Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2993389AbbHHW2u (ORCPT ); Sat, 8 Aug 2015 18:28:50 -0400 Received: from mail.linuxfoundation.org ([140.211.169.12]:36514 "EHLO mail.linuxfoundation.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2993144AbbHHWSJ (ORCPT ); Sat, 8 Aug 2015 18:18:09 -0400 From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Wengang Wang , Haggai Eran , Doug Ledford Subject: [PATCH 4.1 096/123] rds: rds_ib_device.refcount overflow Date: Sat, 8 Aug 2015 15:09:34 -0700 Message-Id: <20150808220721.064060105@linuxfoundation.org> X-Mailer: git-send-email 2.5.0 In-Reply-To: <20150808220717.771230091@linuxfoundation.org> References: <20150808220717.771230091@linuxfoundation.org> User-Agent: quilt/0.64 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1843 Lines: 57 4.1-stable review patch. If anyone has any objections, please let me know. ------------------ From: Wengang Wang 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 Reviewed-by: Haggai Eran Signed-off-by: Doug Ledford Signed-off-by: Greg Kroah-Hartman --- 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) -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/