x86_64: fix the check in stack_overflow_check

Impact: make stack overflow debug check and printout narrower

stack_overflow_check() should consider the stack usage of pt_regs, and
thus it could warn us in advance. Additionally, it looks better for
the warning time to start at INITIAL_JIFFIES.

Assuming that rsp gets close to the check point before interrupt
arrives: when interrupt really happens, thread_info will be partly
overrode.

Signed-off-by: jia zhang <jia.zhang2008@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 4 insertions, 3 deletions

diff --git a/arch/x86/kernel/irq_64.c b/arch/x86/kernel/irq_64.c
index 60eb84eb77a..b842fc82be1 100644
--- a/arch/x86/kernel/irq_64.c
+++ b/arch/x86/kernel/irq_64.c
@@ -29,11 +29,12 @@
 static inline void stack_overflow_check(struct pt_regs *regs)
 {
         u64 curbase = (u64)task_stack_page(current);
-        static unsigned long warned = -60*HZ;
+        static unsigned long warned = INITIAL_JIFFIES - 60*HZ;
 
         if (regs->sp >= curbase && regs->sp <= curbase + THREAD_SIZE &&
-            regs->sp <  curbase + sizeof(struct thread_info) + 128 &&
-            time_after(jiffies, warned + 60*HZ)) {
+                        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);