From 875f0706accd6501c3209bb99df8573171fb5d75 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Thu, 17 Oct 2019 09:02:19 -0400 Subject: SUNRPC: The TCP back channel mustn't disappear while requests are outstanding If there are TCP back channel requests being processed by the server threads, then we should hold a reference to the transport to ensure it doesn't get freed from underneath us. Reported-by: Neil Brown Fixes: 2ea24497a1b3 ("SUNRPC: RPC callbacks may be split across several..") Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker --- net/sunrpc/backchannel_rqst.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'net/sunrpc/backchannel_rqst.c') diff --git a/net/sunrpc/backchannel_rqst.c b/net/sunrpc/backchannel_rqst.c index 339e8c077c2d..7eb251372f94 100644 --- a/net/sunrpc/backchannel_rqst.c +++ b/net/sunrpc/backchannel_rqst.c @@ -307,8 +307,8 @@ void xprt_free_bc_rqst(struct rpc_rqst *req) */ dprintk("RPC: Last session removed req=%p\n", req); xprt_free_allocation(req); - return; } + xprt_put(xprt); } /* @@ -339,7 +339,7 @@ found: spin_unlock(&xprt->bc_pa_lock); if (new) { if (req != new) - xprt_free_bc_rqst(new); + xprt_free_allocation(new); break; } else if (req) break; @@ -368,6 +368,7 @@ void xprt_complete_bc_request(struct rpc_rqst *req, uint32_t copied) set_bit(RPC_BC_PA_IN_USE, &req->rq_bc_pa_state); dprintk("RPC: add callback request to list\n"); + xprt_get(xprt); spin_lock(&bc_serv->sv_cb_lock); list_add(&req->rq_bc_list, &bc_serv->sv_cb_list); wake_up(&bc_serv->sv_cb_waitq); -- cgit v1.2.3 From 669996add4c92476e0f8d6b4cd2bb308d1939fd7 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Thu, 17 Oct 2019 09:02:21 -0400 Subject: SUNRPC: Destroy the back channel when we destroy the host transport When we're destroying the host transport mechanism, we should ensure that we do not leak memory by failing to release any back channel slots that might still exist. Reported-by: Neil Brown Reported-by: kbuild test robot Signed-off-by: Trond Myklebust Signed-off-by: Anna Schumaker --- include/linux/sunrpc/bc_xprt.h | 5 +++++ net/sunrpc/backchannel_rqst.c | 2 +- net/sunrpc/xprt.c | 5 +++++ 3 files changed, 11 insertions(+), 1 deletion(-) (limited to 'net/sunrpc/backchannel_rqst.c') diff --git a/include/linux/sunrpc/bc_xprt.h b/include/linux/sunrpc/bc_xprt.h index 87d27e13d885..d796058cdff2 100644 --- a/include/linux/sunrpc/bc_xprt.h +++ b/include/linux/sunrpc/bc_xprt.h @@ -64,6 +64,11 @@ static inline int xprt_setup_backchannel(struct rpc_xprt *xprt, return 0; } +static inline void xprt_destroy_backchannel(struct rpc_xprt *xprt, + unsigned int max_reqs) +{ +} + static inline bool svc_is_backchannel(const struct svc_rqst *rqstp) { return false; diff --git a/net/sunrpc/backchannel_rqst.c b/net/sunrpc/backchannel_rqst.c index 7eb251372f94..195b40c5dae4 100644 --- a/net/sunrpc/backchannel_rqst.c +++ b/net/sunrpc/backchannel_rqst.c @@ -220,7 +220,7 @@ void xprt_destroy_bc(struct rpc_xprt *xprt, unsigned int max_reqs) goto out; spin_lock_bh(&xprt->bc_pa_lock); - xprt->bc_alloc_max -= max_reqs; + xprt->bc_alloc_max -= min(max_reqs, xprt->bc_alloc_max); list_for_each_entry_safe(req, tmp, &xprt->bc_pa_list, rq_bc_pa_list) { dprintk("RPC: req=%p\n", req); list_del(&req->rq_bc_pa_list); diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index 8a45b3ccc313..41df4c507193 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -1942,6 +1942,11 @@ static void xprt_destroy_cb(struct work_struct *work) rpc_destroy_wait_queue(&xprt->sending); rpc_destroy_wait_queue(&xprt->backlog); kfree(xprt->servername); + /* + * Destroy any existing back channel + */ + xprt_destroy_backchannel(xprt, UINT_MAX); + /* * Tear down transport state and free the rpc_xprt */ -- cgit v1.2.3