ping On 09/18/2018 05:15 PM, Alexandru Gagniuc wrote:
When a PCI device is gone, we don't want to send IO to it if we can avoid it. We expose functionality via the irq_chip structure. As users of that structure may not know about the underlying PCI device, it's our responsibility to guard against removed devices. .irq_write_msi_msg() is already guarded inside __pci_write_msi_msg(). .irq_mask/unmask() are not. Guard them for completeness. For example, surprise removal of a PCIe device triggers teardown. This touches the irq_chips ops some point to disable the interrupts. I/O generated here can crash the system on firmware-first machines. Not triggering the IO in the first place greatly reduces the possibility of the problem occurring. Signed-off-by: Alexandru Gagniuc <mr.nuke.me@xxxxxxxxx> --- drivers/pci/msi.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/drivers/pci/msi.c b/drivers/pci/msi.c index f2ef896464b3..f31058fd2260 100644 --- a/drivers/pci/msi.c +++ b/drivers/pci/msi.c @@ -227,6 +227,9 @@ static void msi_set_mask_bit(struct irq_data *data, u32 flag) { struct msi_desc *desc = irq_data_get_msi_desc(data);+ if (pci_dev_is_disconnected(msi_desc_to_pci_dev(desc)))+ return; + if (desc->msi_attrib.is_msix) { msix_mask_irq(desc, flag); readl(desc->mask_base); /* Flush write to device */
