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    xen: Do not suspend IPI IRQs. · 4877c737
    Ian Campbell 提交于
    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: NIan Campbell <ian.campbell@citrix.com>
    Cc: Jeremy Fitzhardinge <jeremy@goop.org>
    Cc: xen-devel@lists.xensource.com
    LKML-Reference: <1280398595-29708-4-git-send-email-ian.campbell@citrix.com>
    Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
    4877c737
events.c 21.2 KB