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>

diff --git a/drivers/video/s3c-fb.c b/drivers/video/s3c-fb.c
index b00c064..77f5765 100644 (file)
--- 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;