fbdev: sh_mobile_lcdcfb: fix more error paths

This patch fixes the following two erroneous error paths:

hw_usecnt is allocated with a value of 0, therefore in an early error case,
calling sh_mobile_lcdc_clk_off() will wrongly conclude, that hw_usecnt has
already been incremented. Then sh_mobile_lcdc_runtime_suspend() will be called,
which will access uninitialised data fields and crash the kernel.

sh_mobile_lcdc_stop() can be called before framebuffer has been allocated, then
ch->info is NULL and dereferencing it will Oops too.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>

diff --git a/drivers/video/sh_mobile_lcdcfb.c b/drivers/video/sh_mobile_lcdcfb.c
index 43132de388220716eb604f440f74e0429d04cfc0..295bf4ba18491775b9c8d86b50031e28b0b66656 100644 (file)
--- a/drivers/video/sh_mobile_lcdcfb.c
+++ b/drivers/video/sh_mobile_lcdcfb.c
@@ -614,7 +614,7 @@ static void sh_mobile_lcdc_stop(struct sh_mobile_lcdc_priv *priv)
                 * flush frame, and wait for frame end interrupt
                 * clean up deferred io and enable clock
                 */
-               if (ch->info->fbdefio) {
+               if (ch->info && ch->info->fbdefio) {
                        ch->frame_end = 0;
                        schedule_delayed_work(&ch->info->deferred_work, 0);
                        wait_event(ch->frame_end_wait, ch->frame_end);
@@ -704,7 +704,6 @@ static int sh_mobile_lcdc_setup_clocks(struct platform_device *pdev,
                        return PTR_ERR(priv->dot_clk);
                }
        }
-       atomic_set(&priv->hw_usecnt, -1);
 
        /* Runtime PM support involves two step for this driver:
         * 1) Enable Runtime PM
@@ -1055,6 +1054,7 @@ static int __devinit sh_mobile_lcdc_probe(struct platform_device *pdev)
 
        priv->irq = i;
        pdata = pdev->dev.platform_data;
+       atomic_set(&priv->hw_usecnt, -1);
 
        j = 0;
        for (i = 0; i < ARRAY_SIZE(pdata->ch); i++) {