#include <linux/sched.h>
#include <linux/mm.h>
#include <asm/ptrace.h>
+#include <asm/uaccess.h>
struct frame_head {
struct frame_head * ebp;
static struct frame_head *
dump_backtrace(struct frame_head * head)
{
- oprofile_add_trace(head->ret);
+ struct frame_head bufhead[2];
- /* frame pointers should strictly progress back up the stack
- * (towards higher addresses) */
- if (head >= head->ebp)
+ /* Also check accessibility of one struct frame_head beyond */
+ if (!access_ok(VERIFY_READ, head, sizeof(bufhead)))
+ return NULL;
+ if (__copy_from_user_inatomic(bufhead, head, sizeof(bufhead)))
return NULL;
- return head->ebp;
-}
-
-/* check that the page(s) containing the frame head are present */
-static int pages_present(struct frame_head * head)
-{
- struct mm_struct * mm = current->mm;
+ oprofile_add_trace(bufhead[0].ret);
- /* FIXME: only necessary once per page */
- if (!check_user_page_readable(mm, (unsigned long)head))
- return 0;
+ /* frame pointers should strictly progress back up the stack
+ * (towards higher addresses) */
+ if (head >= bufhead[0].ebp)
+ return NULL;
- return check_user_page_readable(mm, (unsigned long)(head + 1));
+ return bufhead[0].ebp;
}
/*
return;
}
-#ifdef CONFIG_SMP
- if (!spin_trylock(¤t->mm->page_table_lock))
- return;
-#endif
-
- while (depth-- && head && pages_present(head))
+ while (depth-- && head)
head = dump_backtrace(head);
-
-#ifdef CONFIG_SMP
- spin_unlock(¤t->mm->page_table_lock);
-#endif
}