e24f281401
The three fixes are to handle cases in the SMP configuration where one CPU does need to make modifications to TCB and data structures on a task that could be running running on another CPU. Those three cases are task_delete(), task_restart(), and execution of signal handles. In all three cases the solutions is basically the same: (1) Call sched_cpu_pause(tcb) to pause the CPU on which the task is running, (2) perform the necessary operations, then (3) call up_cpu_resume() to restart the paused CPU.
208 lines
6.8 KiB
C
208 lines
6.8 KiB
C
/****************************************************************************
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* sched/task/task_terminate.c
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*
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* Copyright (C) 2007-2009, 2011-2014, 2016 Gregory Nutt. All rights reserved.
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* Author: Gregory Nutt <gnutt@nuttx.org>
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*
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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*
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in
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* the documentation and/or other materials provided with the
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* distribution.
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* 3. Neither the name NuttX nor the names of its contributors may be
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* used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
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* "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
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* LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
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* FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
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* COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
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* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
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* BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
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* OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
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* AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
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* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
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* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
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* POSSIBILITY OF SUCH DAMAGE.
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*
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****************************************************************************/
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/****************************************************************************
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* Included Files
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****************************************************************************/
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#include <nuttx/config.h>
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#include <sys/types.h>
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#include <assert.h>
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#include <queue.h>
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#include <errno.h>
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#include <nuttx/sched.h>
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#include <nuttx/irq.h>
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#include <nuttx/sched_note.h>
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#include "sched/sched.h"
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#ifndef CONFIG_DISABLE_SIGNALS
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# include "signal/signal.h"
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#endif
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#include "task/task.h"
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: task_terminate
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*
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* Description:
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* This function causes a specified task to cease to exist. Its stack and
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* TCB will be deallocated. This function is the internal implementation
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* of the task_delete() function. It includes and additional parameter
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* to determine if blocking is permitted or not.
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*
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* This function is the final function called all task termination
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* sequences. task_terminate() is called only from task_delete() (with
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* nonblocking == false) and from task_exit() (with nonblocking == true).
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*
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* The path through task_exit() supports the final stops of the exit(),
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* _exit(), and pthread_exit
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*
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* - pthread_exit(). Calls _exit()
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* - exit(). Calls _exit()
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* - _exit(). Calls task_exit() making the currently running task
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* non-running. task_exit then calls task_terminate() (with nonblocking
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* == true) to terminate the non-running task.
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*
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* NOTE: that the state of non-blocking is irrelevant when called through
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* exit() and pthread_exit(). In those cases task_exithook() has already
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* been called with nonblocking == false;
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*
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* Inputs:
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* pid - The task ID of the task to delete. A pid of zero
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* signifies the calling task.
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* nonblocking - True: The task is an unhealthy, partially torn down
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* state and is not permitted to block.
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*
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* Return Value:
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* OK on success; or ERROR on failure
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*
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* This function can fail if the provided pid does not correspond to a
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* task (errno is not set)
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*
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****************************************************************************/
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int task_terminate(pid_t pid, bool nonblocking)
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{
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FAR struct tcb_s *dtcb;
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FAR dq_queue_t *tasklist;
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irqstate_t flags;
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#ifdef CONFIG_SMP
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int cpu;
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#endif
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int ret;
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/* Make sure the task does not become ready-to-run while we are futzing
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* with its TCB. Within the critical section, no new task may be started
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* or terminated (even in the SMP case).
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*/
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flags = enter_critical_section();
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/* Find for the TCB associated with matching PID */
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dtcb = sched_gettcb(pid);
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if (!dtcb)
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{
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/* This PID does not correspond to any known task */
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ret = -ESRCH;
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goto errout_with_lock;
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}
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/* Verify our internal sanity */
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#ifdef CONFIG_SMP
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DEBUGASSERT(dtcb->task_state < NUM_TASK_STATES);
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#else
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DEBUGASSERT(dtcb->task_state != TSTATE_TASK_RUNNING &&
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dtcb->task_state < NUM_TASK_STATES);
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#endif
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/* Remove the task from the OS's task lists. We must be in a critical
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* section and the must must not be running to do this.
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*/
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#ifdef CONFIG_SMP
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/* In the SMP case, the thread may be running on another CPU. If that is
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* the case, then we will pause the CPU that the thread is running on.
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*/
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cpu = sched_cpu_pause(dtcb);
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/* Get the task list associated with the the thread's state and CPU */
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tasklist = TLIST_HEAD(dtcb->task_state, cpu);
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#else
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/* In the non-SMP case, we can be assured that the task to be terminated
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* is not running. get the task list associated with the task state.
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*/
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tasklist = TLIST_HEAD(dtcb->task_state);
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#endif
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/* Remove the task from the task list */
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dq_rem((FAR dq_entry_t *)dtcb, tasklist);
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dtcb->task_state = TSTATE_TASK_INVALID;
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/* At this point, the TCB should no longer be accessible to the system */
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#ifdef CONFIG_SMP
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/* Resume the paused CPU (if any) */
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if (cpu >= 0)
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{
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/* I am not yet sure how to handle a failure here. */
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DEBUGVERIFY(up_cpu_resume(cpu));
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}
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#endif /* CONFIG_SMP */
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leave_critical_section(flags);
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/* Perform common task termination logic (flushing streams, calling
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* functions registered by at_exit/on_exit, etc.). We need to do
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* this as early as possible so that higher level clean-up logic
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* can run in a healthy tasking environment.
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*
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* In the case where the task exits via exit(), task_exithook()
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* may be called twice.
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*
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* I suppose EXIT_SUCCESS is an appropriate return value???
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*/
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task_exithook(dtcb, EXIT_SUCCESS, nonblocking);
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/* Since all tasks pass through this function as the final step in their
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* exit sequence, this is an appropriate place to inform any instrumentation
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* layer that the task no longer exists.
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*/
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sched_note_stop(dtcb);
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/* Deallocate its TCB */
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return sched_releasetcb(dtcb, dtcb->flags & TCB_FLAG_TTYPE_MASK);
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errout_with_lock:
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leave_critical_section(flags);
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return ret;
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}
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