Re: RT and Cascade interrupts

john cooper
2005-05-30T21:35:49Z

Trond Myklebust wrote:

> I've appended a patch that
> should check for strict compliance of the above rules. Could you try it
> out and see if it triggers any Oopses?

Yes, the assert in rpc_delete_timer() occurs just before
the cascade list corruption. This is consistent with
what I have seen. ie: the timer in a released rpc_task
is still active.

BTW, the patch from Oleg is relative to 2.6.12 and didn't
look to apply to the 2.6.11-derived base with which I'm
working (the RPC_IS_QUEUED() test at the head of rpc_delete_timer()
does not exist). In any case the relocation of restarted: in
__rpc_execute() did not influence the failure. I'd like to
move to a 2.6.12-based -RT patch however I'm dealing with
"code in the pipe" and unfortunately don't have that option.

Sorry I'm just responding new. We're in the middle of a
long holiday weekend. I will have more time come tomorrow
to analyze this further.

-john

> ------------------------------------------------------------------------
>
> sched.c | 8 ++++++++
> 1 files changed, 8 insertions(+)
>
> Index: linux-2.6.12-rc4/net/sunrpc/sched.c
> ===================================================================
> --- linux-2.6.12-rc4.orig/net/sunrpc/sched.c
> +++ linux-2.6.12-rc4/net/sunrpc/sched.c
> @@ -135,6 +135,8 @@ __rpc_add_timer(struct rpc_task *task, r
> static void
> rpc_delete_timer(struct rpc_task *task)
> {
> + BUG_ON(test_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate) == 0 &&
> + timer_pending(&task->tk_timer));
> if (RPC_IS_QUEUED(task))
> return;
> if (test_and_clear_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate)) {
> @@ -337,6 +339,8 @@ static void __rpc_sleep_on(struct rpc_wa
> void rpc_sleep_on(struct rpc_wait_queue *q, struct rpc_task *task,
> rpc_action action, rpc_action timer)
> {
> + BUG_ON(test_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate) != 0 ||
> + timer_pending(&task->tk_timer));
> /*
> * Protect the queue operations.
> */
> @@ -594,6 +598,8 @@ static int __rpc_execute(struct rpc_task
> unlock_kernel();
> }
>
> + BUG_ON(test_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate) != 0 ||
> + timer_pending(&task->tk_timer));
> /*
> * Perform the next FSM step.
> * tk_action may be NULL when the task has been killed
> @@ -925,6 +931,8 @@ fail:
>
> void rpc_run_child(struct rpc_task *task, struct rpc_task *child, rpc_action func)
> {
> + BUG_ON(test_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate) != 0 ||
> + timer_pending(&task->tk_timer));
> spin_lock_bh(&childq.lock);
> /* N.B. Is it possible for the child to have already finished? */
> __rpc_sleep_on(&childq, task, func, NULL);

--
john.cooper@timesys.com