From 6330c7070be6783b82025d2bc259db8413c00182 Mon Sep 17 00:00:00 2001 From: Sachin Kamat Date: Mon, 4 Mar 2013 10:36:41 +0530 Subject: [PATCH 1/2] watchdog: Convert to devm_ioremap_resource() Use the newly introduced devm_ioremap_resource() instead of devm_request_and_ioremap() which provides more consistent error handling. devm_ioremap_resource() provides its own error messages; so all explicit error messages can be removed from the failure code paths. Signed-off-by: Sachin Kamat Reviewed-by: Thierry Reding Cc: Gabor Juhos Cc: Paul Mundt Signed-off-by: Wim Van Sebroeck --- drivers/watchdog/ath79_wdt.c | 8 +++----- drivers/watchdog/davinci_wdt.c | 9 ++++----- drivers/watchdog/s3c2410_wdt.c | 7 +++---- drivers/watchdog/shwdt.c | 7 ++++--- 4 files changed, 14 insertions(+), 17 deletions(-) diff --git a/drivers/watchdog/ath79_wdt.c b/drivers/watchdog/ath79_wdt.c index 898799074a13..d184c48a0482 100644 --- a/drivers/watchdog/ath79_wdt.c +++ b/drivers/watchdog/ath79_wdt.c @@ -253,11 +253,9 @@ static int ath79_wdt_probe(struct platform_device *pdev) return -EINVAL; } - wdt_base = devm_request_and_ioremap(&pdev->dev, res); - if (!wdt_base) { - dev_err(&pdev->dev, "unable to remap memory region\n"); - return -ENOMEM; - } + wdt_base = devm_ioremap_resource(&pdev->dev, res); + if (IS_ERR(wdt_base)) + return PTR_ERR(wdt_base); wdt_clk = devm_clk_get(&pdev->dev, "wdt"); if (IS_ERR(wdt_clk)) diff --git a/drivers/watchdog/davinci_wdt.c b/drivers/watchdog/davinci_wdt.c index 7df1fdca9e78..100d4fbfde2a 100644 --- a/drivers/watchdog/davinci_wdt.c +++ b/drivers/watchdog/davinci_wdt.c @@ -27,6 +27,7 @@ #include #include #include +#include #define MODULE_NAME "DAVINCI-WDT: " @@ -221,11 +222,9 @@ static int davinci_wdt_probe(struct platform_device *pdev) return -ENOENT; } - wdt_base = devm_request_and_ioremap(dev, wdt_mem); - if (!wdt_base) { - dev_err(dev, "ioremap failed\n"); - return -EADDRNOTAVAIL; - } + wdt_base = devm_ioremap_resource(dev, wdt_mem); + if (IS_ERR(wdt_base)) + return PTR_ERR(wdt_base); ret = misc_register(&davinci_wdt_miscdev); if (ret < 0) { diff --git a/drivers/watchdog/s3c2410_wdt.c b/drivers/watchdog/s3c2410_wdt.c index c1a221cbeae4..ee03135f5abd 100644 --- a/drivers/watchdog/s3c2410_wdt.c +++ b/drivers/watchdog/s3c2410_wdt.c @@ -330,10 +330,9 @@ static int s3c2410wdt_probe(struct platform_device *pdev) } /* get the memory region for the watchdog timer */ - wdt_base = devm_request_and_ioremap(dev, wdt_mem); - if (wdt_base == NULL) { - dev_err(dev, "failed to devm_request_and_ioremap() region\n"); - ret = -ENOMEM; + wdt_base = devm_ioremap_resource(dev, wdt_mem); + if (IS_ERR(wdt_base)) { + ret = PTR_ERR(wdt_base); goto err; } diff --git a/drivers/watchdog/shwdt.c b/drivers/watchdog/shwdt.c index 6a89e4045fbd..6185af2b3310 100644 --- a/drivers/watchdog/shwdt.c +++ b/drivers/watchdog/shwdt.c @@ -34,6 +34,7 @@ #include #include #include +#include #include #define DRV_NAME "sh-wdt" @@ -249,9 +250,9 @@ static int sh_wdt_probe(struct platform_device *pdev) wdt->clk = NULL; } - wdt->base = devm_request_and_ioremap(wdt->dev, res); - if (unlikely(!wdt->base)) { - rc = -EADDRNOTAVAIL; + wdt->base = devm_ioremap_resource(wdt->dev, res); + if (IS_ERR(wdt->base)) { + rc = PTR_ERR(wdt->base); goto err; } From 60403f7a4d9368d187f79cba5e4672d01df37574 Mon Sep 17 00:00:00 2001 From: Guenter Roeck Date: Fri, 5 Apr 2013 21:22:43 -0700 Subject: [PATCH 2/2] watchdog: Fix race condition in registration code A race condition exists when registering the first watchdog device. Sequence of events: - watchdog_register_device calls watchdog_dev_register - watchdog_dev_register creates the watchdog misc device by calling misc_register. At that time, the matching character device (/dev/watchdog0) does not yet exist, and old_wdd is not set either. - Userspace gets an event and opens /dev/watchdog - watchdog_open is called and sets wdd = old_wdd, which is still NULL, and tries to dereference it. This causes the kernel to panic. Seen with systemd trying to open /dev/watchdog immediately after it was created. Reported-by: Arkadiusz Miskiewicz Signed-off-by: Guenter Roeck Tested-by: Arkadiusz Miskiewicz Signed-off-by: Wim Van Sebroeck --- drivers/watchdog/watchdog_dev.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/watchdog/watchdog_dev.c b/drivers/watchdog/watchdog_dev.c index 08b48bbf9f4b..faf4e189fe42 100644 --- a/drivers/watchdog/watchdog_dev.c +++ b/drivers/watchdog/watchdog_dev.c @@ -523,6 +523,7 @@ int watchdog_dev_register(struct watchdog_device *watchdog) int err, devno; if (watchdog->id == 0) { + old_wdd = watchdog; watchdog_miscdev.parent = watchdog->parent; err = misc_register(&watchdog_miscdev); if (err != 0) { @@ -531,9 +532,9 @@ int watchdog_dev_register(struct watchdog_device *watchdog) if (err == -EBUSY) pr_err("%s: a legacy watchdog module is probably present.\n", watchdog->info->identity); + old_wdd = NULL; return err; } - old_wdd = watchdog; } /* Fill in the data structures */