This is a note to let you know that I've just added the patch titled

    IB/core: Fix deadlock on uverbs modify_qp error flow

to the 3.19-stable tree which can be found at:
    
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ib-core-fix-deadlock-on-uverbs-modify_qp-error-flow.patch
and it can be found in the queue-3.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <[email protected]> know about it.


>From 0fb8bcf022f19a375d7c4bd79ac513da8ae6d78b Mon Sep 17 00:00:00 2001
From: Moshe Lazer <[email protected]>
Date: Thu, 5 Feb 2015 13:53:52 +0200
Subject: IB/core: Fix deadlock on uverbs modify_qp error flow

From: Moshe Lazer <[email protected]>

commit 0fb8bcf022f19a375d7c4bd79ac513da8ae6d78b upstream.

The deadlock occurs in __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.

Fixes: ed4c54e5b4ba ("IB/core: Resolve Ethernet L2 addresses when modifying QP")
Signed-off-by: Moshe Lazer <[email protected]>
Signed-off-by: Or Gerlitz <[email protected]>
Signed-off-by: Roland Dreier <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

---
 drivers/infiniband/core/uverbs_cmd.c |    9 +++++----
 1 file changed, 5 insertions(+), 4 deletions(-)

--- a/drivers/infiniband/core/uverbs_cmd.c
+++ b/drivers/infiniband/core/uverbs_cmd.c
@@ -2091,20 +2091,21 @@ ssize_t ib_uverbs_modify_qp(struct ib_uv
        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);
 


Patches currently in stable-queue which might be from [email protected] are

queue-3.19/ib-core-fix-deadlock-on-uverbs-modify_qp-error-flow.patch
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