2018-09-14 07:06:52

by Sergei Trofimovich

Subject: [PATCH] ia64: disable SCHED_STACK_END_CHECK

SCHED_STACK_END_CHECK assumes stack grows in one direction.
ia64 is a rare case where it is not.

As a result kernel fails at startup as:
Kernel panic - not syncing: corrupted stack end detected inside scheduler

The error does not find a real problem: it's register backing store
is written on top of canary value.

Disable SCHED_STACK_END_CHECK on ia64 as there is no good
place for canary without moving initial stack address.

CC: Tony Luck <[email protected]>
CC: Fenghua Yu <[email protected]>
CC: [email protected]
CC: Andrew Morton <[email protected]>
CC: [email protected]
Signed-off-by: Sergei Trofimovich <[email protected]>
---
lib/Kconfig.debug | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 4966c4fbe7f7..a097dfe38d2b 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1004,7 +1004,7 @@ config SCHEDSTATS

config SCHED_STACK_END_CHECK
bool "Detect stack corruption on calls to schedule()"
- depends on DEBUG_KERNEL
+ depends on DEBUG_KERNEL && !IA64
default n
help
This option checks for a stack overrun on calls to schedule().
--
2.19.0

2018-10-15 19:16:44

by Sergei Trofimovich

Subject: Re: [PATCH] ia64: disable SCHED_STACK_END_CHECK

On Fri, 14 Sep 2018 08:06:17 +0100
Sergei Trofimovich <[email protected]> wrote:

> SCHED_STACK_END_CHECK assumes stack grows in one direction.
> ia64 is a rare case where it is not.
>
> As a result kernel fails at startup as:
> Kernel panic - not syncing: corrupted stack end detected inside scheduler
>
> The error does not find a real problem: it's register backing store
> is written on top of canary value.
>
> Disable SCHED_STACK_END_CHECK on ia64 as there is no good
> place for canary without moving initial stack address.
>
> CC: Tony Luck <[email protected]>
> CC: Fenghua Yu <[email protected]>
> CC: [email protected]
> CC: Andrew Morton <[email protected]>
> CC: [email protected]
> Signed-off-by: Sergei Trofimovich <[email protected]>
> ---
> lib/Kconfig.debug | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
> index 4966c4fbe7f7..a097dfe38d2b 100644
> --- a/lib/Kconfig.debug
> +++ b/lib/Kconfig.debug
> @@ -1004,7 +1004,7 @@ config SCHEDSTATS
>
> config SCHED_STACK_END_CHECK
> bool "Detect stack corruption on calls to schedule()"
> - depends on DEBUG_KERNEL
> + depends on DEBUG_KERNEL && !IA64
> default n
> help
> This option checks for a stack overrun on calls to schedule().
> --
> 2.19.0
>

Ping.

--

Sergei