This is a note to let you know that I've just added the patch titled PCI: Fix pci_device_is_present() for VFs by checking PF to the 6.1-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: pci-fix-pci_device_is_present-for-vfs-by-checking-pf.patch and it can be found in the queue-6.1 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@xxxxxxxxxxxxxxx> know about it. >From 98b04dd0b4577894520493d96bc4623387767445 Mon Sep 17 00:00:00 2001 From: "Michael S. Tsirkin" <mst@xxxxxxxxxx> Date: Wed, 26 Oct 2022 02:11:21 -0400 Subject: PCI: Fix pci_device_is_present() for VFs by checking PF From: Michael S. Tsirkin <mst@xxxxxxxxxx> commit 98b04dd0b4577894520493d96bc4623387767445 upstream. pci_device_is_present() previously didn't work for VFs because it reads the Vendor and Device ID, which are 0xffff for VFs, which looks like they aren't present. Check the PF instead. Wei Gong reported that if virtio I/O is in progress when the driver is unbound or "0" is written to /sys/.../sriov_numvfs, the virtio I/O operation hangs, which may result in output like this: task:bash state:D stack: 0 pid: 1773 ppid: 1241 flags:0x00004002 Call Trace: schedule+0x4f/0xc0 blk_mq_freeze_queue_wait+0x69/0xa0 blk_mq_freeze_queue+0x1b/0x20 blk_cleanup_queue+0x3d/0xd0 virtblk_remove+0x3c/0xb0 [virtio_blk] virtio_dev_remove+0x4b/0x80 ... device_unregister+0x1b/0x60 unregister_virtio_device+0x18/0x30 virtio_pci_remove+0x41/0x80 pci_device_remove+0x3e/0xb0 This happened because pci_device_is_present(VF) returned "false" in virtio_pci_remove(), so it called virtio_break_device(). The broken vq meant that vring_interrupt() skipped the vq.callback() that would have completed the virtio I/O operation via virtblk_done(). [bhelgaas: commit log, simplify to always use pci_physfn(), add stable tag] Link: https://lore.kernel.org/r/20221026060912.173250-1-mst@xxxxxxxxxx Reported-by: Wei Gong <gongwei833x@xxxxxxxxx> Tested-by: Wei Gong <gongwei833x@xxxxxxxxx> Signed-off-by: Michael S. Tsirkin <mst@xxxxxxxxxx> Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx> Cc: stable@xxxxxxxxxxxxxxx Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx> --- drivers/pci/pci.c | 2 ++ 1 file changed, 2 insertions(+) --- a/drivers/pci/pci.c +++ b/drivers/pci/pci.c @@ -6447,6 +6447,8 @@ bool pci_device_is_present(struct pci_de { u32 v; + /* Check PF if pdev is a VF, since VF Vendor/Device IDs are 0xffff */ + pdev = pci_physfn(pdev); if (pci_dev_is_disconnected(pdev)) return false; return pci_bus_read_dev_vendor_id(pdev->bus, pdev->devfn, &v, 0); Patches currently in stable-queue which might be from mst@xxxxxxxxxx are queue-6.1/um-virt-pci-avoid-gcc-non-null-warning.patch queue-6.1/pci-fix-pci_device_is_present-for-vfs-by-checking-pf.patch