4.18-stable review patch. If anyone has any objections, please let me know.
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From: Alexandre Belloni alexandre.belloni@bootlin.com
[ Upstream commit 9612f8f503804d2fd2f63aa6ba1e58bba4612d96 ]
The IRQ work is added 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 calling menelaus_add_irq_work.
Also, this solves a possible leak as the RTC is never released.
Signed-off-by: Alexandre Belloni alexandre.belloni@bootlin.com Signed-off-by: Lee Jones lee.jones@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/mfd/menelaus.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-)
--- a/drivers/mfd/menelaus.c +++ b/drivers/mfd/menelaus.c @@ -1094,6 +1094,7 @@ static void menelaus_rtc_alarm_work(stru static inline void menelaus_rtc_init(struct menelaus_chip *m) { int alarm = (m->client->irq > 0); + int err;
/* assume 32KDETEN pin is pulled high */ if (!(menelaus_read_reg(MENELAUS_OSC_CTRL) & 0x80)) { @@ -1101,6 +1102,12 @@ static inline void menelaus_rtc_init(str return; }
+ m->rtc = devm_rtc_allocate_device(&m->client->dev); + if (IS_ERR(m->rtc)) + return; + + m->rtc->ops = &menelaus_rtc_ops; + /* support RTC alarm; it can issue wakeups */ if (alarm) { if (menelaus_add_irq_work(MENELAUS_RTCALM_IRQ, @@ -1125,10 +1132,8 @@ static inline void menelaus_rtc_init(str menelaus_write_reg(MENELAUS_RTC_CTRL, m->rtc_control); }
- m->rtc = rtc_device_register(DRIVER_NAME, - &m->client->dev, - &menelaus_rtc_ops, THIS_MODULE); - if (IS_ERR(m->rtc)) { + err = rtc_register_device(m->rtc); + if (err) { if (alarm) { menelaus_remove_irq_work(MENELAUS_RTCALM_IRQ); device_init_wakeup(&m->client->dev, 0);