| Message ID | 20090521062135.GR20823@sequoia.sous-sol.org (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
Chris Wright wrote: > Commit "32658734: Fix request_irq() for < 2.6.19" is racy between multiple > guests since ioctl is only serialized per guest. Add mutex and serialize > kvm_request_irq/kvm_free_irq to avoid race. > > Signed-off-by: Chris Wright <chrisw@redhat.com> > --- > external-module-compat-comm.h | 14 +++++++++++--- > 1 files changed, 11 insertions(+), 3 deletions(-) > > diff --git a/external-module-compat-comm.h b/external-module-compat-comm.h > index 8cb5440..eaad986 100644 > --- a/external-module-compat-comm.h > +++ b/external-module-compat-comm.h > @@ -645,6 +645,7 @@ static inline int pci_reset_function(struct pci_dev *dev) > > typedef irqreturn_t (*kvm_irq_handler_t)(int, void *); > static kvm_irq_handler_t kvm_irq_handlers[NR_IRQS]; > +static DEFINE_MUTEX(kvm_irq_handlers_mutex); > > Since this mutex is in a header file, it can be instantiated multiple times. It will only serialize callers within a translation unit. Please define it in a C file. Would be best to move the the code as well.
* Avi Kivity (avi@redhat.com) wrote: > Since this mutex is in a header file, it can be instantiated multiple > times. It will only serialize callers within a translation unit. > Please define it in a C file. > > Would be best to move the the code as well. Yeah it seems to get linked multiple times (when I tried that I found duplicates). I'll look again. thanks, -chris -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
diff --git a/external-module-compat-comm.h b/external-module-compat-comm.h index 8cb5440..eaad986 100644 --- a/external-module-compat-comm.h +++ b/external-module-compat-comm.h @@ -645,6 +645,7 @@ static inline int pci_reset_function(struct pci_dev *dev) typedef irqreturn_t (*kvm_irq_handler_t)(int, void *); static kvm_irq_handler_t kvm_irq_handlers[NR_IRQS]; +static DEFINE_MUTEX(kvm_irq_handlers_mutex); static irqreturn_t kvm_irq_thunk(int irq, void *dev_id, struct pt_regs *regs) { @@ -655,21 +656,28 @@ static irqreturn_t kvm_irq_thunk(int irq, void *dev_id, struct pt_regs *regs) static inline int kvm_request_irq(unsigned int a, kvm_irq_handler_t handler, unsigned long c, const char *d, void *e) { - int rc; - kvm_irq_handler_t old = kvm_irq_handlers[a]; + int rc = -EBUSY; + kvm_irq_handler_t old; + + mutex_lock(&kvm_irq_handlers_mutex); + old = kvm_irq_handlers[a]; if (old) - return -EBUSY; + goto out; kvm_irq_handlers[a] = handler; rc = request_irq(a, kvm_irq_thunk, c, d, e); if (rc) kvm_irq_handlers[a] = NULL; +out: + mutex_unlock(&kvm_irq_handlers_mutex); return rc; } static inline void kvm_free_irq(unsigned int irq, void *dev_id) { + mutex_lock(&kvm_irq_handlers_mutex); free_irq(irq, dev_id); kvm_irq_handlers[irq] = NULL; + mutex_unlock(&kvm_irq_handlers_mutex); } #else
Commit "32658734: Fix request_irq() for < 2.6.19" is racy between multiple guests since ioctl is only serialized per guest. Add mutex and serialize kvm_request_irq/kvm_free_irq to avoid race. Signed-off-by: Chris Wright <chrisw@redhat.com> --- external-module-compat-comm.h | 14 +++++++++++--- 1 files changed, 11 insertions(+), 3 deletions(-) -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html