From 506026c3ec270e18402f0c9d33fee37482c23861 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Mon, 23 Jul 2012 15:51:55 -0400 Subject: sunrpc: clarify comments on rpc_make_runnable rpc_make_runnable is not generally called with the queue lock held, unless it's waking up a task that has been sitting on a waitqueue. This is safe when the task has not entered the FSM yet, but the comments don't really spell this out. Signed-off-by: Jeff Layton Signed-off-by: Trond Myklebust --- net/sunrpc/sched.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-) (limited to 'net') diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c index 994cfea2bad6..ada1e2c33aa4 100644 --- a/net/sunrpc/sched.c +++ b/net/sunrpc/sched.c @@ -300,8 +300,9 @@ EXPORT_SYMBOL_GPL(__rpc_wait_for_completion_task); /* * Make an RPC task runnable. * - * Note: If the task is ASYNC, this must be called with - * the spinlock held to protect the wait queue operation. + * Note: If the task is ASYNC, and is being made runnable after sitting on an + * rpc_wait_queue, this must be called with the queue spinlock held to protect + * the wait queue operation. */ static void rpc_make_runnable(struct rpc_task *task) { -- cgit v1.2.3-70-g09d2 From 5cf02d09b50b1ee1c2d536c9cf64af5a7d433f56 Mon Sep 17 00:00:00 2001 From: Jeff Layton Date: Mon, 23 Jul 2012 13:58:51 -0400 Subject: nfs: skip commit in releasepage if we're freeing memory for fs-related reasons We've had some reports of a deadlock where rpciod ends up with a stack trace like this: PID: 2507 TASK: ffff88103691ab40 CPU: 14 COMMAND: "rpciod/14" #0 [ffff8810343bf2f0] schedule at ffffffff814dabd9 #1 [ffff8810343bf3b8] nfs_wait_bit_killable at ffffffffa038fc04 [nfs] #2 [ffff8810343bf3c8] __wait_on_bit at ffffffff814dbc2f #3 [ffff8810343bf418] out_of_line_wait_on_bit at ffffffff814dbcd8 #4 [ffff8810343bf488] nfs_commit_inode at ffffffffa039e0c1 [nfs] #5 [ffff8810343bf4f8] nfs_release_page at ffffffffa038bef6 [nfs] #6 [ffff8810343bf528] try_to_release_page at ffffffff8110c670 #7 [ffff8810343bf538] shrink_page_list.clone.0 at ffffffff81126271 #8 [ffff8810343bf668] shrink_inactive_list at ffffffff81126638 #9 [ffff8810343bf818] shrink_zone at ffffffff8112788f #10 [ffff8810343bf8c8] do_try_to_free_pages at ffffffff81127b1e #11 [ffff8810343bf958] try_to_free_pages at ffffffff8112812f #12 [ffff8810343bfa08] __alloc_pages_nodemask at ffffffff8111fdad #13 [ffff8810343bfb28] kmem_getpages at ffffffff81159942 #14 [ffff8810343bfb58] fallback_alloc at ffffffff8115a55a #15 [ffff8810343bfbd8] ____cache_alloc_node at ffffffff8115a2d9 #16 [ffff8810343bfc38] kmem_cache_alloc at ffffffff8115b09b #17 [ffff8810343bfc78] sk_prot_alloc at ffffffff81411808 #18 [ffff8810343bfcb8] sk_alloc at ffffffff8141197c #19 [ffff8810343bfce8] inet_create at ffffffff81483ba6 #20 [ffff8810343bfd38] __sock_create at ffffffff8140b4a7 #21 [ffff8810343bfd98] xs_create_sock at ffffffffa01f649b [sunrpc] #22 [ffff8810343bfdd8] xs_tcp_setup_socket at ffffffffa01f6965 [sunrpc] #23 [ffff8810343bfe38] worker_thread at ffffffff810887d0 #24 [ffff8810343bfee8] kthread at ffffffff8108dd96 #25 [ffff8810343bff48] kernel_thread at ffffffff8100c1ca rpciod is trying to allocate memory for a new socket to talk to the server. The VM ends up calling ->releasepage to get more memory, and it tries to do a blocking commit. That commit can't succeed however without a connected socket, so we deadlock. Fix this by setting PF_FSTRANS on the workqueue task prior to doing the socket allocation, and having nfs_release_page check for that flag when deciding whether to do a commit call. Also, set PF_FSTRANS unconditionally in rpc_async_schedule since that function can also do allocations sometimes. Signed-off-by: Jeff Layton Signed-off-by: Trond Myklebust Cc: stable@vger.kernel.org --- fs/nfs/file.c | 7 +++++-- net/sunrpc/sched.c | 2 ++ net/sunrpc/xprtrdma/transport.c | 3 ++- net/sunrpc/xprtsock.c | 10 ++++++++++ 4 files changed, 19 insertions(+), 3 deletions(-) (limited to 'net') diff --git a/fs/nfs/file.c b/fs/nfs/file.c index 70d124a61b98..1b3925426929 100644 --- a/fs/nfs/file.c +++ b/fs/nfs/file.c @@ -447,8 +447,11 @@ static int nfs_release_page(struct page *page, gfp_t gfp) dfprintk(PAGECACHE, "NFS: release_page(%p)\n", page); - /* Only do I/O if gfp is a superset of GFP_KERNEL */ - if (mapping && (gfp & GFP_KERNEL) == GFP_KERNEL) { + /* Only do I/O if gfp is a superset of GFP_KERNEL, and we're not + * doing this memory reclaim for a fs-related allocation. + */ + if (mapping && (gfp & GFP_KERNEL) == GFP_KERNEL && + !