From 4fabb59449aa44a585b3603ffdadd4c5f4d0c033 Mon Sep 17 00:00:00 2001
From: Wengang Wang <wen.gang.wang@oracle.com>
Date: Mon, 6 Jul 2015 14:35:11 +0800
Subject: rds: rds_ib_device.refcount overflow
Fixes: 3e0249f9c05c ("RDS/IB: add refcount tracking to struct rds_ib_device")
There lacks a dropping on rds_ib_device.refcount in case rds_ib_alloc_fmr
failed(mr pool running out). this lead to the refcount overflow.
A complain in line 117(see following) is seen. From vmcore:
s_ib_rdma_mr_pool_depleted is 2147485544 and rds_ibdev->refcount is -2147475448.
That is the evidence the mr pool is used up. so rds_ib_alloc_fmr is very likely
to return ERR_PTR(-EAGAIN).
115 void rds_ib_dev_put(struct rds_ib_device *rds_ibdev)
116 {
117 BUG_ON(atomic_read(&rds_ibdev->refcount) <= 0);
118 if (atomic_dec_and_test(&rds_ibdev->refcount))
119 queue_work(rds_wq, &rds_ibdev->free_work);
120 }
fix is to drop refcount when rds_ib_alloc_fmr failed.
Signed-off-by: Wengang Wang <wen.gang.wang@oracle.com>
Reviewed-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
---
net/rds/ib_rdma.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/net/rds/ib_rdma.c b/net/rds/ib_rdma.c
index 273b8bff6ba4..657ba9f5d308 100644
--- a/net/rds/ib_rdma.c
+++ b/net/rds/ib_rdma.c
@@ -759,8 +759,10 @@ void *rds_ib_get_mr(struct scatterlist *sg, unsigned long nents,
}
ibmr = rds_ib_alloc_fmr(rds_ibdev);
- if (IS_ERR(ibmr))
+ if (IS_ERR(ibmr)) {
+ rds_ib_dev_put(rds_ibdev);
return ibmr;
+ }
ret = rds_ib_map_fmr(rds_ibdev, ibmr, sg, nents);
if (ret == 0)
--
cgit