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authorVitaly Kuznetsov <vkuznets@redhat.com>2015-01-05 16:27:51 +0100
committerDavid Vrabel <david.vrabel@citrix.com>2015-01-08 13:55:25 +0000
commit7be0772d19103b3eac3c2e9ac325df2563273fdc (patch)
tree649728c76fed0d5e0a9766971d9f3376f8eea785 /arch/x86
parenta97dae1a2e92e728d28515e88e8eda151f5796f5 (diff)
downloadop-kernel-dev-7be0772d19103b3eac3c2e9ac325df2563273fdc.zip
op-kernel-dev-7be0772d19103b3eac3c2e9ac325df2563273fdc.tar.gz
x86/xen: avoid freeing static 'name' when kasprintf() fails
In case kasprintf() fails in xen_setup_timer() we assign name to the static string "<timer kasprintf failed>". We, however, don't check that fact before issuing kfree() in xen_teardown_timer(), kernel is supposed to crash with 'kernel BUG at mm/slub.c:3341!' Solve the issue by making name a fixed length string inside struct xen_clock_event_device. 16 bytes should be enough. Suggested-by: Laszlo Ersek <lersek@redhat.com> Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com> Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Diffstat (limited to 'arch/x86')
-rw-r--r--arch/x86/xen/time.c16
1 files changed, 5 insertions, 11 deletions
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index 23019b4..6908734 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -391,7 +391,7 @@ static const struct clock_event_device *xen_clockevent =
struct xen_clock_event_device {
struct clock_event_device evt;
- char *name;
+ char name[16];
};
static DEFINE_PER_CPU(struct xen_clock_event_device, xen_clock_events) = { .evt.irq = -1 };
@@ -420,39 +420,33 @@ void xen_teardown_timer(int cpu)
if (evt->irq >= 0) {
unbind_from_irqhandler(evt->irq, NULL);
evt->irq = -1;
- kfree(per_cpu(xen_clock_events, cpu).name);
- per_cpu(xen_clock_events, cpu).name = NULL;
}
}
void xen_setup_timer(int cpu)
{
- char *name;
- struct clock_event_device *evt;
+ struct xen_clock_event_device *xevt = &per_cpu(xen_clock_events, cpu);
+ struct clock_event_device *evt = &xevt->evt;
int irq;
- evt = &per_cpu(xen_clock_events, cpu).evt;
WARN(evt->irq >= 0, "IRQ%d for CPU%d is already allocated\n", evt->irq, cpu);
if (evt->irq >= 0)
xen_teardown_timer(cpu);
printk(KERN_INFO "installing Xen timer for CPU %d\n", cpu);
- name = kasprintf(GFP_KERNEL, "timer%d", cpu);
- if (!name)
- name = "<timer kasprintf failed>";
+ snprintf(xevt->name, sizeof(xevt->name), "timer%d", cpu);
irq = bind_virq_to_irqhandler(VIRQ_TIMER, cpu, xen_timer_interrupt,
IRQF_PERCPU|IRQF_NOBALANCING|IRQF_TIMER|
IRQF_FORCE_RESUME|IRQF_EARLY_RESUME,
- name, NULL);
+ xevt->name, NULL);
(void)xen_set_irq_priority(irq, XEN_IRQ_PRIORITY_MAX);
memcpy(evt, xen_clockevent, sizeof(*evt));
evt->cpumask = cpumask_of(cpu);
evt->irq = irq;
- per_cpu(xen_clock_events, cpu).name = name;
}
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