From: Alex Williamson <alex.williamson@redhat.com> mainline inclusion from mainline-v6.10-rc1 commit cbb325e77fbe62a06184175aa98c9eb98736c3e8 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/IAD6H2 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i... --------------------------------------------------------- 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@intel.com> Reviewed-by: Cédric Le Goater <clg@redhat.com> Reviewed-by: Yi Liu <yi.l.liu@intel.com> Link: https://lore.kernel.org/r/20240516174831.2257970-1-alex.williamson@redhat.co... Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Signed-off-by: ZhangPeng <zhangpeng362@huawei.com> --- 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 a8f259bc2f4d..0524c90cedea 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; -- 2.25.1