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authorAlexandre Belloni <alexandre.belloni@bootlin.com>2018-05-17 23:47:05 +0300
committerAlexandre Belloni <alexandre.belloni@bootlin.com>2018-05-17 23:54:19 +0300
commit9a99247c9c1d1c95c6e8153d013979aac6111c6e (patch)
tree6b4b17e2938b65b13741360d4465b3db146e5b0d /drivers/rtc/rtc-vr41xx.c
parent94389b28ba6c03eecf45105026c1f9978481a706 (diff)
downloadlinux-9a99247c9c1d1c95c6e8153d013979aac6111c6e.tar.xz
rtc: vr41xx: fix possible race condition
The probe function is not allowed to fail after the RTC is registered 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* */ Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Diffstat (limited to 'drivers/rtc/rtc-vr41xx.c')
-rw-r--r--drivers/rtc/rtc-vr41xx.c9
1 files changed, 7 insertions, 2 deletions
diff --git a/drivers/rtc/rtc-vr41xx.c b/drivers/rtc/rtc-vr41xx.c
index 480cffe8d321..2f1212a25f7e 100644
--- a/drivers/rtc/rtc-vr41xx.c
+++ b/drivers/rtc/rtc-vr41xx.c
@@ -292,13 +292,14 @@ static int rtc_probe(struct platform_device *pdev)
goto err_rtc1_iounmap;
}
- rtc = devm_rtc_device_register(&pdev->dev, rtc_name, &vr41xx_rtc_ops,
- THIS_MODULE);
+ rtc = devm_rtc_allocate_device(&pdev->dev);
if (IS_ERR(rtc)) {
retval = PTR_ERR(rtc);
goto err_iounmap_all;
}
+ rtc->ops = &vr41xx_rtc_ops;
+
rtc->max_user_freq = MAX_PERIODIC_RATE;
spin_lock_irq(&rtc_lock);
@@ -340,6 +341,10 @@ static int rtc_probe(struct platform_device *pdev)
dev_info(&pdev->dev, "Real Time Clock of NEC VR4100 series\n");
+ retval = rtc_register_device(rtc);
+ if (retval)
+ goto err_iounmap_all;
+
return 0;
err_iounmap_all: