[syslinux:elflink] extlinux: Handle error case for find_mount()

[syslinux-bot for Matt Fleming]

Commit-ID:  040f273035ca84fc963d0d0c0b39794f7a5fc7d4
Gitweb:     http://www.syslinux.org/commit/040f273035ca84fc963d0d0c0b39794f7a5fc7d4
Author:     Matt Fleming <matt.fleming at intel.com>
AuthorDate: Fri, 14 Sep 2012 14:54:40 +0100
Committer:  Matt Fleming <matt.fleming at intel.com>
CommitDate: Fri, 14 Sep 2012 14:54:40 +0100

extlinux: Handle error case for find_mount()

find_mount() may return NULL, so we'd really better check for that
*before* dereferencing the pointer.

Signed-off-by: Matt Fleming <matt.fleming at intel.com>

---
 extlinux/main.c |    2 ++
 1 files changed, 2 insertions(+), 0 deletions(-)

diff --git a/extlinux/main.c b/extlinux/main.c
index 73f3fbe..d7a239e 100644
--- a/extlinux/main.c
+++ b/extlinux/main.c
@@ -915,6 +915,8 @@ static const char *find_device_mountinfo(const char *path, dev_t dev)
     struct stat st;
 
     m = find_mount(path, NULL);
+    if (!m)
+	return NULL;
 
     if (m->devpath[0] == '/' && m->dev == dev &&
 	!stat(m->devpath, &st) && S_ISBLK(st.st_mode) && st.st_rdev == dev)