From: Thomas Monjalon
> A device like failsafe can manage sub-devices.
> When removing such device, it removes its sub-devices and try to take the
> same vdev_device_list_lock.
> It was causing a deadlock because the lock was not recursive.
>
> Fixes: 35f462839b69 ("bus/vdev: add lock on device list")
>
> Suggested-by: Anatoly Burakov <anatoly.bura...@intel.com>
> Signed-off-by: Thomas Monjalon <tho...@monjalon.net>
Tested-by: Matan Azrad <ma...@mellanox.com>
> ---
> v3: try recursive lock
> WARNING: not yet tested!
> ---
> drivers/bus/vdev/vdev.c | 26 ++++++++++++++------------
> 1 file changed, 14 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/bus/vdev/vdev.c b/drivers/bus/vdev/vdev.c index
> 099b9ff85..6139dd551 100644
> --- a/drivers/bus/vdev/vdev.c
> +++ b/drivers/bus/vdev/vdev.c
> @@ -36,7 +36,9 @@ TAILQ_HEAD(vdev_device_list, rte_vdev_device);
>
> static struct vdev_device_list vdev_device_list =
> TAILQ_HEAD_INITIALIZER(vdev_device_list);
> -static rte_spinlock_t vdev_device_list_lock = RTE_SPINLOCK_INITIALIZER;
> +/* The lock needs to be recursive because a vdev can manage another
> +vdev. */ static rte_spinlock_recursive_t vdev_device_list_lock =
> + RTE_SPINLOCK_RECURSIVE_INITIALIZER;
>
> struct vdev_driver_list vdev_driver_list =
> TAILQ_HEAD_INITIALIZER(vdev_driver_list);
> @@ -249,7 +251,7 @@ rte_vdev_init(const char *name, const char *args)
> struct rte_devargs *devargs;
> int ret;
>
> - rte_spinlock_lock(&vdev_device_list_lock);
> + rte_spinlock_recursive_lock(&vdev_device_list_lock);
> ret = insert_vdev(name, args, &dev);
> if (ret == 0) {
> ret = vdev_probe_all_drivers(dev);
> @@ -263,7 +265,7 @@ rte_vdev_init(const char *name, const char *args)
> free(dev);
> }
> }
> - rte_spinlock_unlock(&vdev_device_list_lock);
> + rte_spinlock_recursive_unlock(&vdev_device_list_lock);
> return ret;
> }
>
> @@ -293,7 +295,7 @@ rte_vdev_uninit(const char *name)
> if (name == NULL)
> return -EINVAL;
>
> - rte_spinlock_lock(&vdev_device_list_lock);
> + rte_spinlock_recursive_lock(&vdev_device_list_lock);
>
> dev = find_vdev(name);
> if (!dev) {
> @@ -311,7 +313,7 @@ rte_vdev_uninit(const char *name)
> free(dev);
>
> unlock:
> - rte_spinlock_unlock(&vdev_device_list_lock);
> + rte_spinlock_recursive_unlock(&vdev_device_list_lock);
> return ret;
> }
>
> @@ -355,7 +357,7 @@ vdev_action(const struct rte_mp_msg *mp_msg, const
> void *peer)
> ou->num = 1;
> num = 0;
>
> - rte_spinlock_lock(&vdev_device_list_lock);
> + rte_spinlock_recursive_lock(&vdev_device_list_lock);
> TAILQ_FOREACH(dev, &vdev_device_list, next) {
> devname = rte_vdev_device_name(dev);
> if (strlen(devname) == 0) {
> @@ -369,7 +371,7 @@ vdev_action(const struct rte_mp_msg *mp_msg, const
> void *peer)
> devname, strerror(rte_errno));
> num++;
> }
> - rte_spinlock_unlock(&vdev_device_list_lock);
> + rte_spinlock_recursive_unlock(&vdev_device_list_lock);
>
> ou->type = VDEV_SCAN_REP;
> ou->num = num;
> @@ -445,10 +447,10 @@ vdev_scan(void)
> if (!dev)
> return -1;
>
> - rte_spinlock_lock(&vdev_device_list_lock);
> + rte_spinlock_recursive_lock(&vdev_device_list_lock);
>
> if (find_vdev(devargs->name)) {
> - rte_spinlock_unlock(&vdev_device_list_lock);
> +
> rte_spinlock_recursive_unlock(&vdev_device_list_lock);
> free(dev);
> continue;
> }
> @@ -459,7 +461,7 @@ vdev_scan(void)
>
> TAILQ_INSERT_TAIL(&vdev_device_list, dev, next);
>
> - rte_spinlock_unlock(&vdev_device_list_lock);
> + rte_spinlock_recursive_unlock(&vdev_device_list_lock);
> }
>
> return 0;
> @@ -498,7 +500,7 @@ vdev_find_device(const struct rte_device *start,
> rte_dev_cmp_t cmp,
> const struct rte_vdev_device *vstart;
> struct rte_vdev_device *dev;
>
> - rte_spinlock_lock(&vdev_device_list_lock);
> + rte_spinlock_recursive_lock(&vdev_device_list_lock);
> if (start != NULL) {
> vstart = RTE_DEV_TO_VDEV_CONST(start);
> dev = TAILQ_NEXT(vstart, next);
> @@ -510,7 +512,7 @@ vdev_find_device(const struct rte_device *start,
> rte_dev_cmp_t cmp,
> break;
> dev = TAILQ_NEXT(dev, next);
> }
> - rte_spinlock_unlock(&vdev_device_list_lock);
> + rte_spinlock_recursive_unlock(&vdev_device_list_lock);
>
> return dev ? &dev->device : NULL;
> }
> --
> 2.16.2
