printk: handle blank console arguments passed in.

If uboot passes a blank string to console_setup then it results in
a trashed memory. Ultimately, the kernel crashes during freeing up
the memory.

This fix checks if there is a blank parameter being
passed to console_setup from uboot. In case it detects that
the console parameter is blank then it doesn't setup the serial
device and it gracefully exits.

Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Shreyas Joshi <[email protected]>
Acked-by: Sergey Senozhatsky <[email protected]>
[[email protected]: Better format the commit message and code, remove unnecessary brackets.]
Signed-off-by: Petr Mladek <[email protected]>

diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c
index 35cc5f54886030e630c8e3513f6aac998b8a31e2..a3990505abdf84c48715bddc6e7ea43b48c38725 100644 (file)
--- a/kernel/printk/printk.c
+++ b/kernel/printk/printk.c
@@ -2200,6 +2200,9 @@ static int __init console_setup(char *str)
        char *s, *options, *brl_options = NULL;
        int idx;
 
+       if (str[0] == 0)
+               return 1;
+
        if (_braille_console_setup(&str, &brl_options))
                return 1;