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authorMateusz Jończyk <mat.jonczyk@o2.pl>2022-02-20 10:04:03 +0100
committerAlexandre Belloni <alexandre.belloni@bootlin.com>2022-03-23 19:58:37 +0100
commit811f5559270f25c34c338d6eaa2ece2544c3d3bd (patch)
tree1412309dcbdd4f866da1c07d69cd031483740472 /drivers/rtc
parenteb74f47bb6b0c0494d7c90491ee321f3b699f93f (diff)
rtc: mc146818-lib: fix locking in mc146818_set_time
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 Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com> Link: https://lore.kernel.org/r/20220220090403.153928-1-mat.jonczyk@o2.pl
Diffstat (limited to 'drivers/rtc')
-rw-r--r--drivers/rtc/rtc-mc146818-lib.c6
1 files changed, 4 insertions, 2 deletions
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);