3.2.92-rc1 review patch. If anyone has any objections, please let me know. ------------------ From: "Michael J. Ruhl" <michael.j.ruhl@xxxxxxxxx> commit 20c7840a77ddcb2ed2fbd66e8197db2868495751 upstream. 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") 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> [bwh: Backported to 3.2: adjust context] Signed-off-by: Ben Hutchings <ben@xxxxxxxxxxxxxxx> --- drivers/infiniband/core/uverbs_cmd.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) --- a/drivers/infiniband/core/uverbs_cmd.c +++ b/drivers/infiniband/core/uverbs_cmd.c @@ -2440,6 +2440,7 @@ ssize_t ib_uverbs_detach_mcast(struct ib 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; @@ -2448,10 +2449,6 @@ ssize_t ib_uverbs_detach_mcast(struct ib if (!qp) return -EINVAL; - ret = ib_detach_mcast(qp, (union ib_gid *) cmd.gid, cmd.mlid); - if (ret) - goto out_put; - obj = container_of(qp->uobject, struct ib_uqp_object, uevent.uobject); list_for_each_entry(mcast, &obj->mcast_list, list) @@ -2459,9 +2456,17 @@ ssize_t ib_uverbs_detach_mcast(struct ib !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: put_qp_write(qp);