Previously we encountered some memory overflow issues due to the bogus sleep time brought by inconsistent rtc, which is triggered when pm_trace is enabled, please refer to: https://patchwork.kernel.org/patch/9286365/ It's improper in the first place to call __timekeeping_inject_sleeptime() in case that pm_trace is enabled simply because that "hash" time value will wreckage the timekeeping subsystem.
So this patch ignores the sleep time if pm_trace is enabled in the following situation: 1. rtc is used as persist clock to compensate for sleep time, (because system does not have a nonstop clocksource) or 2. rtc is used to calculate the sleep time in rtc_resume. Cc: Rafael J. Wysocki <[email protected]> Cc: John Stultz <[email protected]> Cc: Thomas Gleixner <[email protected]> Cc: Xunlei Pang <[email protected]> Cc: Zhang Rui <[email protected]> Cc: [email protected] Cc: [email protected] Suggested-by: Rafael J. Wysocki <[email protected]> Reported-by: Janek Kozicki <[email protected]> Signed-off-by: Chen Yu <[email protected]> --- arch/x86/kernel/rtc.c | 7 +++++++ kernel/time/timekeeping.c | 14 +++++++++++++- 2 files changed, 20 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/rtc.c b/arch/x86/kernel/rtc.c index 79c6311c..6039138 100644 --- a/arch/x86/kernel/rtc.c +++ b/arch/x86/kernel/rtc.c @@ -8,6 +8,7 @@ #include <linux/export.h> #include <linux/pnp.h> #include <linux/of.h> +#include <linux/pm-trace.h> #include <asm/vsyscall.h> #include <asm/x86_init.h> @@ -146,6 +147,12 @@ void read_persistent_clock(struct timespec *ts) x86_platform.get_wallclock(ts); } +bool persistent_clock_is_usable(void) +{ + /* Unusable if pm_trace is enabled. */ + return !((x86_platform.get_wallclock == mach_get_cmos_time) && + pm_trace_is_enabled()); +} static struct resource rtc_resources[] = { [0] = { diff --git a/kernel/time/timekeeping.c b/kernel/time/timekeeping.c index 3b65746..3122bd2b 100644 --- a/kernel/time/timekeeping.c +++ b/kernel/time/timekeeping.c @@ -23,6 +23,7 @@ #include <linux/stop_machine.h> #include <linux/pvclock_gtod.h> #include <linux/compiler.h> +#include <linux/pm-trace.h> #include "tick-internal.h" #include "ntp_internal.h" @@ -1450,6 +1451,11 @@ void __weak read_boot_clock64(struct timespec64 *ts) ts->tv_nsec = 0; } +bool __weak persistent_clock_is_usable(void) +{ + return true; +} + /* Flag for if timekeeping_resume() has injected sleeptime */ static bool sleeptime_injected; @@ -1551,7 +1557,7 @@ static void __timekeeping_inject_sleeptime(struct timekeeper *tk, */ bool timekeeping_rtc_skipresume(void) { - return sleeptime_injected; + return sleeptime_injected || pm_trace_is_enabled(); } /** @@ -1662,6 +1668,12 @@ void timekeeping_resume(void) } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) { ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time); sleeptime_injected = true; + /* + * If rtc is used as persist clock thus it + * would be bogus when pm_trace is enabled. + */ + if (!persistent_clock_is_usable()) + sleeptime_injected = false; } if (sleeptime_injected) -- 2.7.4
