[PATCH 2/3] rtc: pl030: fix possible race condition
From: alexandre.belloni@bootlin.com (Alexandre Belloni)
Date: 2018-09-09 20:39:08
Also in:
linux-mediatek, linux-rtc, lkml
Subsystem:
real time clock (rtc) subsystem, the rest · Maintainers:
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-pl030.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-)
diff --git a/drivers/rtc/rtc-pl030.c b/drivers/rtc/rtc-pl030.c
index f85a1a93e669..343bb6ed1783 100644
--- a/drivers/rtc/rtc-pl030.c
+++ b/drivers/rtc/rtc-pl030.c@@ -112,6 +112,13 @@ static int pl030_probe(struct amba_device *dev, const struct amba_id *id) goto err_rtc; } + rtc->rtc = devm_rtc_allocate_device(&dev->dev); + if (IS_ERR(rtc->rtc)) { + ret = PTR_ERR(rtc->rtc); + goto err_rtc; + } + + rtc->rtc->ops = &pl030_ops; rtc->base = ioremap(dev->res.start, resource_size(&dev->res)); if (!rtc->base) { ret = -ENOMEM;
@@ -128,12 +135,9 @@ static int pl030_probe(struct amba_device *dev, const struct amba_id *id) if (ret) goto err_irq; - rtc->rtc = rtc_device_register("pl030", &dev->dev, &pl030_ops, - THIS_MODULE); - if (IS_ERR(rtc->rtc)) { - ret = PTR_ERR(rtc->rtc); + ret = rtc_register_device(rtc->rtc); + if (ret) goto err_reg; - } return 0;
@@ -154,7 +158,6 @@ static int pl030_remove(struct amba_device *dev) writel(0, rtc->base + RTC_CR); free_irq(dev->irq[0], rtc); - rtc_device_unregister(rtc->rtc); iounmap(rtc->base); amba_release_regions(dev);
--
2.19.0.rc2