From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: From: Andrew Bresticker To: Wim Van Sebroeck , Guenter Roeck Cc: linux-watchdog@vger.kernel.org, linux-kernel@vger.kernel.org, Naidu Tellapati , Andrew Bresticker , Ezequiel Garcia Subject: [PATCH 1/4] watchdog: imgpdc: Fix NULL pointer dereference on probe Date: Tue, 31 Mar 2015 11:49:08 -0700 Message-Id: <1427827751-19705-1-git-send-email-abrestic@chromium.org> List-ID: From: Naidu Tellapati pdc_wdt_probe() called pdc_wdt_stop() before watchdog_set_drvdata(), resulting in the following NULL pointer dereference: CPU 0 Unable to handle kernel paging request at virtual address 0000008c, epc == 8082a2b8, ra == 8082a914 Oops[#1]: CPU: 0 PID: 1 Comm: swapper/0 Not tainted 4.0.0-rc5+ #102 task: 8f8c0000 ti: 8f89e000 task.ti: 8f89e000 $ 0 : 00000000 8082a914 00000000 dc8ba200 $ 4 : 8faf9418 80ac0000 8f9cdc10 00008012 $ 8 : 00000000 806e2350 00000001 8f001880 $12 : 8f89fd14 00000000 00000000 65646f4d $16 : 8faf9418 8f9cdc10 8f001880 8f9cdc00 $20 : 00000000 80c20000 00000000 80bc0000 $24 : 00000002 00000000 $28 : 8f89e000 8f89fd00 00000000 8082a914 Hi : 0000006b Lo : 00008013 epc : 8082a2b8 pdc_wdt_stop+0x1c/0x44 Not tainted ra : 8082a914 pdc_wdt_probe+0x404/0x550 Status: 11000403 KERNEL EXL IE Cause : 00800008 BadVA : 0000008c PrId : 0001a120 (MIPS interAptiv (multi)) Fix it by moving the call to pdc_wdt_stop() after we've set drvdata. Signed-off-by: Naidu Tellapati Signed-off-by: Andrew Bresticker Cc: Ezequiel Garcia --- drivers/watchdog/imgpdc_wdt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/watchdog/imgpdc_wdt.c b/drivers/watchdog/imgpdc_wdt.c index c8def68..c4151cd 100644 --- a/drivers/watchdog/imgpdc_wdt.c +++ b/drivers/watchdog/imgpdc_wdt.c @@ -199,8 +199,6 @@ static int pdc_wdt_probe(struct platform_device *pdev) "Initial timeout out of range! setting max timeout\n"); } - pdc_wdt_stop(&pdc_wdt->wdt_dev); - /* Find what caused the last reset */ val = readl(pdc_wdt->base + PDC_WDT_TICKLE1); val = (val & PDC_WDT_TICKLE_STATUS_MASK) >> PDC_WDT_TICKLE_STATUS_SHIFT; @@ -234,6 +232,8 @@ static int pdc_wdt_probe(struct platform_device *pdev) platform_set_drvdata(pdev, pdc_wdt); watchdog_set_drvdata(&pdc_wdt->wdt_dev, pdc_wdt); + pdc_wdt_stop(&pdc_wdt->wdt_dev); + ret = watchdog_register_device(&pdc_wdt->wdt_dev); if (ret) goto disable_wdt_clk; -- 2.2.0.rc0.207.ga3a616c