2010-08-26 03:56:09

by Adam Jiang

Subject: [PATCH 3/3] mips: irq: add stackoverflow detection

Add stackoverflow detection to mips arch
---
arch/mips/Kconfig.debug | 7 +++++++
arch/mips/kernel/irq.c | 22 ++++++++++++++++++++++
2 files changed, 29 insertions(+), 0 deletions(-)

diff --git a/arch/mips/Kconfig.debug b/arch/mips/Kconfig.debug
index 43dc279..30c58d4 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..75c584d 100644
--- a/arch/mips/kernel/irq.c
+++ b/arch/mips/kernel/irq.c
@@ -151,6 +151,25 @@ void __init init_IRQ(void)
#endif
}

+#ifdef CONFIG_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
@@ -159,6 +178,9 @@ void __init init_IRQ(void)
void __irq_entry do_IRQ(unsigned int irq)
{
irq_enter();
+
+ check_stack_overflow();
+
__DO_IRQ_SMTC_HOOK(irq);
generic_handle_irq(irq);
irq_exit();
--
1.7.0.4

2010-08-26 08:29:17

by Sergei Shtylyov

Subject: Re: [PATCH 3/3] 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..75c584d 100644
> --- a/arch/mips/kernel/irq.c
> +++ b/arch/mips/kernel/irq.c
> @@ -151,6 +151,25 @@ void __init init_IRQ(void)
> #endif
> }
>
> +#ifdef CONFIG_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)

You didn't even try to compile with the option disabled -- you've missed {}.

> +#endif
> +
> /*
> * do_IRQ handles all normal device IRQ's (the special
> * SMP cross-CPU interrupts have their own specific

WBR, Sergei

2010-08-26 13:15:13

by Adam Jiang

Subject: Re: [PATCH 3/3] mips: irq: add stackoverflow detection

2010/8/26 Sergei Shtylyov <[email protected]>:
> 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..75c584d 100644
>> --- a/arch/mips/kernel/irq.c
>> +++ b/arch/mips/kernel/irq.c
>> @@ -151,6 +151,25 @@ void __init init_IRQ(void)
>> ?#endif
>> ?}
>> ?+#ifdef CONFIG_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)
>
> ? You didn't even try to compile with the option disabled -- you've missed
> {}.

Thank your, Sergei.

This is my first patch. I realized I have to learn much to summit a
good patch. And yes, I have to pay more attention on my code. Anyway,
I will try to get a good patch and send it here again.

/Adam

>
>> +#endif
>> +
>> ?/*
>> ?* do_IRQ handles all normal device IRQ's (the special
>> ?* SMP cross-CPU interrupts have their own specific
>
> WBR, Sergei
>