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FAILED: patch "[PATCH] IB/core: If the MGID/MLID pair is not on the list return an" failed to apply to 4.9-stable tree

PATCH [email protected] 1 participant 1 message May 17, 2017

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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 <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 20c7840a77ddcb2ed2fbd66e8197db2868495751 Mon Sep 17 00:00:00 2001

From: "Michael J. Ruhl" <[email protected]>
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 [email protected]
Reviewed-by Ira Weiny <[email protected]>
Reviewed-by Leon Romanovsky <[email protected]>
Signed-off-by Michael J. Ruhl <[email protected]>
Signed-off-by Dennis Dalessandro <[email protected]>
Signed-off-by Doug Ledford <[email protected]>
drivers/infiniband/core/uverbs_cmd.c +9 -4
index 7a4a10ef8b49..cb3c426c0dad 100644
@@ -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);