[PATCH] x86_64: (resend) x86_64 stack overflow debugging
Take two, now without spurious whitespace :( Applies to git & 2.6.17-rc6
CONFIG_DEBUG_STACKOVERFLOW existed for x86_64 in 2.4, but seems to have gone AWOL in 2.6.
I've pretty much just copied this over from the 2.4 code, with
appropriate tweaks for the 2.6 kernel, plus a bugfix. I'd personally
rather see it printed out the way other arches do it, i.e.
bytes-remaining-until-overflow, rather than having to do the subtraction
yourself. Also, only 128 bytes remaining seems awfully late to issue a
warning. But I'll start here :)
Signed-off-by: Eric Sandeen <sandeen@sgi.com>
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/arch/x86_64/kernel/irq.c b/arch/x86_64/kernel/irq.c
index 207ecdc..59518d4 100644
--- a/arch/x86_64/kernel/irq.c
+++ b/arch/x86_64/kernel/irq.c
@@ -26,6 +26,30 @@
#endif
#endif
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+/*
+ * Probabilistic stack overflow check:
+ *
+ * Only check the stack in process context, because everything else
+ * runs on the big interrupt stacks. Checking reliably is too expensive,
+ * so we just check from interrupts.
+ */
+static inline void stack_overflow_check(struct pt_regs *regs)
+{
+ u64 curbase = (u64) current->thread_info;
+ static unsigned long warned = -60*HZ;
+
+ if (regs->rsp >= curbase && regs->rsp <= curbase + THREAD_SIZE &&
+ regs->rsp < curbase + sizeof(struct thread_info) + 128 &&
+ time_after(jiffies, warned + 60*HZ)) {
+ printk("do_IRQ: %s near stack overflow (cur:%Lx,rsp:%lx)\n",
+ current->comm, curbase, regs->rsp);
+ show_stack(NULL,NULL);
+ warned = jiffies;
+ }
+}
+#endif
+
/*
* Generic, controller-independent functions:
*/
@@ -96,7 +120,9 @@
exit_idle();
irq_enter();
-
+#ifdef CONFIG_DEBUG_STACKOVERFLOW
+ stack_overflow_check(regs);
+#endif
__do_IRQ(irq, regs);
irq_exit();