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

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

[Adam Jiang]

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

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

[Sergei Shtylyov]

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

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

[Adam Jiang]

2010/8/26 Sergei Shtylyov <sshtylyov@mvista.com>:
> 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
>