watchdog: imgpdc: Fix probe NULL pointer dereference

James Hogan · Wim Van Sebroeck · commit a629c08fdb98 · 2015-03-27T08:47:42.000+01:00
The IMG PDC watchdog probe function calls pdc_wdt_stop() prior to watchdog_set_drvdata(), causing a NULL pointer dereference when pdc_wdt_stop() retrieves the struct pdc_wdt_dev pointer using watchdog_get_drvdata() and reads the register base address through it. Fix by moving the watchdog_set_drvdata() call earlier, to where various other pdc_wdt->wdt_dev fields are initialised. Fixes: 9393766 ("watchdog: ImgTec PDC Watchdog Timer Driver") Signed-off-by: James Hogan <james.hogan@imgtec.com> Cc: Ezequiel Garcia <ezequiel.garcia@imgtec.com> Cc: Naidu Tellapati <Naidu.Tellapati@imgtec.com> Cc: Jude Abraham <Jude.Abraham@imgtec.com> Cc: linux-watchdog@vger.kernel.org Reviewed-by: Guenter Roeck <linux@roeck-us.net> Signed-off-by: Wim Van Sebroeck <wim@iguana.be>
diff --git a/drivers/watchdog/imgpdc_wdt.c b/drivers/watchdog/imgpdc_wdt.c
@@ -191,6 +191,7 @@ static int pdc_wdt_probe(struct platform_device *pdev)
 	pdc_wdt->wdt_dev.ops = &pdc_wdt_ops;
 	pdc_wdt->wdt_dev.max_timeout = 1 << PDC_WDT_CONFIG_DELAY_MASK;
 	pdc_wdt->wdt_dev.parent = &pdev->dev;
+	watchdog_set_drvdata(&pdc_wdt->wdt_dev, pdc_wdt);
 
 	ret = watchdog_init_timeout(&pdc_wdt->wdt_dev, heartbeat, &pdev->dev);
 	if (ret < 0) {
@@ -232,7 +233,6 @@ static int pdc_wdt_probe(struct platform_device *pdev)
 	watchdog_set_nowayout(&pdc_wdt->wdt_dev, nowayout);
 
 	platform_set_drvdata(pdev, pdc_wdt);
-	watchdog_set_drvdata(&pdc_wdt->wdt_dev, pdc_wdt);
 
 	ret = watchdog_register_device(&pdc_wdt->wdt_dev);
 	if (ret)
