On Thu, May 3, 2012 at 5:52 PM, Bjorn Helgaas <bhelgaas@xxxxxxxxxx> wrote: > On Fri, Apr 27, 2012 at 1:00 PM, Khalid Aziz <khalid.aziz@xxxxxx> wrote: >> Disable Bus Master bit on the device in >> pci_device_shutdown() to ensure PCI devices do not continue >> to DMA data after shutdown. This can cause memory >> corruption in case of a kexec where the current kernel >> shuts down and transfers control to a new kernel while a >> PCI device continues to DMA to memory that does not belong >> to it any more in the new kernel. >> >> I have tested this code on two laptops, two workstations and >> a 16-socket server. kexec worked correctly on all of them. >> >> >> Signed-off-by: Khalid Aziz <khalid.aziz@xxxxxx> >> --- >> drivers/pci/pci-driver.c | 6 ++++++ >> 1 files changed, 6 insertions(+), 0 deletions(-) >> >> diff --git a/drivers/pci/pci-driver.c b/drivers/pci/pci-driver.c >> index 6b54b23..9db5940 100644 >> --- a/drivers/pci/pci-driver.c >> +++ b/drivers/pci/pci-driver.c >> @@ -420,6 +420,12 @@ static void pci_device_shutdown(struct device *dev) >> pci_msi_shutdown(pci_dev); >> pci_msix_shutdown(pci_dev); >> >> + /* >> + * Turn off Bus Master bit on the device to tell it to not >> + * continue to do DMA >> + */ >> + pci_disable_device(pci_dev); >> + >> /* >> * Devices may be enabled to wake up by runtime PM, but they need not >> * be supposed to wake up the system from its "power off" state (e.g. > > Any comment on this, Eric? It seems reasonable to me. Applied to my "next" branch, thanks. Bjorn -- To unsubscribe from this list: send the line "unsubscribe linux-pci" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
