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xen: Do not suspend IPI IRQs.
commit 4877c73 upstream. In general the semantics of IPIs are that they are are expected to continue functioning after dpm_suspend_noirq(). Specifically I have seen a deadlock between the callfunc IPI and the stop machine used by xen's do_suspend() routine. If one CPU has already called dpm_suspend_noirq() then there is a window where it can be sent a callfunc IPI before all the other CPUs have entered stop_cpu(). If this happens then the first CPU ends up spinning in stop_cpu() waiting for the other to rendezvous in state STOPMACHINE_PREPARE while the other is spinning in csd_lock_wait(). Signed-off-by: Ian Campbell <email@example.com> Cc: Jeremy Fitzhardinge <firstname.lastname@example.org> Cc: email@example.com LKML-Reference: <firstname.lastname@example.org> Signed-off-by: Thomas Gleixner <email@example.com> Signed-off-by: Greg Kroah-Hartman <firstname.lastname@example.org>
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