[+cc iommu] On Fri, 2013-08-23 at 09:55 +0800, Wei Yang wrote: > When removing a device from the system, iommu_group driver will try to > disconnect it from its group. While in some cases, one device may not > associated with any iommu_group. For example, not enough DMA address space. > > In the generic bus notification, it will check dev->iommu_group before calling > iommu_group_remove_device(). While in some cases, developers may call > iommu_group_remove_device() in a different code path and without check. For > those devices with dev->iommu_group set to NULL, kernel will crash. > > This patch gives a warning and return when trying to remove a device from an > iommu_group with dev->iommu_group set to NULL. This helps to indicate some bad > behavior and also guard the kernel. > > Signed-off-by: Wei Yang <weiy...@linux.vnet.ibm.com>
Acked-by: Alex Williamson <alex.william...@redhat.com> > --- > drivers/iommu/iommu.c | 3 +++ > 1 files changed, 3 insertions(+), 0 deletions(-) > > diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c > index fbe9ca7..43396f0 100644 > --- a/drivers/iommu/iommu.c > +++ b/drivers/iommu/iommu.c > @@ -379,6 +379,9 @@ void iommu_group_remove_device(struct device *dev) > struct iommu_group *group = dev->iommu_group; > struct iommu_device *tmp_device, *device = NULL; > > + if (WARN_ON(!group)) > + return; > + > /* Pre-notify listeners that a device is being removed. */ > blocking_notifier_call_chain(&group->notifier, > IOMMU_GROUP_NOTIFY_DEL_DEVICE, dev); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
