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| author | Mateusz Jończyk <mat.jonczyk@o2.pl> | 2022-02-20 12:04:03 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2022-04-08 15:22:56 +0300 |
| commit | 8e167fdd4f625572666b566fd29e8ef79566fece (patch) | |
| tree | 4436fc1c26c487ab3eff586d651cde3294d4b638 /drivers/rtc | |
| parent | 0cc320929ac6a2e696ee61122dfb9147872bcebf (diff) | |
| download | linux-8e167fdd4f625572666b566fd29e8ef79566fece.tar.xz | |
rtc: mc146818-lib: fix locking in mc146818_set_time
commit 811f5559270f25c34c338d6eaa2ece2544c3d3bd 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: 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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/rtc')
| -rw-r--r-- | drivers/rtc/rtc-mc146818-lib.c | 6 |
1 files changed, 4 insertions, 2 deletions
diff --git a/drivers/rtc/rtc-mc146818-lib.c b/drivers/rtc/rtc-mc146818-lib.c index 2065842f775d..04b05e3b68cb 100644 --- a/drivers/rtc/rtc-mc146818-lib.c +++ b/drivers/rtc/rtc-mc146818-lib.c @@ -176,8 +176,10 @@ 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); |