Merge branch 'riscv' of g.csail.mit.edu:xv6-dev into riscv

kernel/kalloc.c

@@ -39,7 +39,7 @@ freerange(void *pa_start, void *pa_end)
     kfree(p);
 }
 
-// Free the page of physical memory pointed at by v,
+// Free the page of physical memory pointed at by pa,
 // which normally should have been returned by a
 // call to kalloc().  (The exception is when
 // initializing the allocator; see kinit above.)

kernel/printf.c

@@ -109,6 +109,7 @@ printf(char *fmt, ...)
       break;
     }
   }
+  va_end(ap);
 
   if(locking)
     release(&pr.lock);