From: Hajime Tazaki <thehajime@gmail.com>
Date: Mon, 21 Dec 2020 02:24:34 +0000 (+0900)
Subject: um: ubd: fix command line handling of ubd
X-Git-Url: http://git.maquefel.me/?a=commitdiff_plain;h=94c41b3a7c370b0d6afc5ace8fafa0531865a940;p=linux.git

um: ubd: fix command line handling of ubd

This commit fixes a regression to handle command line parameters of ubd.
With a simple line "./linux ubd0="./disk-ext4.img", it fails at
ubd_setup_common().  The commit adds additional checks to the variables
in order to properly parse the paremeters which previously worked.

Fixes: ef3ba87cb7c9 ("um: ubd: Set device serial attribute from cmdline")
Cc: Christopher Obbard <chris.obbard@collabora.com>
Signed-off-by: Hajime Tazaki <thehajime@gmail.com>
Acked-by: Christopher Obbard <chris.obbard@collabora.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
---

diff --git a/arch/um/drivers/ubd_kern.c b/arch/um/drivers/ubd_kern.c
index 13b1fe694b904..bd16b17ba4d63 100644
--- a/arch/um/drivers/ubd_kern.c
+++ b/arch/um/drivers/ubd_kern.c
@@ -375,11 +375,11 @@ break_loop:
 		file = NULL;
 
 	backing_file = strsep(&str, ",:");
-	if (*backing_file == '\0')
+	if (backing_file && *backing_file == '\0')
 		backing_file = NULL;
 
 	serial = strsep(&str, ",:");
-	if (*serial == '\0')
+	if (serial && *serial == '\0')
 		serial = NULL;
 
 	if (backing_file && ubd_dev->no_cow) {