[+cc Lukas, -stable]
On Thu, Aug 09, 2018 at 10:33:56AM -0600, Keith Busch wrote:
> PCI enumeration/de-enumeration needs to run single threaded to prevent
> race conditions with other threads changing the topology. Altering the
> number of virtual functions was not taking the rescan/remove lock hile
> adding or removing those virtual functions, so this patch adds that.
>
> Reported-by: Krzysztof Wierzbicki <krzysztof.wierzbicki@xxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> Signed-off-by: Keith Busch <keith.busch@xxxxxxxxx>
> ---
> drivers/pci/pci-sysfs.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/pci/pci-sysfs.c b/drivers/pci/pci-sysfs.c
> index 9ecfe13157c0..611abe220b6f 100644
> --- a/drivers/pci/pci-sysfs.c
> +++ b/drivers/pci/pci-sysfs.c
> @@ -591,6 +591,7 @@ static ssize_t sriov_numvfs_store(struct device *dev,
> if (num_vfs > pci_sriov_get_totalvfs(pdev))
> return -ERANGE;
>
> + pci_lock_rescan_remove();
I assume the usual path is something like this, where we end up in
pci_enable_sriov():
sriov_numvfs_store
+ pci_lock_rescan_remove
pdev->driver->sriov_configure
...
pci_enable_sriov
sriov_enable
pci_iov_add_virtfn
pci_alloc_dev
pci_device_add
But what about the other paths leading to pci_iov_add_virtfn()? Don't
we need similar locking for all of them?
> device_lock(&pdev->dev);
>
> if (num_vfs == pdev->sriov->num_VFs)
> @@ -627,6 +628,7 @@ static ssize_t sriov_numvfs_store(struct device *dev,
>
> exit:
> device_unlock(&pdev->dev);
> + pci_unlock_rescan_remove();
>
> if (ret < 0)
> return ret;
> --
> 2.14.4
>
