| Message ID | 20220220090403.153928-1-mat.jonczyk@o2.pl |
|---|---|
| State | Accepted |
| Commit | 811f5559270f25c34c338d6eaa2ece2544c3d3bd |
| Headers | show |
| Series | rtc-mc146818-lib: fix locking in mc146818_set_time | expand |
On Sun, 20 Feb 2022 10:04:03 +0100, Mateusz Jończyk wrote: > In mc146818_set_time(), CMOS_READ(RTC_CONTROL) was performed without the > rtc_lock taken, which is required for CMOS accesses. Fix this. > > Nothing in kernel modifies RTC_DM_BINARY, so a separate critical section > is allowed here. > > > [...] Applied, thanks! [1/1] rtc-mc146818-lib: fix locking in mc146818_set_time commit: c63cdb340a7e0bd3734f9f8e27f082a054b45887 Best regards,
diff --git a/drivers/rtc/rtc-mc146818-lib.c b/drivers/rtc/rtc-mc146818-lib.c index ae9f131b43c0..562f99b664a2 100644 --- a/drivers/rtc/rtc-mc146818-lib.c +++ b/drivers/rtc/rtc-mc146818-lib.c @@ -232,8 +232,10 @@ int mc146818_set_time(struct rtc_time *time) if (yrs >= 100) yrs -= 100; - if (!(CMOS_READ(RTC_CONTROL) & RTC_DM_BINARY) - || RTC_ALWAYS_BCD) { + spin_lock_irqsave(&rtc_lock, flags); + save_control = CMOS_READ(RTC_CONTROL); + spin_unlock_irqrestore(&rtc_lock, flags); + if (!(save_control & RTC_DM_BINARY) || RTC_ALWAYS_BCD) { sec = bin2bcd(sec); min = bin2bcd(min); hrs = bin2bcd(hrs);
In mc146818_set_time(), CMOS_READ(RTC_CONTROL) was performed without the rtc_lock taken, which is required for CMOS accesses. Fix this. Nothing in kernel modifies RTC_DM_BINARY, so a separate critical section is allowed here. Fixes: dcf257e92622 ("rtc: mc146818: Reduce spinlock section in mc146818_set_time()") Signed-off-by: Mateusz Jończyk <mat.jonczyk@o2.pl> Cc: Alessandro Zummo <a.zummo@towertech.it> Cc: Alexandre Belloni <alexandre.belloni@bootlin.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: stable@vger.kernel.org --- drivers/rtc/rtc-mc146818-lib.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-) base-commit: 754e0b0e35608ed5206d6a67a791563c631cec07