On 21-May-18 5:11 PM, Thomas Monjalon wrote:
The lock vdev_device_list_lock was taken before calling "remove" function for the device. So it prevents to remove sub-devices (as in failsafe) inside its own "remove" function, because of a deadlock.The lock is now only protecting the device list inside the bus driver. Fixes: 35f462839b69 ("bus/vdev: add lock on device list") Signed-off-by: Thomas Monjalon <tho...@monjalon.net> --- drivers/bus/vdev/vdev.c | 10 ++++------ 1 file changed, 4 insertions(+), 6 deletions(-) diff --git a/drivers/bus/vdev/vdev.c b/drivers/bus/vdev/vdev.c index 099b9ff85..2fbc86806 100644 --- a/drivers/bus/vdev/vdev.c +++ b/drivers/bus/vdev/vdev.c @@ -293,25 +293,23 @@ rte_vdev_uninit(const char *name) if (name == NULL) return -EINVAL;- rte_spinlock_lock(&vdev_device_list_lock);- dev = find_vdev(name); if (!dev) { ret = -ENOENT; - goto unlock; + return ret; }
Without that lock, all of this would be racy - find_dev would iterate a tailq that might change under its feet, and tailq_remove may be called with a pointer that has already been removed.
How about changing the lock to a recursive lock? Failsafe would be removing devices from within the same thread, correct?
ret = vdev_remove_driver(dev);if (ret) - goto unlock; + return ret;+ rte_spinlock_lock(&vdev_device_list_lock);TAILQ_REMOVE(&vdev_device_list, dev, next); devargs = dev->device.devargs; rte_devargs_remove(devargs->bus->name, devargs->name); free(dev); - -unlock: rte_spinlock_unlock(&vdev_device_list_lock); + return ret; }
-- Thanks, Anatoly
