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| author |   Alexandre Belloni <alexandre.belloni@bootlin.com> | 2018-05-17 22:47:05 +0200 |
|---|---|---|
| committer | Alexandre Belloni <alexandre.belloni@bootlin.com> | 2018-05-17 22:54:19 +0200 |
| commit | 9a99247c9c1d1c95c6e8153d013979aac6111c6e (patch) | |
| tree | 6b4b17e2938b65b13741360d4465b3db146e5b0d /drivers/rtc | |
| parent | rtc: rx8581: switch to regmap (diff) | |
| download | linux-dev-9a99247c9c1d1c95c6e8153d013979aac6111c6e.tar.xz linux-dev-9a99247c9c1d1c95c6e8153d013979aac6111c6e.zip | |
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')
| -rw-r--r-- | drivers/rtc/rtc-vr41xx.c | 9 |
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: |