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@citrix.com>
[lizf: Backported to 3.4: adjust filename]
Signed-off-by: Zefan Li <lizefan@huawei.com>

diff --git a/drivers/tty/hvc/hvc_xen.c b/drivers/tty/hvc/hvc_xen.c
index 53e02b702a6664e0efca1cd55c3e7d366932535b..160b1f38c5dfb00b082dac0dbd24cb10bb657f7a 100644 (file)
--- a/drivers/tty/hvc/hvc_xen.c
+++ b/drivers/tty/hvc/hvc_xen.c
@@ -290,7 +290,7 @@ 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.c b/drivers/xen/events.c
index fdf842c83a7ab2689a8741ab4f2c0f19c6ee9332..d6e2deee7bf04c66c84248b411f32ff7a2523bb4 100644 (file)
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -906,7 +906,7 @@ static int find_virq(unsigned int virq, unsigned int cpu)
        return rc;
 }
 
-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;
@@ -920,8 +920,12 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
                if (irq == -1)
                        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;
@@ -1042,7 +1046,7 @@ 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 04399b28e821bf694a58d706e0b6c9f66e9c7d9f..f9cb6306511feefb7ed1b2fd99c7d13aa79d1dee 100644 (file)
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -12,7 +12,7 @@ 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,