2020-11-06 03:33:07

by h00486469

Subject: [PATCH] x86/kexec: Initialize the value of ident mapping offset

From: hewenliang <[email protected]>

It is necessary to initialize the value of ident mapping offset.
This can not only avoid using dirty data, but also improve the
code readability when we using the variable of offset.

Signed-off-by: hewenliang <[email protected]>
---
arch/x86/kernel/machine_kexec_64.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/arch/x86/kernel/machine_kexec_64.c b/arch/x86/kernel/machine_kexec_64.c
index a29a44a98e5b..101cbce893e4 100644
--- a/arch/x86/kernel/machine_kexec_64.c
+++ b/arch/x86/kernel/machine_kexec_64.c
@@ -196,6 +196,7 @@ static int init_pgtable(struct kimage *image, unsigned long start_pgtable)
.alloc_pgt_page = alloc_pgt_page,
.context = image,
.page_flag = __PAGE_KERNEL_LARGE_EXEC,
+ .offset = 0,
.kernpg_flag = _KERNPG_TABLE_NOENC,
};
unsigned long mstart, mend;
--
2.19.1

2020-11-06 15:25:30

by Borislav Petkov

Subject: Re: [PATCH] x86/kexec: Initialize the value of ident mapping offset

On Thu, Nov 05, 2020 at 10:30:05PM -0500, Hewenliang wrote:
> From: hewenliang <[email protected]>
>
> It is necessary to initialize the value of ident mapping offset.

Why is it necessary?

> This can not only avoid using dirty data,

What happens to designated initializers when some of the members are not
explicitly mentioned?

Hint:

$ make arch/x86/kernel/machine_kexec_64.s

and look at that file before your patch.

--
Regards/Gruss,
Boris.

https://people.kernel.org/tglx/notes-about-netiquette