From 8aca67f0ae2d8811165c22326825a645cc8e1b48 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Mon, 13 Nov 2006 16:23:44 -0500 Subject: SUNRPC: Fix a potential race in rpc_wake_up_task() Use RCU to ensure that we can safely call rpc_finish_wakeup after we've called __rpc_do_wake_up_task. If not, there is a theoretical race, in which the rpc_task finishes executing, and gets freed first. Signed-off-by: Trond Myklebust --- fs/nfs/read.c | 8 +++++++- fs/nfs/write.c | 20 ++++++++++++++++---- 2 files changed, 23 insertions(+), 5 deletions(-) (limited to 'fs/nfs') diff --git a/fs/nfs/read.c b/fs/nfs/read.c index c2e49c397a2..8b58bbf6e39 100644 --- a/fs/nfs/read.c +++ b/fs/nfs/read.c @@ -65,13 +65,19 @@ struct nfs_read_data *nfs_readdata_alloc(size_t len) return p; } -static void nfs_readdata_free(struct nfs_read_data *p) +static void nfs_readdata_rcu_free(struct rcu_head *head) { + struct nfs_read_data *p = container_of(head, struct nfs_read_data, task.u.tk_rcu); if (p && (p->pagevec != &p->page_array[0])) kfree(p->pagevec); mempool_free(p, nfs_rdata_mempool); } +static void nfs_readdata_free(struct nfs_read_data *rdata) +{ + call_rcu_bh(&rdata->task.u.tk_rcu, nfs_readdata_rcu_free); +} + void nfs_readdata_release(void *data) { nfs_readdata_free(data); diff --git a/fs/nfs/write.c b/fs/nfs/write.c index 883dd4a1c15..29d88209199 100644 --- a/fs/nfs/write.c +++ b/fs/nfs/write.c @@ -102,13 +102,19 @@ struct nfs_write_data *nfs_commit_alloc(void) return p; } -void nfs_commit_free(struct nfs_write_data *p) +void nfs_commit_rcu_free(struct rcu_head *head) { + struct nfs_write_data *p = container_of(head, struct nfs_write_data, task.u.tk_rcu); if (p && (p->pagevec != &p->page_array[0])) kfree(p->pagevec); mempool_free(p, nfs_commit_mempool); } +void nfs_commit_free(struct nfs_write_data *wdata) +{ + call_rcu_bh(&wdata->task.u.tk_rcu, nfs_commit_rcu_free); +} + struct nfs_write_data *nfs_writedata_alloc(size_t len) { unsigned int pagecount = (len + PAGE_SIZE - 1) >> PAGE_SHIFT; @@ -131,13 +137,19 @@ struct nfs_write_data *nfs_writedata_alloc(size_t len) return p; } -static void nfs_writedata_free(struct nfs_write_data *p) +static void nfs_writedata_rcu_free(struct rcu_head *head) { + struct nfs_write_data *p = container_of(head, struct nfs_write_data, task.u.tk_rcu); if (p && (p->pagevec != &p->page_array[0])) kfree(p->pagevec); mempool_free(p, nfs_wdata_mempool); } +static void nfs_writedata_free(struct nfs_write_data *wdata) +{ + call_rcu_bh(&wdata->task.u.tk_rcu, nfs_writedata_rcu_free); +} + void nfs_writedata_release(void *wdata) { nfs_writedata_free(wdata); @@ -258,7 +270,7 @@ static int nfs_writepage_sync(struct nfs_open_context *ctx, struct inode *inode, io_error: nfs_end_data_update(inode); end_page_writeback(page); - nfs_writedata_free(wdata); + nfs_writedata_release(wdata); return written ? written : result; } @@ -1043,7 +1055,7 @@ out_bad: while (!list_empty(&list)) { data = list_entry(list.next, struct nfs_write_data, pages); list_del(&data->pages); - nfs_writedata_free(data); + nfs_writedata_release(data); } nfs_mark_request_dirty(req); nfs_clear_page_writeback(req); -- cgit v1.2.3