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023d377914
The memory barrier in wakeup_source_deactivate() is supposed to prevent the callers of pm_wakeup_pending() and pm_get_wakeup_count() from seeing the new value of events_in_progress (0, in particular) and the old value of event_count at the same time. However, if wakeup_source_deactivate() is executed by CPU0 and, for instance, pm_wakeup_pending() is executed by CPU1, where both processors can reorder operations, the memory barrier in wakeup_source_deactivate() doesn't affect CPU1 which can reorder reads. In that case CPU1 may very well decide to fetch event_count before it's modified and events_in_progress after it's been updated, so pm_wakeup_pending() may fail to detect a wakeup event. This issue can be addressed by using a single atomic variable to store both events_in_progress and event_count, so that they can be updated together in a single atomic operation. Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl> |
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| .. | ||
| generic_ops.c | ||
| main.c | ||
| Makefile | ||
| opp.c | ||
| power.h | ||
| runtime.c | ||
| sysfs.c | ||
| trace.c | ||
| wakeup.c | ||