2010-08-26 13:16:42

by Adam Jiang

[permalink] [raw]
Subject: [PATCH] mips: irq: add stackoverflow detection

Add stackoverflow detection to mips arch
---
arch/mips/Kconfig.debug | 7 +++++++
arch/mips/kernel/irq.c | 19 +++++++++++++++++++
2 files changed, 26 insertions(+), 0 deletions(-)

diff --git a/arch/mips/Kconfig.debug b/arch/mips/Kconfig.debug
index 43dc279..f1a00a2 100644
--- a/arch/mips/Kconfig.debug
+++ b/arch/mips/Kconfig.debug
@@ -67,6 +67,13 @@ config CMDLINE_OVERRIDE

Normally, you will choose 'N' here.

+config DEBUG_STACKOVERFLOW
+ bool "Check for stack overflows"
+ depends on DEBUG_KERNEL
+ help
+ This option will cause messages to be printed if free stack space
+ drops below a certain limit.
+
config DEBUG_STACK_USAGE
bool "Enable stack utilization instrumentation"
depends on DEBUG_KERNEL
diff --git a/arch/mips/kernel/irq.c b/arch/mips/kernel/irq.c
index c6345f5..8fdf79e 100644
--- a/arch/mips/kernel/irq.c
+++ b/arch/mips/kernel/irq.c
@@ -151,6 +151,25 @@ void __init init_IRQ(void)
#endif
}

+#ifdef DEBUG_STACKOVERFLOW
+static inline void check_stack_overflow(void)
+{
+ long sp;
+
+ asm volatile("move %0, $sp" : "=r" (sp));
+ sp = sp & (THREAD_SIZE-1);
+
+ /* check for stack overflow: is there less than 2KB free? */
+ if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
+ printk("do_IRQ: stack overflow: %ld\n",
+ sp - sizeof(struct thread_info));
+ dump_stack();
+ }
+}
+#else
+static inline void check_stack_overflow(void) {}
+#endif
+
/*
* do_IRQ handles all normal device IRQ's (the special
* SMP cross-CPU interrupts have their own specific
--
1.7.1


2010-08-26 19:01:41

by Sergei Shtylyov

[permalink] [raw]
Subject: Re: [PATCH] mips: irq: add stackoverflow detection

Hello.

Adam Jiang wrote:

> Add stackoverflow detection to mips arch

[...]

> diff --git a/arch/mips/kernel/irq.c b/arch/mips/kernel/irq.c
> index c6345f5..8fdf79e 100644
> --- a/arch/mips/kernel/irq.c
> +++ b/arch/mips/kernel/irq.c
> @@ -151,6 +151,25 @@ void __init init_IRQ(void)
> #endif
> }
>
> +#ifdef DEBUG_STACKOVERFLOW
> +static inline void check_stack_overflow(void)
> +{
> + long sp;
> +
> + asm volatile("move %0, $sp" : "=r" (sp));
> + sp = sp & (THREAD_SIZE-1);
> +
> + /* check for stack overflow: is there less than 2KB free? */
> + if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
> + printk("do_IRQ: stack overflow: %ld\n",
> + sp - sizeof(struct thread_info));
> + dump_stack();
> + }
> +}
> +#else
> +static inline void check_stack_overflow(void) {}
> +#endif
> +
> /*
> * do_IRQ handles all normal device IRQ's (the special
> * SMP cross-CPU interrupts have their own specific

You've dropped call check_stack_overflow() call in do_IRQ() -- was that
intentional?

WBR, Sergei

2010-08-26 23:27:47

by Adam Jiang

[permalink] [raw]
Subject: Re: [PATCH] mips: irq: add stackoverflow detection

On Thu, Aug 26, 2010 at 11:00:49PM +0400, Sergei Shtylyov wrote:
> Hello.
>
> Adam Jiang wrote:
>
> >Add stackoverflow detection to mips arch
>
> [...]
>
> >diff --git a/arch/mips/kernel/irq.c b/arch/mips/kernel/irq.c
> >index c6345f5..8fdf79e 100644
> >--- a/arch/mips/kernel/irq.c
> >+++ b/arch/mips/kernel/irq.c
> >@@ -151,6 +151,25 @@ void __init init_IRQ(void)
> > #endif
> > }
> >+#ifdef DEBUG_STACKOVERFLOW
> >+static inline void check_stack_overflow(void)
> >+{
> >+ long sp;
> >+
> >+ asm volatile("move %0, $sp" : "=r" (sp));
> >+ sp = sp & (THREAD_SIZE-1);
> >+
> >+ /* check for stack overflow: is there less than 2KB free? */
> >+ if (unlikely(sp < (sizeof(struct thread_info) + 2048))) {
> >+ printk("do_IRQ: stack overflow: %ld\n",
> >+ sp - sizeof(struct thread_info));
> >+ dump_stack();
> >+ }
> >+}
> >+#else
> >+static inline void check_stack_overflow(void) {}
> >+#endif
> >+
> > /*
> > * do_IRQ handles all normal device IRQ's (the special
> > * SMP cross-CPU interrupts have their own specific
>
> You've dropped call check_stack_overflow() call in do_IRQ() --
> was that intentional?

Of course NO. It is awful, I have say.

I spent a lot of time to struggle with git yesterday. When I revised the
coding style problem and tried to format-patch to master branch, then I
got 2 patches but not all in one. How could I rebase my working copy and
get an all-in-one patch of this?

I tried to revert my commit and redo this patch, then I lost to calling
it in do_IRQ();

Best regards,
/Adam

>
> WBR, Sergei