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authorAlexandre Belloni <alexandre.belloni@bootlin.com>2018-02-21 13:57:05 +0300
committerAlexandre Belloni <alexandre.belloni@bootlin.com>2018-03-17 16:20:42 +0300
commit201fac95e799c3d0304ec724d555e1251b9f6e84 (patch)
tree1b6758467df034e9207fe9a083faabaccb3bda5e /drivers/rtc/rtc-rk808.c
parent4cda172bc338abf770dcdbcf61049ef0d76b17fc (diff)
downloadlinux-201fac95e799c3d0304ec724d555e1251b9f6e84.tar.xz
rtc: rk808: fix possible race condition
The probe function is not allowed to fail after registering the RTC because the following may happen: CPU0: CPU1: sys_load_module() do_init_module() do_one_initcall() cmos_do_probe() rtc_device_register() __register_chrdev() cdev->owner = struct module* open("/dev/rtc0") rtc_device_unregister() module_put() free_module() module_free(mod->module_core) /* struct module *module is now freed */ chrdev_open() spin_lock(cdev_lock) cdev_get() try_module_get() module_is_live() /* dereferences already freed struct module* */ Switch to devm_rtc_allocate_device/rtc_register_device to register the rtc as late as possible. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Diffstat (limited to 'drivers/rtc/rtc-rk808.c')
-rw-r--r--drivers/rtc/rtc-rk808.c14
1 files changed, 7 insertions, 7 deletions
diff --git a/drivers/rtc/rtc-rk808.c b/drivers/rtc/rtc-rk808.c
index e40f35d1ced3..739c0d42e835 100644
--- a/drivers/rtc/rtc-rk808.c
+++ b/drivers/rtc/rtc-rk808.c
@@ -405,12 +405,11 @@ static int rk808_rtc_probe(struct platform_device *pdev)
device_init_wakeup(&pdev->dev, 1);
- rk808_rtc->rtc = devm_rtc_device_register(&pdev->dev, "rk808-rtc",
- &rk808_rtc_ops, THIS_MODULE);
- if (IS_ERR(rk808_rtc->rtc)) {
- ret = PTR_ERR(rk808_rtc->rtc);
- return ret;
- }
+ rk808_rtc->rtc = devm_rtc_allocate_device(&pdev->dev);
+ if (IS_ERR(rk808_rtc->rtc))
+ return PTR_ERR(rk808_rtc->rtc);
+
+ rk808_rtc->rtc->ops = &rk808_rtc_ops;
rk808_rtc->irq = platform_get_irq(pdev, 0);
if (rk808_rtc->irq < 0) {
@@ -427,9 +426,10 @@ static int rk808_rtc_probe(struct platform_device *pdev)
if (ret) {
dev_err(&pdev->dev, "Failed to request alarm IRQ %d: %d\n",
rk808_rtc->irq, ret);
+ return ret;
}
- return ret;
+ return rtc_register_device(rk808_rtc->rtc);
}
static struct platform_driver rk808_rtc_driver = {