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rtc: mc146818-lib: fix locking in mc146818_set_time 

ANBZ: #9626

commit 811f555927 upstream

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: dcf257e926 ("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
Signed-off-by: Guanjun <guanjun@linux.alibaba.com>
Reviewed-by: Artie Ding <artie.ding@linux.alibaba.com>
Reviewed-by: Guixin Liu <kanie@linux.alibaba.com>
Link: https://gitee.com/anolis/cloud-kernel/pulls/3591
This commit is contained in:
Mateusz Jończyk 2022-02-20 10:04:03 +01:00 committed by 小龙
parent 150f430298
commit 7e90ea1331
1 changed files with 4 additions and 2 deletions
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6
drivers/rtc/rtc-mc146818-lib.c
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@ -197,8 +197,10 @@ 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);