On Wed, 5 Jun 2024 20:48:44 +0800
Jiwei Sun <sjiwei@xxxxxxx> wrote:
> From: Jiwei Sun <sunjw10@xxxxxxxxxx>
>
> During booting into the kernel, the following error message appears:
>
> (udev-worker)[2149]: nvme1n1: '/sbin/mdadm -I /dev/nvme1n1'(err)
> 'mdadm: Unable to get real path for
> '/sys/bus/pci/drivers/vmd/0000:c7:00.5/domain/device''
> (udev-worker)[2149]: nvme1n1: '/sbin/mdadm -I /dev/nvme1n1'(err)
> 'mdadm: /dev/nvme1n1 is not attached to Intel(R) RAID controller.'
> (udev-worker)[2149]: nvme1n1: '/sbin/mdadm -I /dev/nvme1n1'(err)
> 'mdadm: No OROM/EFI properties for /dev/nvme1n1' (udev-worker)[2149]:
> nvme1n1: '/sbin/mdadm -I /dev/nvme1n1'(err) 'mdadm: no RAID
> superblock on /dev/nvme1n1.' (udev-worker)[2149]: nvme1n1: Process
> '/sbin/mdadm -I /dev/nvme1n1' failed with exit code 1.
>
> This symptom prevents the OS from booting successfully.
>
> After a NVMe disk is probed/added by the nvme driver, the udevd
> executes some rule scripts by invoking mdadm command to detect if
> there is a mdraid associated with this NVMe disk. The mdadm
> determines if one NVMe devce is connected to a particular VMD domain
> by checking the domain symlink. Here is the root cause:
>
> Thread A Thread B Thread mdadm
> vmd_enable_domain
> pci_bus_add_devices
> __driver_probe_device
> ...
> work_on_cpu
> schedule_work_on
> : wakeup Thread B
> nvme_probe
> : wakeup scan_work
> to scan nvme disk
> and add nvme disk
> then wakeup udevd
> : udevd executes
> mdadm command
> flush_work main
> : wait for nvme_probe done ...
> __driver_probe_device find_driver_devices
> : probe next nvme device : 1) Detect the
> domain ... symlink; 2)
> Find the ... domain
> symlink from ... vmd
> sysfs; 3) The ... domain
> symlink is not ... created
> yet, failed sysfs_create_link
> : create domain symlink
>
> sysfs_create_link() is invoked at the end of vmd_enable_domain().
> However, this implementation introduces a timing issue, where mdadm
> might fail to retrieve the vmd symlink path because the symlink has
> not been created yet.
>
> Fix the issue by creating VMD domain symlinks before invoking
> pci_bus_add_devices().
>
> Signed-off-by: Jiwei Sun <sunjw10@xxxxxxxxxx>
> Suggested-by: Adrian Huang <ahuang12@xxxxxxxxxx>
> ---
> v3 changes:
> - Per Paul's comment, move sysfs_remove_link() after
> pci_stop_root_bus()
>
> v2 changes:
> - Add "()" after function names in subject and commit log
> - Move sysfs_create_link() after vmd_attach_resources()
>
> drivers/pci/controller/vmd.c | 8 ++++----
> 1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/pci/controller/vmd.c
> b/drivers/pci/controller/vmd.c index 87b7856f375a..4e7fe2e13cac 100644
> --- a/drivers/pci/controller/vmd.c
> +++ b/drivers/pci/controller/vmd.c
> @@ -925,6 +925,9 @@ static int vmd_enable_domain(struct vmd_dev *vmd,
> unsigned long features) dev_set_msi_domain(&vmd->bus->dev,
> dev_get_msi_domain(&vmd->dev->dev));
>
> + WARN(sysfs_create_link(&vmd->dev->dev.kobj,
> &vmd->bus->dev.kobj,
> + "domain"), "Can't create symlink to
> domain\n"); +
> vmd_acpi_begin();
>
> pci_scan_child_bus(vmd->bus);
> @@ -964,9 +967,6 @@ static int vmd_enable_domain(struct vmd_dev *vmd,
> unsigned long features) pci_bus_add_devices(vmd->bus);
>
> vmd_acpi_end();
> -
> - WARN(sysfs_create_link(&vmd->dev->dev.kobj,
> &vmd->bus->dev.kobj,
> - "domain"), "Can't create symlink to
> domain\n"); return 0;
> }
>
> @@ -1042,8 +1042,8 @@ static void vmd_remove(struct pci_dev *dev)
> {
> struct vmd_dev *vmd = pci_get_drvdata(dev);
>
> - sysfs_remove_link(&vmd->dev->dev.kobj, "domain");
> pci_stop_root_bus(vmd->bus);
> + sysfs_remove_link(&vmd->dev->dev.kobj, "domain");
> pci_remove_root_bus(vmd->bus);
> vmd_cleanup_srcu(vmd);
> vmd_detach_resources(vmd);
Reviewed-by: Nirmal Patel <nirmal.patel@xxxxxxxxxxxxxxx>
Thanks
-nirmal