(current->flags & PF_FSTRANS)) { int how = FLUSH_SYNC; /* Don't let kswapd deadlock waiting for OOM RPC calls */ diff --git a/net/sunrpc/sched.c b/net/sunrpc/sched.c index ada1e2c33aa4..1f19aa15f89b 100644 --- a/net/sunrpc/sched.c +++ b/net/sunrpc/sched.c @@ -791,7 +791,9 @@ void rpc_execute(struct rpc_task *task) static void rpc_async_schedule(struct work_struct *work) { + current->flags |= PF_FSTRANS; __rpc_execute(container_of(work, struct rpc_task, u.tk_work)); + current->flags &= ~PF_FSTRANS; } /** diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c index b446e100286f..06cdbff79e4a 100644 --- a/net/sunrpc/xprtrdma/transport.c +++ b/net/sunrpc/xprtrdma/transport.c @@ -200,6 +200,7 @@ xprt_rdma_connect_worker(struct work_struct *work) int rc = 0; if (!xprt->shutdown) { + current->flags |= PF_FSTRANS; xprt_clear_connected(xprt); dprintk("RPC: %s: %sconnect\n", __func__, @@ -212,10 +213,10 @@ xprt_rdma_connect_worker(struct work_struct *work) out: xprt_wake_pending_tasks(xprt, rc); - out_clear: dprintk("RPC: %s: exit\n", __func__); xprt_clear_connecting(xprt); + current->flags &= ~PF_FSTRANS; } /* diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index 890b03f8d877..b88c6bf657ba 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -1895,6 +1895,8 @@ static void xs_local_setup_socket(struct work_struct *work) if (xprt->shutdown) goto out; + current->flags |= PF_FSTRANS; + clear_bit(XPRT_CONNECTION_ABORT, &xprt->state); status = __sock_create(xprt->xprt_net, AF_LOCAL, SOCK_STREAM, 0, &sock, 1); @@ -1928,6 +1930,7 @@ static void xs_local_setup_socket(struct work_struct *work) out: xprt_clear_connecting(xprt); xprt_wake_pending_tasks(xprt, status); + current->flags &= ~PF_FSTRANS; } static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock) @@ -1970,6 +1973,8 @@ static void xs_udp_setup_socket(struct work_struct *work) if (xprt->shutdown) goto out; + current->flags |= PF_FSTRANS; + /* Start by resetting any existing state */ xs_reset_transport(transport); sock = xs_create_sock(xprt, transport, @@ -1988,6 +1993,7 @@ static void xs_udp_setup_socket(struct work_struct *work) out: xprt_clear_connecting(xprt); xprt_wake_pending_tasks(xprt, status); + current->flags &= ~PF_FSTRANS; } /* @@ -2113,6 +2119,8 @@ static void xs_tcp_setup_socket(struct work_struct *work) if (xprt->shutdown) goto out; + current->flags |= PF_FSTRANS; + if (!sock) { clear_bit(XPRT_CONNECTION_ABORT, &xprt->state); sock = xs_create_sock(xprt, transport, @@ -2162,6 +2170,7 @@ static void xs_tcp_setup_socket(struct work_struct *work) case -EINPROGRESS: case -EALREADY: xprt_clear_connecting(xprt); + current->flags &= ~PF_FSTRANS; return; case -EINVAL: /* Happens, for instance, if the user specified a link @@ -2174,6 +2183,7 @@ out_eagain: out: xprt_clear_connecting(xprt); xprt_wake_pending_tasks(xprt, status); + current->flags &= ~PF_FSTRANS; } /** -- cgit v1.2.3-70-g09d2 From caea33da898e4e14f0ba58173e3b7689981d2c0b Mon Sep 17 00:00:00 2001 From: Stanislav Kinsbursky Date: Fri, 20 Jul 2012 15:57:48 +0400 Subject: SUNRPC: return negative value in case rpcbind client creation error Without this patch kernel will panic on LockD start, because lockd_up() checks lockd_up_net() result for negative value. From my pow it's better to return negative value from rpcbind routines instead of replacing all such checks like in lockd_up(). Signed-off-by: Stanislav Kinsbursky Signed-off-by: Trond Myklebust Cc: stable@vger.kernel.org [>= 3.0] --- net/sunrpc/rpcb_clnt.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net') diff --git a/net/sunrpc/rpcb_clnt.c b/net/sunrpc/rpcb_clnt.c index 92509ffe15fc..a70acae496e4 100644 --- a/net/sunrpc/rpcb_clnt.c +++ b/net/sunrpc/rpcb_clnt.c @@ -251,7 +251,7 @@ static int rpcb_create_local_unix(struct net *net) if (IS_ERR(clnt)) { dprintk("RPC: failed to create AF_LOCAL rpcbind " "client (errno %ld).\n", PTR_ERR(clnt)); - result = -PTR_ERR(clnt); + result = PTR_ERR(clnt); goto out; } @@ -298,7 +298,7 @@ static int rpcb_create_local_net(struct net *net) if (IS_ERR(clnt)) { dprintk("RPC: failed to create local rpcbind " "client (errno %ld).\n", PTR_ERR(clnt)); - result = -PTR_ERR(clnt); + result = PTR_ERR(clnt); goto out; } -- cgit v1.2.3-70-g09d2