iv/linux
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases Wiki Activity

rtc: mc146818-lib: fix locking in mc146818_set_time

Browse Source 
[ Upstream commit 811f5559270f25c34c338d6eaa2ece2544c3d3bd ]

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
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Mateusz Jończyk 2022-02-20 10:04:03 +01:00 committed by Greg Kroah-Hartman
parent 5e26531d81
commit 5c432383b6
1 changed files with 4 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

6
drivers/rtc/rtc-mc146818-lib.c
View File

@ -283,8 +283,10 @@ 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);