s3c-fb: fix various null references on framebuffer memory alloc failure

The following problems were found in the above situation:

sfb->windows[win] was being assigned at the end of s3c_fb_probe_win only.
This resulted in passing a NULL to s3c_fb_release_win if probe_win
returned early and a memory leak.

dma_free_writecombine does not allow its third argument to be NULL.

fb_dealloc_cmap does not verify whether its argument is not NULL.

Signed-off-by: Pawel Osciak <p.osciak@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: InKi Dae <inki.dae@samsung.com>
Cc: Ben Dooks <ben-linux@fluff.org>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 3 deletions

diff --git a/drivers/video/s3c-fb.c b/drivers/video/s3c-fb.c
index b00c064beddf..77f576589a89 100644
--- a/drivers/video/s3c-fb.c
+++ b/drivers/video/s3c-fb.c
@@ -804,7 +804,8 @@ static void s3c_fb_free_memory(struct s3c_fb *sfb, struct s3c_fb_win *win)
 {
         struct fb_info *fbi = win->fbinfo;
 
-        dma_free_writecombine(sfb->dev, PAGE_ALIGN(fbi->fix.smem_len),
+        if (fbi->screen_base)
+                dma_free_writecombine(sfb->dev, PAGE_ALIGN(fbi->fix.smem_len),
                               fbi->screen_base, fbi->fix.smem_start);
 }
 
@@ -819,7 +820,8 @@ static void s3c_fb_release_win(struct s3c_fb *sfb, struct s3c_fb_win *win)
 {
         if (win->fbinfo) {
                 unregister_framebuffer(win->fbinfo);
-                fb_dealloc_cmap(&win->fbinfo->cmap);
+                if (win->fbinfo->cmap.len)
+                        fb_dealloc_cmap(&win->fbinfo->cmap);
                 s3c_fb_free_memory(sfb, win);
                 framebuffer_release(win->fbinfo);
         }
@@ -865,6 +867,7 @@ static int __devinit s3c_fb_probe_win(struct s3c_fb *sfb, unsigned int win_no,
         WARN_ON(windata->win_mode.yres == 0);
 
         win = fbinfo->par;
+        *res = win;
         var = &fbinfo->var;
         win->variant = *variant;
         win->fbinfo = fbinfo;
@@ -939,7 +942,6 @@ static int __devinit s3c_fb_probe_win(struct s3c_fb *sfb, unsigned int win_no,
                 return ret;
         }
 
-        *res = win;
         dev_info(sfb->dev, "window %d: fb %s\n", win_no, fbinfo->fix.id);
 
         return 0;