Re: [Xen-devel] [PATCH] xen: resume console a bit later

[David Vrabel <david.vrabel@xxxxxxxxxx>]

On 02/07/14 17:58, Boris Ostrovsky wrote:
> On 07/02/2014 12:35 PM, David Vrabel wrote:
>> Calling xen_console_resume() in xen_suspend() causes a (harmless)
>> warning because it calls a function that might sleep.

It occurs to me that this warning isn't harmless.  Whilst the device
power management will ensure no driver is playing with irqs, a userspace
process might be using the evtchn device.

I've updated the commit message to:

    xen/manage: fix potential deadlock when resuming the console

    Calling xen_console_resume() in xen_suspend() causes a warning
    because it locks irq_mapping_update_lock (a mutex) and this may
    sleep.  If a userspace process is using the evtchn device then
    this mutex may be locked at the point of the stop_machine() call and
    xen_console_resume() would then deadlock.

    Resuming the console after stop_machine() returns avoids this
    deadlock.

And tagged for stable and applied to stable/for-linus-3.6

David

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