Yi notes relative to commit f6944d4a0b87 ("vfio/pci: Collect hot-reset
devices to local buffer") that we previously tested the resulting
device count with a WARN_ON, which was removed when we switched to
the in-loop user copy in commit b56b7aabcf3c ("vfio/pci: Copy hot-reset
device info to userspace in the devices loop"). Finding no devices in
the bus/slot would be an unexpected condition, so let's restore the
warning and trigger a -ERANGE error here as success with no devices
would be an unexpected result to userspace as well.
Suggested-by: Yi Liu <yi.l.liu@xxxxxxxxx>
Signed-off-by: Alex Williamson <alex.williamson@xxxxxxxxxx>
---
drivers/vfio/pci/vfio_pci_core.c | 3 +++
1 file changed, 3 insertions(+)
diff --git a/drivers/vfio/pci/vfio_pci_core.c b/drivers/vfio/pci/vfio_pci_core.c
index d8c95cc16be8..80cae87fff36 100644
--- a/drivers/vfio/pci/vfio_pci_core.c
+++ b/drivers/vfio/pci/vfio_pci_core.c
@@ -1281,6 +1281,9 @@ static int vfio_pci_ioctl_get_pci_hot_reset_info(
if (ret)
return ret;
+ if (WARN_ON(!count)) /* Should always be at least one */
+ return -ERANGE;
+
if (count > (hdr.argsz - sizeof(hdr)) / sizeof(*devices)) {
hdr.count = count;
ret = -ENOSPC;
--
2.44.0
