[PATCH v2] IOMUX: Fix access past end of console_devices

[Sean Anderson]

We should only access console_devices[file][i] once we have checked that i
< cd_count[file]. Otherwise, we will access uninitialized memory at the end
of the loop. console_devices[file][i] should not be NULL, but putting the
assignment in the loop condition allows us to ensure that i is checked
beforehand. This isn't a bug, but it does make valgrind stop complaining.

Fixes: 400797cad3 ("IOMUX: Split out for_each_console_dev() helper macro")
Signed-off-by: Sean Anderson <seanga2 at gmail.com>
Reviewed-by: Andrew Scull <ascull at google.com>
---

Changes in v2:
- Put each clause of the for loop on its own line

 include/iomux.h | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/include/iomux.h b/include/iomux.h
index 37f5f6dee6..35caa697eb 100644
--- a/include/iomux.h
+++ b/include/iomux.h
@@ -24,10 +24,10 @@ extern struct stdio_dev **console_devices[MAX_FILES];
  */
 extern int cd_count[MAX_FILES];
 
-#define for_each_console_dev(i, file, dev)		\
-	for (i = 0, dev = console_devices[file][i];	\
-	     i < cd_count[file];			\
-	     i++, dev = console_devices[file][i])
+#define for_each_console_dev(i, file, dev)				\
+	for (i = 0;							\
+	     i < cd_count[file] && (dev = console_devices[file][i]);	\
+	     i++)
 
 int iomux_match_device(struct stdio_dev **, const int, struct stdio_dev *);
 int iomux_doenv(const int, const char *);
-- 
2.35.1