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List:       linux-rdma
Subject:    [PATCH for-next 4/4] IB/core: Fix deadlock on uverbs modify_qp error flow
From:       Or Gerlitz <ogerlitz () mellanox ! com>
Date:       2015-01-29 9:00:33
Message-ID: 1422522033-3024-5-git-send-email-ogerlitz () mellanox ! com
[Download RAW message or body]

From: Moshe Lazer <moshel@mellanox.com>

The deadlock occurs on __uverbs_modify_qp, we take a lock (idr_read_qp)
and in case of failure in ib_resolve_eth_l2_attrs we don't release
it (put_qp_read). Fix that.

Issue: 355606
Fixes: ed4c54e5b4ba ("IB/core: Resolve Ethernet L2 addresses when modifying QP")
Signed-off-by: Moshe Lazer <moshel@mellanox.com>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
---
 drivers/infiniband/core/uverbs_cmd.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/drivers/infiniband/core/uverbs_cmd.c b/drivers/infiniband/core/uverbs_cmd.c
index ecb6430..a602ce9 100644
--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -2097,20 +2097,21 @@ ssize_t ib_uverbs_modify_qp(struct ib_uverbs_file *file,
 	if (qp->real_qp == qp) {
 		ret = ib_resolve_eth_l2_attrs(qp, attr, &cmd.attr_mask);
 		if (ret)
-			goto out;
+			goto release_qp;
 		ret = qp->device->modify_qp(qp, attr,
 			modify_qp_mask(qp->qp_type, cmd.attr_mask), &udata);
 	} else {
 		ret = ib_modify_qp(qp, attr, modify_qp_mask(qp->qp_type, cmd.attr_mask));
 	}
 
-	put_qp_read(qp);
-
 	if (ret)
-		goto out;
+		goto release_qp;
 
 	ret = in_len;
 
+release_qp:
+	put_qp_read(qp);
+
 out:
 	kfree(attr);
 
-- 
1.7.1

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