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[142.162.113.180]) by smtp.gmail.com with ESMTPSA id z17sm1480301qtj.95.2019.10.25.05.34.54 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 25 Oct 2019 05:34:54 -0700 (PDT) Received: from jgg by mlx.ziepe.ca with local (Exim 4.90_1) (envelope-from ) id 1iNynu-0004zW-3m; Fri, 25 Oct 2019 09:34:54 -0300 Date: Fri, 25 Oct 2019 09:34:54 -0300 From: Jason Gunthorpe To: Bernard Metzler Cc: Dan Carpenter , Doug Ledford , linux-rdma@vger.kernel.org Subject: Re: [bug report] RDMA/siw: Fix SQ/RQ drain logic Message-ID: <20191025123454.GH23952@ziepe.ca> References: <20191024203841.GA7912@mwanda> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On Fri, Oct 25, 2019 at 08:16:15AM +0000, Bernard Metzler wrote: > > >To: bmt@zurich.ibm.com > >From: "Dan Carpenter" > >Date: 10/24/2019 10:39PM > >Cc: linux-rdma@vger.kernel.org > >Subject: [EXTERNAL] [bug report] RDMA/siw: Fix SQ/RQ drain logic > > > >Hello Bernard Metzler, > > > >The patch cf049bb31f71: "RDMA/siw: Fix SQ/RQ drain logic" from Oct 4, > >2019, leads to the following static checker warning: > > > > drivers/infiniband/sw/siw/siw_verbs.c:1079 siw_post_receive() > > error: locking inconsistency. We assume 'read_sem:&qp->state_lock' > >is both locked and unlocked at the start. > > > >drivers/infiniband/sw/siw/siw_verbs.c > > 978 int siw_post_receive(struct ib_qp *base_qp, const struct > >ib_recv_wr *wr, > > 979 const struct ib_recv_wr **bad_wr) > > 980 { > > 981 struct siw_qp *qp = to_siw_qp(base_qp); > > 982 unsigned long flags; > > 983 int rv = 0; > > 984 > > 985 if (qp->srq) { > > 986 *bad_wr = wr; > > 987 return -EOPNOTSUPP; /* what else from > >errno.h? */ > > 988 } > > 989 if (!qp->kernel_verbs) { > > 990 siw_dbg_qp(qp, "no kernel post_recv for user > >mapped sq\n"); > > 991 up_read(&qp->state_lock); > > ^^^^^^^^^^^^^^^^^^^^^^^^ > >The patch changes the locking so this isn't held here and should be > >released. Should it be held, though? > > Yes, this is a BUG. Thanks very much! There is no qp spinlock to > be held here. I moved that down to state checking. No need to > hold the qp lock before. > > Shall I re-send, or can we just amend the patch, > removing that single 'up_read()' line? You need to send a new patch against for-next to fix this Jason