The patch below does not apply to the 4.9-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <stable@xxxxxxxxxxxxxxx>. thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 20c7840a77ddcb2ed2fbd66e8197db2868495751 Mon Sep 17 00:00:00 2001 From: "Michael J. Ruhl" <michael.j.ruhl@xxxxxxxxx> Date: Sun, 9 Apr 2017 10:15:32 -0700 Subject: [PATCH] IB/core: If the MGID/MLID pair is not on the list return an error A list of MGID/MLID pairs is built when doing a multicast attach. When the multicast detach is called, the list is searched, and regardless of the search outcome, the driver detach is called. If an MGID/MLID pair is not on the list, driver detach should not be called, and an error should be returned. Calling the driver without removing an MGID/MLID pair from the list can leave the core and driver out of sync. Fixes: f4e401562c11 ("IB/uverbs: track multicast group membership for userspace QPs") Cc: stable@xxxxxxxxxxxxxxx Reviewed-by: Ira Weiny <ira.weiny@xxxxxxxxx> Reviewed-by: Leon Romanovsky <leonro@xxxxxxxxxxxx> Signed-off-by: Michael J. Ruhl <michael.j.ruhl@xxxxxxxxx> Signed-off-by: Dennis Dalessandro <dennis.dalessandro@xxxxxxxxx> Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx> diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c index 7a4a10ef8b49..cb3c426c0dad 100644 --- a/drivers/infiniband/core/uverbs_cmd.c +++ b/drivers/infiniband/core/uverbs_cmd.c @@ -2658,6 +2658,7 @@ ssize_t ib_uverbs_detach_mcast(struct ib_uverbs_file *file, struct ib_qp *qp; struct ib_uverbs_mcast_entry *mcast; int ret = -EINVAL; + bool found = false; if (copy_from_user(&cmd, buf, sizeof cmd)) return -EFAULT; @@ -2669,18 +2670,22 @@ ssize_t ib_uverbs_detach_mcast(struct ib_uverbs_file *file, obj = container_of(qp->uobject, struct ib_uqp_object, uevent.uobject); mutex_lock(&obj->mcast_lock); - ret = ib_detach_mcast(qp, (union ib_gid *) cmd.gid, cmd.mlid); - if (ret) - goto out_put; - list_for_each_entry(mcast, &obj->mcast_list, list) if (cmd.mlid == mcast->lid && !memcmp(cmd.gid, mcast->gid.raw, sizeof mcast->gid.raw)) { list_del(&mcast->list); kfree(mcast); + found = true; break; } + if (!found) { + ret = -EINVAL; + goto out_put; + } + + ret = ib_detach_mcast(qp, (union ib_gid *)cmd.gid, cmd.mlid); + out_put: mutex_unlock(&obj->mcast_lock); uobj_put_obj_read(qp);