Blackfin arch: Add one more check on `fp' to prevent double fault

Signed-off-by: Jie Zhang <jie.zhang@analog.com>
Signed-off-by: Bryan Wu <cooloney@kernel.org>

1 files changed, 3 insertions, 5 deletions

diff --git a/arch/blackfin/kernel/traps.c b/arch/blackfin/kernel/traps.c
index f18c2481e9b7..79926413c0eb 100644
--- a/arch/blackfin/kernel/traps.c
+++ b/arch/blackfin/kernel/traps.c
@@ -820,11 +820,8 @@ void show_stack(struct task_struct *task, unsigned long *stack)
         decode_address(buf, (unsigned int)stack);
         printk(KERN_NOTICE " SP: [0x%p] %s\n", stack, buf);
 
-        addr = (unsigned int *)((unsigned int)stack & ~0x3F);
-
         /* First thing is to look for a frame pointer */
-        for (addr = (unsigned int *)((unsigned int)stack & ~0xF), i = 0;
-                addr < endstack; addr++, i++) {
+        for (addr = (unsigned int *)((unsigned int)stack & ~0xF); addr < endstack; addr++) {
                 if (*addr & 0x1)
                         continue;
                 ins_addr = (unsigned short *)*addr;
@@ -834,7 +831,8 @@ void show_stack(struct task_struct *task, unsigned long *stack)
 
                 if (fp) {
                         /* Let's check to see if it is a frame pointer */
-                        while (fp >= (addr - 1) && fp < endstack && fp)
+                        while (fp >= (addr - 1) && fp < endstack
+                               && fp && ((unsigned int) fp & 0x3) == 0)
                                 fp = (unsigned int *)*fp;
                         if (fp == 0 || fp == endstack) {
                                 fp = addr - 1;