tree b89335776098f706f6a55adc46b29c2d33d12277
parent 4b17acfb9c0485e9af31746ecec8bcc0d6d767c4
author Ross Lagerwall <ross.lagerwall@citrix.com> 1408354896 +0100
committer chrmhoffmann <chrmhoffmann@gmail.com> 1586074842 +0200

xen/manage: Always freeze/thaw processes when suspend/resuming

commit 61a734d305e16944b42730ef582a7171dc733321 upstream.

Always freeze processes when suspending and thaw processes when resuming
to prevent a race noticeable with HVM guests.

This prevents a deadlock where the khubd kthread (which is designed to
be freezable) acquires a usb device lock and then tries to allocate
memory which requires the disk which hasn't been resumed yet.
Meanwhile, the xenwatch thread deadlocks waiting for the usb device
lock.

Freezing processes fixes this because the khubd thread is only thawed
after the xenwatch thread finishes resuming all the devices.

Signed-off-by: Ross Lagerwall <ross.lagerwall@citrix.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
[lizf: Backported to 3.4: adjust context]
Signed-off-by: Zefan Li <lizefan@huawei.com>