[PATCH 1/2] rtc: st-lpc: fix possible race condition
From: Alexandre Belloni <alexandre.belloni@bootlin.com>
Date: 2018-05-20 12:33:54
Also in:
linux-arm-kernel, lkml
Subsystem:
arm/sti architecture, real time clock (rtc) subsystem, the rest · Maintainers:
Patrice Chotard, Alexandre Belloni, Linus Torvalds
The IRQ is requested before the struct rtc is allocated and registered, but this struct is used in the IRQ handler. This may lead to a NULL pointer dereference. Switch to devm_rtc_allocate_device/rtc_register_device to allocate the rtc before requesting the IRQ. Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> --- drivers/rtc/rtc-st-lpc.c | 24 +++++++++--------------- 1 file changed, 9 insertions(+), 15 deletions(-)
diff --git a/drivers/rtc/rtc-st-lpc.c b/drivers/rtc/rtc-st-lpc.c
index d5222667f892..2f1ef2c28740 100644
--- a/drivers/rtc/rtc-st-lpc.c
+++ b/drivers/rtc/rtc-st-lpc.c@@ -212,6 +212,10 @@ static int st_rtc_probe(struct platform_device *pdev) if (!rtc) return -ENOMEM; + rtc->rtc_dev = devm_rtc_allocate_device(&pdev->dev); + if (IS_ERR(rtc->rtc_dev)) + return PTR_ERR(rtc->rtc_dev); + spin_lock_init(&rtc->lock); res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
@@ -253,26 +257,17 @@ static int st_rtc_probe(struct platform_device *pdev) platform_set_drvdata(pdev, rtc); - rtc->rtc_dev = rtc_device_register("st-lpc-rtc", &pdev->dev, - &st_rtc_ops, THIS_MODULE); - if (IS_ERR(rtc->rtc_dev)) { + rtc->rtc_dev->ops = &st_rtc_ops; + + ret = rtc_register_device(rtc->rtc_dev); + if (ret) { clk_disable_unprepare(rtc->clk); - return PTR_ERR(rtc->rtc_dev); + return ret; } return 0; } -static int st_rtc_remove(struct platform_device *pdev) -{ - struct st_rtc *rtc = platform_get_drvdata(pdev); - - if (likely(rtc->rtc_dev)) - rtc_device_unregister(rtc->rtc_dev); - - return 0; -} - #ifdef CONFIG_PM_SLEEP static int st_rtc_suspend(struct device *dev) {
@@ -325,7 +320,6 @@ static struct platform_driver st_rtc_platform_driver = { .of_match_table = st_rtc_match, }, .probe = st_rtc_probe, - .remove = st_rtc_remove, }; module_platform_driver(st_rtc_platform_driver);
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2.17.0