On Apr 7, 2014, at 19:45, Devesh Sharma <Devesh.Sharma@xxxxxxxxxx> wrote: > Hi > Inline Below: > > -----Original Message----- > From: Trond Myklebust [mailto:trond.myklebust@xxxxxxxxxxxxxxx] > Sent: Tuesday, April 08, 2014 4:58 AM > To: Devesh Sharma > Cc: linux-nfs@xxxxxxxxxxxxxxx; linux-rdma@xxxxxxxxxxxxxxx > Subject: Re: [PATCH] NFS-RDMA: fix qp pointer validation checks > > > On Apr 7, 2014, at 18:30, devesh.sharma@xxxxxxxxxx wrote: > >> From: Devesh Sharma <devesh.sharma@xxxxxxxxxx> >> >> If the rdma_create_qp fails to create qp due to device firmware being >> in invalid state xprtrdma still tries to destroy the non-existant qp >> and ends up in a NULL pointer reference crash. >> Adding proper checks for vaidating QP pointer avoids this to happen. >> > > As far as I can see, rdma_create_qp() only sets id->qp on success. Otherwise it is left with the same value as it had on entry (i.e. NULL). What am I missing? > [DS]: If you focus on rpcrdma_ep_connect() function and assume that rdma_create_qp() has failed with some valid error code, then this callback function will return ep->rep_connected = some non-zero. > Eventually xprt_rdma_connect_worker() will call rpcrdma_ep_connect() again and rpcrdma_ep_connect will try to free-up all the resources, now rdma_destroy_qp() will be called with invalid QP (which is NULL) pointer > And hence kernel will panic. Please correct me if I am worng. > AFAICS your patch does nothing to address that problem. Instead it adds tests for IS_ERR(ia->ri_id->qp), which can never happen because ia->ri_id->qp is either NULL or points to a valid structure. _________________________________ Trond Myklebust Linux NFS client maintainer, PrimaryData trond.myklebust@xxxxxxxxxxxxxxx -- To unsubscribe from this list: send the line "unsubscribe linux-nfs" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
