sparc64: Tighten checks in kstack_valid().

The kernel stack pointer is invalid if it is not 16-byte
aligned.

Based upon a report by Meelis Roos <mroos@linux.ee>

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 4 insertions, 0 deletions

diff --git a/arch/sparc/kernel/kstack.h b/arch/sparc/kernel/kstack.h
index 4248d969272f..5247283d1c03 100644
--- a/arch/sparc/kernel/kstack.h
+++ b/arch/sparc/kernel/kstack.h
@@ -11,6 +11,10 @@ static inline bool kstack_valid(struct thread_info *tp, unsigned long sp)
 {
         unsigned long base = (unsigned long) tp;
 
+        /* Stack pointer must be 16-byte aligned.  */
+        if (sp & (16UL - 1))
+                return false;
+
         if (sp >= (base + sizeof(struct thread_info)) &&
             sp <= (base + THREAD_SIZE - sizeof(struct sparc_stackf)))
                 return true;