diff options
| author | Chen Yu <yu.c.chen@intel.com> | 2016-11-28 14:35:19 -0800 |
|---|---|---|
| committer | Thomas Gleixner <tglx@linutronix.de> | 2016-11-29 18:02:58 +0100 |
| commit | ba58d1020a54933c6b087a3107661c8513556cb8 (patch) | |
| tree | 1bb61c0113f26bbbd4308a5040904bdf8fa3eebc /arch/x86/kernel/rtc.c | |
| parent | a109ded26c8c85c17872c8f61e8979c5d650004d (diff) | |
| download | linux-ba58d1020a54933c6b087a3107661c8513556cb8.tar.bz2 | |
timekeeping: Ignore the bogus sleep time if pm_trace is enabled
Power management suspend/resume tracing (ab)uses the RTC to store
suspend/resume information persistently. As a consequence the RTC value is
clobbered when timekeeping is resumed and tries to inject the sleep time.
Commit a4f8f6667f09 ("timekeeping: Cap array access in timekeeping_debug")
plugged a out of bounds array access in the timekeeping debug code which
was caused by the clobbered RTC value, but we still use the clobbered RTC
value for sleep time injection into kernel timekeeping, which will result
in random adjustments depending on the stored "hash" value.
To prevent this keep track of the RTC clobbering and ignore the invalid RTC
timestamp at resume. If the system resumed successfully clear the flag,
which marks the RTC as unusable, warn the user about the RTC clobber and
recommend to adjust the RTC with 'ntpdate' or 'rdate'.
[jstultz: Fixed up pr_warn formating, and implemented suggestions from Ingo]
[ tglx: Rewrote changelog ]
Originally-from: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Chen Yu <yu.c.chen@intel.com>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Acked-by: Pavel Machek <pavel@ucw.cz>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Prarit Bhargava <prarit@redhat.com>
Cc: "Rafael J. Wysocki" <rjw@rjwysocki.net>
Cc: Richard Cochran <richardcochran@gmail.com>
Cc: Xunlei Pang <xlpang@redhat.com>
Cc: Len Brown <lenb@kernel.org>
Link: http://lkml.kernel.org/r/1480372524-15181-3-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Diffstat (limited to 'arch/x86/kernel/rtc.c')
| -rw-r--r-- | arch/x86/kernel/rtc.c | 9 |
1 files changed, 9 insertions, 0 deletions
diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c index 79c6311cd912..5b21cb7d84d6 100644 --- a/arch/x86/kernel/rtc.c +++ b/arch/x86/kernel/rtc.c @@ -64,6 +64,15 @@ void mach_get_cmos_time(struct timespec *now) unsigned int status, year, mon, day, hour, min, sec, century = 0; unsigned long flags; + /* + * If pm_trace abused the RTC as storage, set the timespec to 0, + * which tells the caller that this RTC value is unusable. + */ + if (!pm_trace_rtc_valid()) { + now->tv_sec = now->tv_nsec = 0; + return; + } + spin_lock_irqsave(&rtc_lock, flags); /* |