lkml.org 
[lkml]   [2020]   [Dec]   [28]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 5.10 207/717] RDMA/cma: Fix deadlock on &lock in rdma_cma_listen_on_all() error unwind
    Date
    From: Jason Gunthorpe <jgg@nvidia.com>

    [ Upstream commit dd37d2f59eb839d51b988f6668ce5f0d533b23fd ]

    rdma_detroy_id() cannot be called under &lock - we must instead keep the
    error'd ID around until &lock can be released, then destroy it.

    This is complicated by the usual way listen IDs are destroyed through
    cma_process_remove() which can run at any time and will asynchronously
    destroy the same ID.

    Remove the ID from visiblity of cma_process_remove() before going down the
    destroy path outside the locking.

    Fixes: c80a0c52d85c ("RDMA/cma: Add missing error handling of listen_id")
    Link: https://lore.kernel.org/r/20201118133756.GK244516@ziepe.ca
    Reported-by: syzbot+1bc48bf7f78253f664a9@syzkaller.appspotmail.com
    Reviewed-by: Leon Romanovsky <leonro@nvidia.com>
    Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    drivers/infiniband/core/cma.c | 25 ++++++++++++++++++-------
    1 file changed, 18 insertions(+), 7 deletions(-)

    diff --git a/drivers/infiniband/core/cma.c b/drivers/infiniband/core/cma.c
    index 4585f654f8836..c06c87a4dc5e7 100644
    --- a/drivers/infiniband/core/cma.c
    +++ b/drivers/infiniband/core/cma.c
    @@ -2496,7 +2496,8 @@ static int cma_listen_handler(struct rdma_cm_id *id,
    }

    static int cma_listen_on_dev(struct rdma_id_private *id_priv,
    - struct cma_device *cma_dev)
    + struct cma_device *cma_dev,
    + struct rdma_id_private **to_destroy)
    {
    struct rdma_id_private *dev_id_priv;
    struct net *net = id_priv->id.route.addr.dev_addr.net;
    @@ -2504,6 +2505,7 @@ static int cma_listen_on_dev(struct rdma_id_private *id_priv,

    lockdep_assert_held(&lock);

    + *to_destroy = NULL;
    if (cma_family(id_priv) == AF_IB && !rdma_cap_ib_cm(cma_dev->device, 1))
    return 0;

    @@ -2518,7 +2520,6 @@ static int cma_listen_on_dev(struct rdma_id_private *id_priv,
    rdma_addr_size(cma_src_addr(id_priv)));

    _cma_attach_to_dev(dev_id_priv, cma_dev);
    - list_add_tail(&dev_id_priv->listen_list, &id_priv->listen_list);
    cma_id_get(id_priv);
    dev_id_priv->internal_id = 1;
    dev_id_priv->afonly = id_priv->afonly;
    @@ -2528,25 +2529,31 @@ static int cma_listen_on_dev(struct rdma_id_private *id_priv,
    ret = rdma_listen(&dev_id_priv->id, id_priv->backlog);
    if (ret)
    goto err_listen;
    + list_add_tail(&dev_id_priv->listen_list, &id_priv->listen_list);
    return 0;
    err_listen:
    - list_del(&id_priv->listen_list);
    + /* Caller must destroy this after releasing lock */
    + *to_destroy = dev_id_priv;
    dev_warn(&cma_dev->device->dev, "RDMA CMA: %s, error %d\n", __func__, ret);
    - rdma_destroy_id(&dev_id_priv->id);
    return ret;
    }

    static int cma_listen_on_all(struct rdma_id_private *id_priv)
    {
    + struct rdma_id_private *to_destroy;
    struct cma_device *cma_dev;
    int ret;

    mutex_lock(&lock);
    list_add_tail(&id_priv->list, &listen_any_list);
    list_for_each_entry(cma_dev, &dev_list, list) {
    - ret = cma_listen_on_dev(id_priv, cma_dev);
    - if (ret)
    + ret = cma_listen_on_dev(id_priv, cma_dev, &to_destroy);
    + if (ret) {
    + /* Prevent racing with cma_process_remove() */
    + if (to_destroy)
    + list_del_init(&to_destroy->list);
    goto err_listen;
    + }
    }
    mutex_unlock(&lock);
    return 0;
    @@ -2554,6 +2561,8 @@ static int cma_listen_on_all(struct rdma_id_private *id_priv)
    err_listen:
    list_del(&id_priv->list);
    mutex_unlock(&lock);
    + if (to_destroy)
    + rdma_destroy_id(&to_destroy->id);
    return ret;
    }

    @@ -4855,6 +4864,7 @@ static void cma_process_remove(struct cma_device *cma_dev)

    static int cma_add_one(struct ib_device *device)
    {
    + struct rdma_id_private *to_destroy;
    struct cma_device *cma_dev;
    struct rdma_id_private *id_priv;
    unsigned int i;
    @@ -4902,7 +4912,7 @@ static int cma_add_one(struct ib_device *device)
    mutex_lock(&lock);
    list_add_tail(&cma_dev->list, &dev_list);
    list_for_each_entry(id_priv, &listen_any_list, list) {
    - ret = cma_listen_on_dev(id_priv, cma_dev);
    + ret = cma_listen_on_dev(id_priv, cma_dev, &to_destroy);
    if (ret)
    goto free_listen;
    }
    @@ -4915,6 +4925,7 @@ free_listen:
    list_del(&cma_dev->list);
    mutex_unlock(&lock);

    + /* cma_process_remove() will delete to_destroy */
    cma_process_remove(cma_dev);
    kfree(cma_dev->default_roce_tos);
    free_gid_type:
    --
    2.27.0


    \
     
     \ /
      Last update: 2020-12-28 15:10    [W:6.420 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site