Messages in this thread Patch in this message | | | Date | Sun, 29 May 2005 15:31:02 +0400 | From | Oleg Nesterov <> | Subject | Re: RT and Cascade interrupts |
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__rpc_execute() calls ->tk_exit and goes to 'restarted' label. What if ->tk_exit calls rpc_sleep_on() ? If it is possible, we have a race.
CPU_0 (main loop in rpc_execute restarted) CPU_1
rpc_delete_timer: if (RPC_IS_QUEUED()) // YES return; rpc_run_timer: rpc_wake_up_task: clear_bit(RPC_TASK_QUEUED) preemption, or long interrupt
if (!RPC_IS_QUEUED()) // YES task->tk_action() __rpc_add_timer: set_bit(RPC_TASK_HAS_TIMER) mod_timer(); clear_bit(RPC_TASK_HAS_TIMER)
Now we have pending timer without RPC_TASK_HAS_TIMER bit set.
Is this patch makes any sense?
Oleg.
--- 2.6.12-rc5/net/sunrpc/sched.c~ Sun May 29 15:09:25 2005 +++ 2.6.12-rc5/net/sunrpc/sched.c Sun May 29 15:11:24 2005 @@ -135,8 +135,6 @@ __rpc_add_timer(struct rpc_task *task, r static void rpc_delete_timer(struct rpc_task *task) { - if (RPC_IS_QUEUED(task)) - return; if (test_and_clear_bit(RPC_TASK_HAS_TIMER, &task->tk_runstate)) { del_singleshot_timer_sync(&task->tk_timer); dprintk("RPC: %4d deleting timer\n", task->tk_pid); @@ -566,7 +564,6 @@ static int __rpc_execute(struct rpc_task BUG_ON(RPC_IS_QUEUED(task)); - restarted: while (1) { /* * Garbage collection of pending timers... @@ -607,6 +604,7 @@ static int __rpc_execute(struct rpc_task unlock_kernel(); } + restarted: /* * Lockless check for whether task is sleeping or not. */ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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