kexec: avoid freeing NULL pointer in image_crash_alloc()

Though there is no error if we free a NULL pointer, I think we could
avoid this behaviour.  Change the code a little in kimage_crash_alloc()
could avoid this kind of unnecessary free.

Signed-off-by: Zhang Yanfei <zhangyanfei@cn.fujitsu.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Sasha Levin <sasha.levin@oracle.com>
Reviewed-by: Simon Horman <horms@verge.net.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/kernel/kexec.c b/kernel/kexec.c
index 6b7455e..bddd3d7 100644 (file)
--- a/kernel/kexec.c
+++ b/kernel/kexec.c
@@ -316,7 +316,7 @@ static int kimage_crash_alloc(struct kimage **rimage, unsigned long entry,
                mend = mstart + image->segment[i].memsz - 1;
                /* Ensure we are within the crash kernel limits */
                if ((mstart < crashk_res.start) || (mend > crashk_res.end))
-                       goto out;
+                       goto out_free;
        }
 
        /*
@@ -329,16 +329,15 @@ static int kimage_crash_alloc(struct kimage **rimage, unsigned long entry,
                                           get_order(KEXEC_CONTROL_PAGE_SIZE));
        if (!image->control_code_page) {
                printk(KERN_ERR "Could not allocate control_code_buffer\n");
-               goto out;
+               goto out_free;
        }
 
-       result = 0;
-out:
-       if (result == 0)
-               *rimage = image;
-       else
-               kfree(image);
+       *rimage = image;
+       return 0;
 
+out_free:
+       kfree(image);
+out:
        return result;
 }