2019-08-21 10:22:22

by Christophe Leroy

Subject: [PATCH] powerpc/8xx: set STACK_END_MAGIC earlier on the init_stack

Today, the STACK_END_MAGIC is set on init_stack in start_kernel().

To avoid a false 'Thread overran stack, or stack corrupted' message
on early Oopses, setup STACK_END_MAGIC as soon as possible.

Signed-off-by: Christophe Leroy <[email protected]>
---
arch/powerpc/kernel/head_8xx.S | 4 ++++
1 file changed, 4 insertions(+)

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 5ab9178c2347..b8ca5b43e587 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -15,6 +15,7 @@
*/

#include <linux/init.h>
+#include <linux/magic.h>
#include <asm/processor.h>
#include <asm/page.h>
#include <asm/mmu.h>
@@ -741,6 +742,9 @@ start_here:
/* stack */
lis r1,init_thread_union@ha
addi r1,r1,init_thread_union@l
+ lis r0, STACK_END_MAGIC@h
+ ori r0, r0, STACK_END_MAGIC@l
+ stw r0, 0(r1)
li r0,0
stwu r0,THREAD_SIZE-STACK_FRAME_OVERHEAD(r1)

--
2.13.3

2019-09-02 03:31:27

by Michael Ellerman

Subject: Re: [PATCH] powerpc/8xx: set STACK_END_MAGIC earlier on the init_stack

On Wed, 2019-08-21 at 10:20:51 UTC, Christophe Leroy wrote:
> Today, the STACK_END_MAGIC is set on init_stack in start_kernel().
>
> To avoid a false 'Thread overran stack, or stack corrupted' message
> on early Oopses, setup STACK_END_MAGIC as soon as possible.
>
> Signed-off-by: Christophe Leroy <[email protected]>

Applied to powerpc next, thanks.

https://git.kernel.org/powerpc/c/3bbd2343734e44de92238eea1a5cd3ad32a6baf0

cheers