Ok, we should fix that. We should just make it look like all other stack
frames.
There is other code in the kernel that "knows" that all kernel stacks have
the fields for the user stack return on it, namely the ptrace code etc.
Now, the initial stack is hopefully never *accessed* by that kind of code,
but this kind of special-case code is just wrong.
Well, we might as well then just make the code readable instead. IOW, how
about this one, which just declares a structure that describes the stack
frame thing? That just makes everything clearer, since we can then use
"sizeof(that structure)" instead of using the magic "2*sizeof(unsigned
long)".
Linus
---
diff --git a/arch/i386/kernel/traps.c b/arch/i386/kernel/traps.c
index cfffe3d..47b0bef 100644
--- a/arch/i386/kernel/traps.c
+++ b/arch/i386/kernel/traps.c
@@ -100,36 +100,45 @@ asmlinkage void machine_check(void);
int kstack_depth_to_print = 24;
static unsigned int code_bytes = 64;
-static inline int valid_stack_ptr(struct thread_info *tinfo, void *p)
+static inline int valid_stack_ptr(struct thread_info *tinfo, void *p, unsigned size)
{
return p > (void *)tinfo &&
- p < (void *)tinfo + THREAD_SIZE - 3;
+ p <= (void *)tinfo + THREAD_SIZE - size;
}
+/* The form of the top of the frame on the stack */
+struct stack_frame {
+ struct stack_frame *next_frame;
+ unsigned long return_address;
+};
+
static inline unsigned long print_context_stack(struct thread_info *tinfo,
unsigned long *stack, unsigned long ebp,
struct stacktrace_ops *ops, void *data)
{
- unsigned long addr;
-
#ifdef CONFIG_FRAME_POINTER
- while (valid_stack_ptr(tinfo, (void *)ebp)) {
- unsigned long new_ebp;
- addr = *(unsigned long *)(ebp + 4);
+ struct stack_frame *frame = (struct stack_frame *)ebp;
+ while (valid_stack_ptr(tinfo, frame, sizeof(*frame))) {
+ struct stack_frame *next;
+ unsigned long addr;
+
+ addr = frame->return_address;
ops->address(data, addr);
/*
* break out of recursive entries (such as
* end_of_stack_stop_unwind_function). Also,
* we can never allow a frame pointer to
* move downwards!
- */
- new_ebp = *(unsigned long *)ebp;
- if (new_ebp <= ebp)
+ */
+ next = frame->next_frame;
+ if (next <= frame)
break;
- ebp = new_ebp;
+ frame = next;
}
#else
- while (valid_stack_ptr(tinfo, stack)) {
+ while (valid_stack_ptr(tinfo, stack, sizeof(*stack))) {
+ unsigned long addr;
+
addr = *stack++;
if (__kernel_text_address(addr))
ops->address(data, addr);
-
