From bcdd559268039d8340d38fa58668393596e29fdc Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Mon, 12 Feb 2018 23:47:49 +0100 Subject: rtc: rp5c01: 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 --- drivers/rtc/rtc-rp5c01.c | 12 ++++++++++-- 1 file changed, 10 insertions(+), 2 deletions(-) (limited to 'drivers/rtc/rtc-rp5c01.c') diff --git a/drivers/rtc/rtc-rp5c01.c b/drivers/rtc/rtc-rp5c01.c index 026035373ae6..38a12435b5a0 100644 --- a/drivers/rtc/rtc-rp5c01.c +++ b/drivers/rtc/rtc-rp5c01.c @@ -249,16 +249,24 @@ static int __init rp5c01_rtc_probe(struct platform_device *dev) platform_set_drvdata(dev, priv); - rtc = devm_rtc_device_register(&dev->dev, "rtc-rp5c01", &rp5c01_rtc_ops, - THIS_MODULE); + rtc = devm_rtc_allocate_device(&dev->dev); if (IS_ERR(rtc)) return PTR_ERR(rtc); + + rtc->ops = &rp5c01_rtc_ops; + priv->rtc = rtc; error = sysfs_create_bin_file(&dev->dev.kobj, &priv->nvram_attr); if (error) return error; + error = rtc_register_device(rtc); + if (error) { + sysfs_remove_bin_file(&dev->dev.kobj, &priv->nvram_attr); + return error; + } + return 0; } -- cgit v1.2.3