Re: [PATCH 06/12] x86: efi: Replace GFP_ATOMIC with GFP_KERNEL in efi_query_variable_store

From: Ingo Molnar
Date: Fri Mar 09 2018 - 02:54:47 EST



* Ard Biesheuvel <ard.biesheuvel@xxxxxxxxxx> wrote:

> From: Jia-Ju Bai <baijiaju1990@xxxxxxxxx>
>
> The function kzalloc here is not called in atomic context.
> If nonblocking in efi_query_variable_store is true,
> namely it is in atomic context, efi_query_variable_store will return before
> this kzalloc is called.
> Thus GFP_ATOMIC is not necessary, and it can be replaced with GFP_KERNEL.
>
> This is found by a static analysis tool named DCNS written by myself.

Please fix typos/spelling in changelogs when applying patches.

I improved the above to:

efi_query_variable_store() does an atomic kzalloc() unnecessarily,
because we can never get this far when called in an atomic context,
namely when nonblocking == 1.

Replace it with GFP_KERNEL.

This was found by the DCNS static analysis tool written by myself.

Thanks,

Ingo