From 6db6dd7d3fd8f7c765dabc376493d6791ab28bd6 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Fri, 4 Jan 2013 12:47:04 -0500 Subject: [PATCH] NFS: Ensure that we free the rpc_task after read and write cleanups are done This patch ensures that we free the rpc_task after the cleanup callbacks are done in order to avoid a deadlock problem that can be triggered if the callback needs to wait for another workqueue item to complete. Signed-off-by: Trond Myklebust Cc: Weston Andros Adamson Cc: Tejun Heo Cc: Bruce Fields Cc: stable@vger.kernel.org [>= 3.5] --- fs/nfs/read.c | 10 +++++++--- fs/nfs/write.c | 10 +++++++--- 2 files changed, 14 insertions(+), 6 deletions(-) diff --git a/fs/nfs/read.c b/fs/nfs/read.c index b6bdb18e892c..a5e5d9899d56 100644 --- a/fs/nfs/read.c +++ b/fs/nfs/read.c @@ -91,12 +91,16 @@ void nfs_readdata_release(struct nfs_read_data *rdata) put_nfs_open_context(rdata->args.context); if (rdata->pages.pagevec != rdata->pages.page_array) kfree(rdata->pages.pagevec); - if (rdata != &read_header->rpc_data) - kfree(rdata); - else + if (rdata == &read_header->rpc_data) { rdata->header = NULL; + rdata = NULL; + } if (atomic_dec_and_test(&hdr->refcnt)) hdr->completion_ops->completion(hdr); + /* Note: we only free the rpc_task after callbacks are done. + * See the comment in rpc_free_task() for why + */ + kfree(rdata); } EXPORT_SYMBOL_GPL(nfs_readdata_release); diff --git a/fs/nfs/write.c b/fs/nfs/write.c index b673be31590e..c483cc50b82e 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -126,12 +126,16 @@ void nfs_writedata_release(struct nfs_write_data *wdata) put_nfs_open_context(wdata->args.context); if (wdata->pages.pagevec != wdata->pages.page_array) kfree(wdata->pages.pagevec); - if (wdata != &write_header->rpc_data) - kfree(wdata); - else + if (wdata == &write_header->rpc_data) { wdata->header = NULL; + wdata = NULL; + } if (atomic_dec_and_test(&hdr->refcnt)) hdr->completion_ops->completion(hdr); + /* Note: we only free the rpc_task after callbacks are done. + * See the comment in rpc_free_task() for why + */ + kfree(wdata); } EXPORT_SYMBOL_GPL(nfs_writedata_release); -- 2.20.1