> >  @@ -53,6 +53,8 @@ static int __init init_vdso(void)
> >  vdso_info.size = PAGE_ALIGN(vdso_end - vdso_start);
> >  vdso_info.code_mapping.pages =
> >  kcalloc(vdso_info.size / PAGE_SIZE, sizeof(struct page *), GFP_KERNEL);
> >  + if (!vdso_info.code_mapping.pages)
> >  + return -ENOMEM;
> > 
> >  pfn = __phys_to_pfn(__pa_symbol(vdso_info.vdso));
> >  for (i = 0; i < vdso_info.size / PAGE_SIZE; i++)
> >  --
> >  2.51.0
> >
>