tree 7f0529705333f96e197e6f23da322bc751f2af26
parent 9123e3a74ec7b934a4a099e98af6a61c2f80bbf5
author Victor Ding <victording@google.com> 1597396650 +1000
committer Alexandre Belloni <alexandre.belloni@bootlin.com> 1597961433 +0200

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