On Thu, Dec 05, 2019 at 11:40:04AM +0300, Vasily Averin wrote: > I've found that Trond fixed it recently in commit 875f0706acc > "SUNRPC: The TCP back channel mustn't disappear while requests are outstanding" Thanks for following up!--b. > > On 11/29/19 5:10 PM, Vasily Averin wrote: > >OpenVz team got complain on crash in bc_svc_process(). > >Crashed node had 15 running containers with active nfsv4.1 mounts, > >single nfsv4.1-svc thread was processed its back-channel requests. > >In our case nfs41_callback_svc() took rpc_rqst *req from serv->sv_cb_list > >started its processing but found that req->rq_xprt points to already freed > >struct rpc_xprt aka part of struct sock_xprt transport. > > > >Back-channel request was submitted via xprt_complete_bc_request(), > >its processing uses req->rq_xprt reference in many times, > >however I did not found who keeps this reference. > >It seems sock_xprt or even whole its net namespace can be freed before bc_svc_process() will start processing of submitted back-channel request, and req->rq_xprt using is unsafe in bc_svc_process() > > > >Am I missed something probably?
