]> www.infradead.org Git - users/jedix/linux-maple.git/commit
rds: rds_ib_device.refcount overflow
authorWengang Wang <wen.gang.wang@oracle.com>
Mon, 6 Jul 2015 06:35:11 +0000 (14:35 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Mon, 10 Aug 2015 19:21:57 +0000 (12:21 -0700)
commitf3ef6ad3e4501dae41b0015a3bd8e179b56bdfd8
treec135af6956b461a9e83e29ee1aec8094ac7db2fb
parent26121b675728939c515594b2bb866756b7789c16
rds: rds_ib_device.refcount overflow

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@oracle.com>
Reviewed-by: Haggai Eran <haggaie@mellanox.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
net/rds/ib_rdma.c