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-rw-r--r--arch/avr32/kernel/traps.c52
1 files changed, 29 insertions, 23 deletions
diff --git a/arch/avr32/kernel/traps.c b/arch/avr32/kernel/traps.c
index 7e803f4d7a12..adc01a12d154 100644
--- a/arch/avr32/kernel/traps.c
+++ b/arch/avr32/kernel/traps.c
@@ -49,39 +49,45 @@ out:
return;
}
+static inline int valid_stack_ptr(struct thread_info *tinfo, unsigned long p)
+{
+ return (p > (unsigned long)tinfo)
+ && (p < (unsigned long)tinfo + THREAD_SIZE - 3);
+}
+
#ifdef CONFIG_FRAME_POINTER
static inline void __show_trace(struct task_struct *tsk, unsigned long *sp,
struct pt_regs *regs)
{
- unsigned long __user *fp;
- unsigned long __user *last_fp = NULL;
-
- if (regs) {
- fp = (unsigned long __user *)regs->r7;
- } else if (tsk == current) {
- register unsigned long __user *real_fp __asm__("r7");
- fp = real_fp;
- } else {
- fp = (unsigned long __user *)tsk->thread.cpu_context.r7;
- }
+ unsigned long lr, fp;
+ struct thread_info *tinfo;
+
+ tinfo = (struct thread_info *)
+ ((unsigned long)sp & ~(THREAD_SIZE - 1));
+
+ if (regs)
+ fp = regs->r7;
+ else if (tsk == current)
+ asm("mov %0, r7" : "=r"(fp));
+ else
+ fp = tsk->thread.cpu_context.r7;
/*
- * Walk the stack until (a) we get an exception, (b) the frame
- * pointer becomes zero, or (c) the frame pointer gets stuck
- * at the same value.
+ * Walk the stack as long as the frame pointer (a) is within
+ * the kernel stack of the task, and (b) it doesn't move
+ * downwards.
*/
- while (fp && fp != last_fp) {
- unsigned long lr, new_fp = 0;
-
- last_fp = fp;
- if (__get_user(lr, fp))
- break;
- if (fp && __get_user(new_fp, fp + 1))
- break;
- fp = (unsigned long __user *)new_fp;
+ while (valid_stack_ptr(tinfo, fp)) {
+ unsigned long new_fp;
+ lr = *(unsigned long *)fp;
printk(" [<%08lx>] ", lr);
print_symbol("%s\n", lr);
+
+ new_fp = *(unsigned long *)(fp + 4);
+ if (new_fp <= fp)
+ break;
+ fp = new_fp;
}
printk("\n");
}