This is a note to let you know that I've just added the patch titled
xen/events: initialize local per-cpu mask for all possible events
to the 3.0-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
xen-events-initialize-local-per-cpu-mask-for-all-possible-events.patch
and it can be found in the queue-3.0 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 84ca7a8e45dafb49cd5ca90a343ba033e2885c17 Mon Sep 17 00:00:00 2001
From: David Vrabel <david.vrabel@xxxxxxxxxx>
Date: Thu, 15 Aug 2013 13:21:06 +0100
Subject: xen/events: initialize local per-cpu mask for all possible events
From: David Vrabel <david.vrabel@xxxxxxxxxx>
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 <david.vrabel@xxxxxxxxxx>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/xen/events.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -317,7 +317,7 @@ 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)
Patches currently in stable-queue which might be from david.vrabel@xxxxxxxxxx are
queue-3.0/xen-events-initialize-local-per-cpu-mask-for-all-possible-events.patch
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