of: Fix crash if an earlycon driver is not found
authorKevin Cernekee <cernekee@gmail.com>
Sun, 9 Nov 2014 08:55:47 +0000 (00:55 -0800)
committerRob Herring <robh@kernel.org>
Tue, 18 Nov 2014 17:35:02 +0000 (11:35 -0600)
__earlycon_of_table_sentinel.compatible is a char[128], not a pointer, so
it will never be NULL.  Checking it against NULL causes the match loop to
run past the end of the array, and eventually match a bogus entry, under
the following conditions:

 - Kernel command line specifies "earlycon" with no parameters
 - DT has a stdout-path pointing to a UART node
 - The UART driver doesn't use OF_EARLYCON_DECLARE (or maybe the console
   driver is compiled out)

Fix this by checking to see if match->compatible is a non-empty string.

Signed-off-by: Kevin Cernekee <cernekee@gmail.com>
Cc: <stable@vger.kernel.org> # 3.16+
Signed-off-by: Rob Herring <robh@kernel.org>
drivers/of/fdt.c

index d1ffca8b34eac51853c812a230cfd438862f8cff..30e97bcc4f88293ff902df937446d0983db6d4f3 100644 (file)
@@ -773,7 +773,7 @@ int __init early_init_dt_scan_chosen_serial(void)
        if (offset < 0)
                return -ENODEV;
 
-       while (match->compatible) {
+       while (match->compatible[0]) {
                unsigned long addr;
                if (fdt_node_check_compatible(fdt, offset, match->compatible)) {
                        match++;