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| author | David Vrabel <david.vrabel@citrix.com> | 2015-05-19 18:40:49 +0100 |
|---|---|---|
| committer | Jiri Slaby <jslaby@suse.cz> | 2015-06-03 11:33:07 +0200 |
| commit | db02077307011751a0225845664bb212d76e87bc (patch) | |
| tree | 8d99709a9ce52cc3be145e2e9f815b85a76942c5 | |
| parent | 74b65e99d99c940a7fa731a317d13bc0b3b34911 (diff) | |
| download | lwn-db02077307011751a0225845664bb212d76e87bc.tar.gz lwn-db02077307011751a0225845664bb212d76e87bc.zip | |
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>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
| -rw-r--r-- | drivers/tty/hvc/hvc_xen.c | 2 | ||||
| -rw-r--r-- | drivers/xen/events.c | 12 | ||||
| -rw-r--r-- | 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 b4805adc50af..1dcee9a55914 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.c b/drivers/xen/events.c index 4035e833ea26..767fe735abd7 100644 --- a/drivers/xen/events.c +++ b/drivers/xen/events.c @@ -959,7 +959,7 @@ 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; @@ -973,8 +973,12 @@ 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; @@ -1101,7 +1105,7 @@ 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 c9ea10ee2273..7e1a8adc41fb 100644 --- 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, |