[ewg] Re: [ofa-general] [PATCH] IB/ipoib: fix net queue lockup

[Roland Dreier]

thanks, looks like a good solution, applied, just adding an ipoib_
prefix since

 > +void send_comp_handler(struct ib_cq *cq, void *dev_ptr)

is too generic a name for a global symbol.

By the way I figured out the crash on unload -- it was an mlx4 bug that
I introduced, which is fixed by:


IB/mlx4: Fix off-by-one errors in calls to mlx4_ib_free_cq_buf()

When I merged bbf8eed1 ("IB/mlx4: Add support for resizing CQs") I
changed things around so that mlx4_ib_alloc_cq_buf() and
mlx4_ib_free_cq_buf() were used everywhere they could be.  However, I
screwed up the number of entries passed into mlx4_ib_alloc_cq_buf()
in a couple places -- the function bumps the number of entries
internally, so the caller shouldn't add 1 as well.

Passing a too-big value for the number of entries to mlx4_ib_free_cq_buf()
can cause the cleanup to go off the end of an array and corrupt
allocator state in interesting ways.

Signed-off-by: Roland Dreier <rolandd at cisco.com>
---
 drivers/infiniband/hw/mlx4/cq.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/infiniband/hw/mlx4/cq.c b/drivers/infiniband/hw/mlx4/cq.c
index 2f199c5..4521319 100644
--- a/drivers/infiniband/hw/mlx4/cq.c
+++ b/drivers/infiniband/hw/mlx4/cq.c
@@ -246,7 +246,7 @@ err_mtt:
 	if (context)
 		ib_umem_release(cq->umem);
 	else
-		mlx4_ib_free_cq_buf(dev, &cq->buf, entries);
+		mlx4_ib_free_cq_buf(dev, &cq->buf, cq->ibcq.cqe);
 
 err_db:
 	if (!context)
@@ -434,7 +434,7 @@ int mlx4_ib_destroy_cq(struct ib_cq *cq)
 		mlx4_ib_db_unmap_user(to_mucontext(cq->uobject->context), &mcq->db);
 		ib_umem_release(mcq->umem);
 	} else {
-		mlx4_ib_free_cq_buf(dev, &mcq->buf, cq->cqe + 1);
+		mlx4_ib_free_cq_buf(dev, &mcq->buf, cq->cqe);
 		mlx4_db_free(dev->dev, &mcq->db);
 	}
 
-- 
1.5.5.1