[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index] Re: [Xen-devel] [PATCH] fix locking in cpu_disable_scheduler()
On 10/28/2013 04:05 PM, Jan Beulich wrote: So commit eedd6039 ("scheduler: adjust internal locking interface") uncovered - by now using proper spin lock constructs - a bug after all: When bringing down a CPU, cpu_disable_scheduler() gets called with interrupts disabled, and hence the use of vcpu_schedule_lock_irq() was never really correct (i.e. the caller ended up with interrupts enabled despite having disabled them explicitly). Fixing this however surfaced another problem: The call path vcpu_migrate() -> evtchn_move_pirqs() wants to acquire the event lock, which however is a non-IRQ-safe once, and hence check_lock() doesn't like this lock to be acquired when interrupts are already off. As we're in stop-machine context here, getting things wrong wrt interrupt state management during lock acquire/release is out of question though, so the simple solution to this appears to be to just suppress spin lock debugging for the period of time while the stop machine callback gets run. Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx> Acked-by: George Dunlap <george.dunlap@xxxxxxxxxxxxx> _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxx http://lists.xen.org/xen-devel
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