Any more comments? Or this one is not proper? On Thu, Aug 22, 2013 at 09:33:27PM -0600, Alex Williamson wrote: >[+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); > >
-- Richard Yang Help you, Help me _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
