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author | Victor Ding <victording@google.com> | 2020-08-14 11:17:30 +0200 |
---|---|---|
committer | Alexandre Belloni <alexandre.belloni@bootlin.com> | 2020-08-21 00:10:33 +0200 |
commit | c254bcd7231a3eeafc453f6ee3a483a2e7ff486e (patch) | |
tree | 7f0529705333f96e197e6f23da322bc751f2af26 /drivers/rtc/rtc-cmos.c | |
parent | Linux 5.9-rc1 (diff) | |
download | linux-c254bcd7231a3eeafc453f6ee3a483a2e7ff486e.tar.xz linux-c254bcd7231a3eeafc453f6ee3a483a2e7ff486e.zip |
rtc: cmos: zero-init wkalrm when reading from CMOS
cmos_read_alarm() may leave certain fields of a struct rtc_wkalrm
untouched; therefore, these fields contain garbage if not properly
initialized, leading to inconsistent values when converting into
time64_t. This patch to zero initialize the struct before calling
cmos_read_alarm().
Note that this patch is not intended to produce a correct time64_t, it
is only to produce a consistent value. In the case of suspend/resume, a
correct time64_t is not necessary; a consistent value is sufficient to
correctly perform an equality test for t_current_expires and
t_saved_expires. Logic to deduce a correct time64_t is expensive and
hence should be avoided.
Signed-off-by: Victor Ding <victording@google.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20200814191654.v2.1.Iaf7638a2f2a87ff68d85fcb8dec615e41340c97f@changeid
Diffstat (limited to 'drivers/rtc/rtc-cmos.c')
-rw-r--r-- | drivers/rtc/rtc-cmos.c | 2 |
1 files changed, 2 insertions, 0 deletions
diff --git a/drivers/rtc/rtc-cmos.c b/drivers/rtc/rtc-cmos.c index bcc96ab7793f..c633319cdb91 100644 --- a/drivers/rtc/rtc-cmos.c +++ b/drivers/rtc/rtc-cmos.c @@ -1006,6 +1006,7 @@ static int cmos_suspend(struct device *dev) enable_irq_wake(cmos->irq); } + memset(&cmos->saved_wkalrm, 0, sizeof(struct rtc_wkalrm)); cmos_read_alarm(dev, &cmos->saved_wkalrm); dev_dbg(dev, "suspend%s, ctrl %02x\n", @@ -1054,6 +1055,7 @@ static void cmos_check_wkalrm(struct device *dev) return; } + memset(¤t_alarm, 0, sizeof(struct rtc_wkalrm)); cmos_read_alarm(dev, ¤t_alarm); t_current_expires = rtc_tm_to_time64(¤t_alarm.time); t_saved_expires = rtc_tm_to_time64(&cmos->saved_wkalrm.time); |