| Date | Wed, 11 Sep 2013 00:30:46 -0400 | From | Steven Rostedt <> | Subject | [219/251] xen/events: initialize local per-cpu mask for all possible events |
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3.6.11.9-rc1 stable review patch. If anyone has any objections, please let me know.
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From: David Vrabel <david.vrabel@citrix.com>
[ Upstream commit 84ca7a8e45dafb49cd5ca90a343ba033e2885c17 ]
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 <david.vrabel@citrix.com> Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> CC: stable@vger.kernel.org Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- drivers/xen/events.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/xen/events.c b/drivers/xen/events.c index 99c5345..3987f6f 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -324,7 +324,7 @@ 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) -- 1.7.10.4
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