| From | Andi Kleen <> | Subject | [PATCH] [209/275] SUNRPC: Ensure we always run the tk_callback before tk_action | Date | Wed, 30 Mar 2011 14:07:33 -0700 (PDT) |
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2.6.35-longterm review patch. If anyone has any objections, please let me know.
------------------ From: Trond Myklebust <Trond.Myklebust@netapp.com>
commit e020c6800c9621a77223bf2c1ff68180e41e8ebf upstream.
This fixes a race in which the task->tk_callback() puts the rpc_task to sleep, setting a new callback. Under certain circumstances, the current code may end up executing the task->tk_action before it gets round to the callback.
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de> Signed-off-by: Andi Kleen <ak@linux.intel.com>
--- net/sunrpc/sched.c | 14 ++++++-------- 1 file changed, 6 insertions(+), 8 deletions(-)
Index: linux-2.6.35.y/net/sunrpc/sched.c =================================================================== --- linux-2.6.35.y.orig/net/sunrpc/sched.c 2011-03-29 22:50:35.157358829 -0700 +++ linux-2.6.35.y/net/sunrpc/sched.c 2011-03-29 23:03:02.613233304 -0700 @@ -637,14 +637,12 @@ save_callback = task->tk_callback; task->tk_callback = NULL; save_callback(task); - } - - /* - * Perform the next FSM step. - * tk_action may be NULL when the task has been killed - * by someone else. - */ - if (!RPC_IS_QUEUED(task)) { + } else { + /* + * Perform the next FSM step. + * tk_action may be NULL when the task has been killed + * by someone else. + */ if (task->tk_action == NULL) break; task->tk_action(task);
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