On Monday, August 22, 2011, Tejun Heo wrote: > Hello, Rafael. > > On Sun, Aug 21, 2011 at 08:03:14PM +0200, Rafael J. Wysocki wrote: > > From: Rafael J. Wysocki <rjw@xxxxxxx> > > Subject: PM / Freezer: Move might_sleep() from try_to_freeze() > > > > There are some code paths that call try_to_freeze() from interrupt > > context, but doing so they know that the current process cannot > > possible be freezing (e.g. during reboot on ARM). However, the > > recently added might_sleep() annotation in try_to_freeze() > > triggers in those cases, making it look like there were bugs in > > those places, which really isn't the case. > > > > Therefore move might_sleep() from try_to_freeze() to > > __refrigerator() so that it doesn't produce false positives. > > Hmmm... I can't quite agree with this change. Some invocations of > try_to_freeze() can be very difficult to trigger. Freezing isn't a > frequent operation after some try_to_freeze() can be buried in weird > places. might_sleep() is exactly to detect context bugs in these > situations. If a code path is called from both sleepable and > unsleepable context and it knows that the latter wouldn't happen if > the system is freezing, that code path should conditionalize > invocation of try_to_freeze() based on its knowledge of context. That > way, all other normal cases get the might_sleep() protection and the > peculiar logic in that code path is explicitly described - win win. > > Can you please point me to where the problem was? Apparently, during reboot on ARM try_to_freeze() is called via do_signal() with interrupts disabled. Thanks, Rafael _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
