[PATCH] x86: clean up stack overflow debug check

From: Ingo Molnar
Date: Sun Nov 23 2008 - 03:02:26 EST


Impact: cleanup

Simplify the irq-sampled stack overflow debug check:

- eliminate an #idef

- use WARN_ONCE() to emit a single warning (all bets are off
after the first such warning anyway)

Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
arch/x86/kernel/irq_64.c | 25 ++++++++++---------------
1 files changed, 10 insertions(+), 15 deletions(-)

diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index b842fc8..1d3d0e7 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -18,7 +18,6 @@
#include <asm/idle.h>
#include <asm/smp.h>

-#ifdef CONFIG_DEBUG_STACKOVERFLOW
/*
* Probabilistic stack overflow check:
*
@@ -28,20 +27,18 @@
*/
static inline void stack_overflow_check(struct pt_regs *regs)
{
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
u64 curbase = (u64)task_stack_page(current);
- static unsigned long warned = INITIAL_JIFFIES - 60*HZ;
-
- if (regs->sp >= curbase && regs->sp <= curbase + THREAD_SIZE &&
- regs->sp < curbase + sizeof(struct thread_info) +
- sizeof(struct pt_regs) + 128 &&
- time_after(jiffies, warned + 60*HZ)) {
- printk("do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n",
- current->comm, curbase, regs->sp);
- show_stack(NULL,NULL);
- warned = jiffies;
- }
-}
+
+ WARN_ONCE(regs->sp >= curbase &&
+ regs->sp <= curbase + THREAD_SIZE &&
+ regs->sp < curbase + sizeof(struct thread_info) +
+ sizeof(struct pt_regs) + 128,
+
+ "do_IRQ: %s near stack overflow (cur:%Lx,sp:%lx)\n",
+ current->comm, curbase, regs->sp);
#endif
+}

/*
* do_IRQ handles all normal device IRQ's (the special
@@ -61,9 +58,7 @@ asmlinkage unsigned int do_IRQ(struct pt_regs *regs)
irq_enter();
irq = __get_cpu_var(vector_irq)[vector];

-#ifdef CONFIG_DEBUG_STACKOVERFLOW
stack_overflow_check(regs);
-#endif

desc = irq_to_desc(irq);
if (likely(desc))
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/