From: David Vrabel Date: Thu, 15 Aug 2013 12:21:06 +0000 (+0100) Subject: xen/events: initialize local per-cpu mask for all possible events X-Git-Tag: v3.2.51~42 X-Git-Url: https://git.openpandora.org/cgi-bin/gitweb.cgi?p=pandora-kernel.git;a=commitdiff_plain;h=63493b3e3db6d027fe9b9a53616b8c1a9038ea44;hp=343077dc5d8ec1fe65caf734d5d4205ac35b3ab2 xen/events: initialize local per-cpu mask for all possible events commit 84ca7a8e45dafb49cd5ca90a343ba033e2885c17 upstream. The sizeof() argument in init_evtchn_cpu_bindings() is incorrect resulting in only the first 64 (or 32 in 32-bit guests) ports having their bindings being initialized to VCPU 0. In most cases this does not cause a problem as request_irq() will set the irq affinity which will set the correct local per-cpu mask. However, if the request_irq() is called on a VCPU other than 0, there is a window between the unmasking of the event and the affinity being set were an event may be lost because it is not locally unmasked on any VCPU. If request_irq() is called on VCPU 0 then local irqs are disabled during the window and the race does not occur. Fix this by initializing all NR_EVENT_CHANNEL bits in the local per-cpu masks. Signed-off-by: David Vrabel Signed-off-by: Konrad Rzeszutek Wilk Signed-off-by: Ben Hutchings --- diff --git a/drivers/xen/events.c b/drivers/xen/events.c index 11d7b6443107..58236dd5c3c9 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -316,7 +316,7 @@ static void init_evtchn_cpu_bindings(void) for_each_possible_cpu(i) memset(per_cpu(cpu_evtchn_mask, i), - (i == 0) ? ~0 : 0, sizeof(*per_cpu(cpu_evtchn_mask, i))); + (i == 0) ? ~0 : 0, NR_EVENT_CHANNELS/8); } static inline void clear_evtchn(int port)