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author | Vaibhav Jain <vaibhav@linux.vnet.ibm.com> | 2017-05-19 22:18:55 +0530 |
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committer | Alexandre Belloni <alexandre.belloni@free-electrons.com> | 2017-05-31 13:04:54 +0200 |
commit | da96aea0ed177105cb13ee83b328f6c61e061d3f (patch) | |
tree | a0f140bd6f0d3c6853e2b2f4b7390521d5083eef /Documentation/rtc.txt | |
parent | 6dc1cf6f932bb0ea4d8f5e913a0a401ecacd2f03 (diff) | |
download | linux-da96aea0ed177105cb13ee83b328f6c61e061d3f.tar.bz2 |
rtc: interface: Validate alarm-time before handling rollover
In function __rtc_read_alarm() its possible for an alarm time-stamp to
be invalid even after replacing missing components with current
time-stamp. The condition 'alarm->time.tm_year < 70' will trigger this
case and will cause the call to 'rtc_tm_to_time64(&alarm->time)'
return a negative value for variable t_alm.
While handling alarm rollover this negative t_alm (assumed to seconds
offset from '1970-01-01 00:00:00') is converted back to rtc_time via
rtc_time64_to_tm() which results in this error log with seemingly
garbage values:
"rtc rtc0: invalid alarm value: -2-1--1041528741
2005511117:71582844:32"
This error was generated when the rtc driver (rtc-opal in this case)
returned an alarm time-stamp of '00-00-00 00:00:00' to indicate that
the alarm is disabled. Though I have submitted a separate fix for the
rtc-opal driver, this issue may potentially impact other
existing/future rtc drivers.
To fix this issue the patch validates the alarm time-stamp just after
filling up the missing datetime components and if rtc_valid_tm() still
reports it to be invalid then bails out of the function without
handling the rollover.
Reported-by: Steve Best <sbest@redhat.com>
Signed-off-by: Vaibhav Jain <vaibhav@linux.vnet.ibm.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Diffstat (limited to 'Documentation/rtc.txt')
0 files changed, 0 insertions, 0 deletions