[IA64] Correct convert_to_non_syscall()

convert_to_non_syscall() has the same problem that unwind_to_user()
used to have.  Fix it likewise.

Signed-off-by: David Mosberger-Tang <davidm@hpl.hp.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

1 files changed, 17 insertions, 3 deletions

diff --git a/arch/ia64/kernel/ptrace.c b/arch/ia64/kernel/ptrace.c
index 907464ee7273..08c8a5eb25ab 100644
--- a/arch/ia64/kernel/ptrace.c
+++ b/arch/ia64/kernel/ptrace.c
@@ -692,16 +692,30 @@ convert_to_non_syscall (struct task_struct *child, struct pt_regs  *pt,
                         unsigned long cfm)
 {
         struct unw_frame_info info, prev_info;
-        unsigned long ip, pr;
+        unsigned long ip, sp, pr;
 
         unw_init_from_blocked_task(&info, child);
         while (1) {
                 prev_info = info;
                 if (unw_unwind(&info) < 0)
                         return;
-                if (unw_get_rp(&info, &ip) < 0)
+
+                unw_get_sp(&info, &sp);
+                if ((long)((unsigned long)child + IA64_STK_OFFSET - sp)
+                    < IA64_PT_REGS_SIZE) {
+                        dprintk("ptrace.%s: ran off the top of the kernel "
+                                "stack\n", __FUNCTION__);
+                        return;
+                }
+                if (unw_get_pr (&prev_info, &pr) < 0) {
+                        unw_get_rp(&prev_info, &ip);
+                        dprintk("ptrace.%s: failed to read "
+                                "predicate register (ip=0x%lx)\n",
+                                __FUNCTION__, ip);
                         return;
-                if (ip < FIXADDR_USER_END)
+                }
+                if (unw_is_intr_frame(&info)
+                    && (pr & (1UL << PRED_USER_STACK)))
                         break;
         }