From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wengang Wang Subject: Re: [PATCH] rds: rds_ib_device.refcount overflow Date: Thu, 30 Jul 2015 13:35:09 +0800 Message-ID: <55B9B78D.5000807@oracle.com> References: <1436164511-2411-1-git-send-email-wen.gang.wang@oracle.com> <55A31202.1030408@oracle.com> <55B8E4F2.2060700@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: In-Reply-To: <55B8E4F2.2060700-H+wXaHxf7aLQT0dZR+AlfA@public.gmane.org> Sender: linux-rdma-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Doug Ledford Cc: haggaie-VPRAkNaXOzVWk0Htik3J/w@public.gmane.org, linux-rdma-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-rdma@vger.kernel.org Doug, No problem. I found the patch picked up. thanks, wengang =E5=9C=A8 2015=E5=B9=B407=E6=9C=8829=E6=97=A5 22:36, Doug Ledford =E5=86= =99=E9=81=93: > On 07/12/2015 09:18 PM, Wengang Wang wrote: >> Hi Doug, >> >> How do you think about this patch? > Sorry, I picked this up already. I must have missed sending out the > acknowledgment on this one. > >> thanks, >> wengang >> >> =E5=9C=A8 2015=E5=B9=B407=E6=9C=8806=E6=97=A5 14:35, Wengang Wang =E5= =86=99=E9=81=93: >>> 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_all= oc_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) <=3D 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 >>> Reviewed-by: Haggai Eran >>> --- >>> 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 273b8bf..657ba9f 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 =3D rds_ib_alloc_fmr(rds_ibdev); >>> - if (IS_ERR(ibmr)) >>> + if (IS_ERR(ibmr)) { >>> + rds_ib_dev_put(rds_ibdev); >>> return ibmr; >>> + } >>> ret =3D rds_ib_map_fmr(rds_ibdev, ibmr, sg, nents); >>> if (ret =3D=3D 0) >> --=20 >> To unsubscribe from this list: send the line "unsubscribe linux-rdma= " in >> the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-rdma" i= n the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html