1 files changed, 19 insertions, 3 deletions

diff --git a/arch/x86/kernel/dumpstack_32.c b/arch/x86/kernel/dumpstack_32.c
index 50076d4366c4..2d65cfa5e0b4 100644
--- a/arch/x86/kernel/dumpstack_32.c
+++ b/arch/x86/kernel/dumpstack_32.c
@@ -89,16 +89,32 @@ int get_stack_info(unsigned long *stack, struct task_struct *task,
         task = task ? : current;
 
         if (in_task_stack(stack, task, info))
-                return 0;
+                goto recursion_check;
 
         if (task != current)
                 goto unknown;
 
         if (in_hardirq_stack(stack, info))
-                return 0;
+                goto recursion_check;
 
         if (in_softirq_stack(stack, info))
-                return 0;
+                goto recursion_check;
+
+        goto unknown;
+
+recursion_check:
+        /*
+         * Make sure we don't iterate through any given stack more than once.
+         * If it comes up a second time then there's something wrong going on:
+         * just break out and report an unknown stack type.
+         */
+        if (visit_mask) {
+                if (*visit_mask & (1UL << info->type))
+                        goto unknown;
+                *visit_mask |= 1UL << info->type;
+        }
+
+        return 0;
 
 unknown:
         info->type = STACK_TYPE_UNKNOWN;