From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, David Vrabel , Konrad Rzeszutek Wilk Subject: [ 41/74] xen/events: initialize local per-cpu mask for all possible events Date: Mon, 26 Aug 2013 18:08:39 -0700 Message-Id: <20130827010433.061363187@linuxfoundation.org> In-Reply-To: <20130827010424.535365435@linuxfoundation.org> References: <20130827010424.535365435@linuxfoundation.org> Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.10-stable review patch. If anyone has any objections, please let me know. ------------------ From: David Vrabel 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: Greg Kroah-Hartman --- drivers/xen/events.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -346,7 +346,7 @@ static void init_evtchn_cpu_bindings(voi 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)