This is a note to let you know that I've just added the patch titled
rds: rds_ib_device.refcount overflow
to the 4.1-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:
rds-rds_ib_device.refcount-overflow.patch
and it can be found in the queue-4.1 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 4fabb59449aa44a585b3603ffdadd4c5f4d0c033 Mon Sep 17 00:00:00 2001
From: Wengang Wang <wen.gang.wang@xxxxxxxxxx>
Date: Mon, 6 Jul 2015 14:35:11 +0800
Subject: rds: rds_ib_device.refcount overflow
From: Wengang Wang <wen.gang.wang@xxxxxxxxxx>
commit 4fabb59449aa44a585b3603ffdadd4c5f4d0c033 upstream.
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@xxxxxxxxxx>
Reviewed-by: Haggai Eran <haggaie@xxxxxxxxxxxx>
Signed-off-by: Doug Ledford <dledford@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
net/rds/ib_rdma.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
--- a/net/rds/ib_rdma.c
+++ b/net/rds/ib_rdma.c
@@ -759,8 +759,10 @@ void *rds_ib_get_mr(struct scatterlist *
}
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)
Patches currently in stable-queue which might be from wen.gang.wang@xxxxxxxxxx are
queue-4.1/rds-rds_ib_device.refcount-overflow.patch
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