[PATCH 3/3] mm: Temporarily disable grub_mm_debug while calling grub_vprintf in grub_printf

[Glenn Washburn]

To prevent infinite recursion when grub_mm_debug is on, disable it when
calling grub_vprintf. One such call loop is:
  grub_vprintf -> parse_printf_args -> parse_printf_arg_fmt
    -> grub_debug_calloc -> grub_printf -> grub_vprintf

Signed-off-by: Glenn Washburn <development@efficientek.com>
---
 grub-core/kern/misc.c | 19 +++++++++++++++++++
 1 file changed, 19 insertions(+)

diff --git a/grub-core/kern/misc.c b/grub-core/kern/misc.c
index de40f566d6..cd6f460a21 100644
--- a/grub-core/kern/misc.c
+++ b/grub-core/kern/misc.c
@@ -113,10 +113,29 @@ grub_printf (const char *fmt, ...)
   va_list ap;
   int ret;
 
+#if defined(MM_DEBUG) && !defined(GRUB_UTIL) && !defined (GRUB_MACHINE_EMU)
+  /*
+   * To prevent infinite recursion when grub_mm_debug is on, disable it
+   * when calling grub_vprintf. One such call loop is:
+   *   grub_vprintf -> parse_printf_args -> parse_printf_arg_fmt
+   *     -> grub_debug_calloc -> grub_printf -> grub_vprintf
+   */
+  int grub_mm_debug_save = 0;
+  if (grub_mm_debug)
+    {
+      grub_mm_debug_save = grub_mm_debug;
+      grub_mm_debug = 0;
+    }
+#endif
+
   va_start (ap, fmt);
   ret = grub_vprintf (fmt, ap);
   va_end (ap);
 
+#if defined(MM_DEBUG) && !defined(GRUB_UTIL) && !defined (GRUB_MACHINE_EMU)
+  grub_mm_debug = grub_mm_debug_save;
+#endif
+
   return ret;
 }
 
-- 
2.27.0