| Message ID | 1389584182-6349-1-git-send-email-shangw@linux.vnet.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Delegated to: | Benjamin Herrenschmidt |
| Headers | show |
On 01/13/2014 02:36 PM, Gavin Shan wrote: > Some devices, for example PCI root port, don't have IOMMU table and > group. We needn't detach them from their IOMMU group. Otherwise, it > potentially incurs kernel crash because of referring NULL IOMMU group > as following backtrace indicates: > > .iommu_group_remove_device+0x74/0x1b0 > .iommu_bus_notifier+0x94/0xb4 > .notifier_call_chain+0x78/0xe8 > .__blocking_notifier_call_chain+0x7c/0xbc > .blocking_notifier_call_chain+0x38/0x48 > .device_del+0x50/0x234 > .pci_remove_bus_device+0x88/0x138 > .pci_stop_and_remove_bus_device+0x2c/0x40 > .pcibios_remove_pci_devices+0xcc/0xfc > .pcibios_remove_pci_devices+0x3c/0xfc > > Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com> Thanks! I never tested the unplug case... Reviewed-by: Alexey Kardashevskiy <aik@ozlabs.ru> > --- > arch/powerpc/kernel/iommu.c | 11 +++++++++++ > 1 file changed, 11 insertions(+) > > diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c > index 572bb5b..8a49424 100644 > --- a/arch/powerpc/kernel/iommu.c > +++ b/arch/powerpc/kernel/iommu.c > @@ -1137,6 +1137,17 @@ static int iommu_add_device(struct device *dev) > > static void iommu_del_device(struct device *dev) > { > + /* > + * Some devices might not have IOMMU table and group > + * and we needn't detach them from the associated > + * IOMMU groups > + */ > + if (!dev->iommu_group) { > + pr_debug("iommu_tce: skipping device %s with no tbl\n", > + dev_name(dev)); > + return; > + } > + > iommu_group_remove_device(dev); > } > >
diff --git a/arch/powerpc/kernel/iommu.c b/arch/powerpc/kernel/iommu.c index 572bb5b..8a49424 100644 --- a/arch/powerpc/kernel/iommu.c +++ b/arch/powerpc/kernel/iommu.c @@ -1137,6 +1137,17 @@ static int iommu_add_device(struct device *dev) static void iommu_del_device(struct device *dev) { + /* + * Some devices might not have IOMMU table and group + * and we needn't detach them from the associated + * IOMMU groups + */ + if (!dev->iommu_group) { + pr_debug("iommu_tce: skipping device %s with no tbl\n", + dev_name(dev)); + return; + } + iommu_group_remove_device(dev); }
Some devices, for example PCI root port, don't have IOMMU table and group. We needn't detach them from their IOMMU group. Otherwise, it potentially incurs kernel crash because of referring NULL IOMMU group as following backtrace indicates: .iommu_group_remove_device+0x74/0x1b0 .iommu_bus_notifier+0x94/0xb4 .notifier_call_chain+0x78/0xe8 .__blocking_notifier_call_chain+0x7c/0xbc .blocking_notifier_call_chain+0x38/0x48 .device_del+0x50/0x234 .pci_remove_bus_device+0x88/0x138 .pci_stop_and_remove_bus_device+0x2c/0x40 .pcibios_remove_pci_devices+0xcc/0xfc .pcibios_remove_pci_devices+0x3c/0xfc Signed-off-by: Gavin Shan <shangw@linux.vnet.ibm.com> --- arch/powerpc/kernel/iommu.c | 11 +++++++++++ 1 file changed, 11 insertions(+)