[3.19.y-ckt stable] Patch "xen/events: don't bind non-percpu VIRQs with percpu chip" has been added to staging queue
Kamal Mostafa
kamal at canonical.com
Tue Jun 16 00:22:58 UTC 2015
This is a note to let you know that I have just added a patch titled
xen/events: don't bind non-percpu VIRQs with percpu chip
to the linux-3.19.y-queue branch of the 3.19.y-ckt extended stable tree
which can be found at:
http://kernel.ubuntu.com/git/ubuntu/linux.git/log/?h=linux-3.19.y-queue
This patch is scheduled to be released in version 3.19.8-ckt2.
If you, or anyone else, feels it should not be added to this tree, please
reply to this email.
For more information about the 3.19.y-ckt tree, see
https://wiki.ubuntu.com/Kernel/Dev/ExtendedStable
Thanks.
-Kamal
------
>From ca0c1ac82e76a258a648889696e5158ff430565c Mon Sep 17 00:00:00 2001
From: David Vrabel <david.vrabel at citrix.com>
Date: Tue, 19 May 2015 18:40:49 +0100
Subject: xen/events: don't bind non-percpu VIRQs with percpu chip
commit 77bb3dfdc0d554befad58fdefbc41be5bc3ed38a upstream.
A non-percpu VIRQ (e.g., VIRQ_CONSOLE) may be freed on a different
VCPU than it is bound to. This can result in a race between
handle_percpu_irq() and removing the action in __free_irq() because
handle_percpu_irq() does not take desc->lock. The interrupt handler
sees a NULL action and oopses.
Only use the percpu chip/handler for per-CPU VIRQs (like VIRQ_TIMER).
# cat /proc/interrupts | grep virq
40: 87246 0 xen-percpu-virq timer0
44: 0 0 xen-percpu-virq debug0
47: 0 20995 xen-percpu-virq timer1
51: 0 0 xen-percpu-virq debug1
69: 0 0 xen-dyn-virq xen-pcpu
74: 0 0 xen-dyn-virq mce
75: 29 0 xen-dyn-virq hvc_console
Signed-off-by: David Vrabel <david.vrabel at citrix.com>
Signed-off-by: Kamal Mostafa <kamal at canonical.com>
---
drivers/tty/hvc/hvc_xen.c | 2 +-
drivers/xen/events/events_base.c | 12 ++++++++----
include/xen/events.h | 2 +-
3 files changed, 10 insertions(+), 6 deletions(-)
diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index 5bab1c6..7a3d146 100644
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -289,7 +289,7 @@ static int xen_initial_domain_console_init(void)
return -ENOMEM;
}
- info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0);
+ info->irq = bind_virq_to_irq(VIRQ_CONSOLE, 0, false);
info->vtermno = HVC_COOKIE;
spin_lock(&xencons_lock);
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 2b8553b..3838795 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -957,7 +957,7 @@ unsigned xen_evtchn_nr_channels(void)
}
EXPORT_SYMBOL_GPL(xen_evtchn_nr_channels);
-int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
+int bind_virq_to_irq(unsigned int virq, unsigned int cpu, bool percpu)
{
struct evtchn_bind_virq bind_virq;
int evtchn, irq, ret;
@@ -971,8 +971,12 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
if (irq < 0)
goto out;
- irq_set_chip_and_handler_name(irq, &xen_percpu_chip,
- handle_percpu_irq, "virq");
+ if (percpu)
+ irq_set_chip_and_handler_name(irq, &xen_percpu_chip,
+ handle_percpu_irq, "virq");
+ else
+ irq_set_chip_and_handler_name(irq, &xen_dynamic_chip,
+ handle_edge_irq, "virq");
bind_virq.virq = virq;
bind_virq.vcpu = cpu;
@@ -1062,7 +1066,7 @@ int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
{
int irq, retval;
- irq = bind_virq_to_irq(virq, cpu);
+ irq = bind_virq_to_irq(virq, cpu, irqflags & IRQF_PERCPU);
if (irq < 0)
return irq;
retval = request_irq(irq, handler, irqflags, devname, dev_id);
diff --git a/include/xen/events.h b/include/xen/events.h
index 5321cd9..7d95fdf 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -17,7 +17,7 @@ int bind_evtchn_to_irqhandler(unsigned int evtchn,
irq_handler_t handler,
unsigned long irqflags, const char *devname,
void *dev_id);
-int bind_virq_to_irq(unsigned int virq, unsigned int cpu);
+int bind_virq_to_irq(unsigned int virq, unsigned int cpu, bool percpu);
int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
irq_handler_t handler,
unsigned long irqflags, const char *devname,
--
1.9.1
More information about the kernel-team
mailing list