0dedbcd4ae
This moves task / thread cancel point logic from the NuttX kernel into libc, while the data needed by the cancel point logic is moved to TLS. The change is an enabler to move user-space APIs to libc as well, for a coherent user/kernel separation.
485 lines
14 KiB
C
485 lines
14 KiB
C
/****************************************************************************
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* sched/task/task_exithook.c
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*
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* Licensed to the Apache Software Foundation (ASF) under one or more
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* contributor license agreements. See the NOTICE file distributed with
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* this work for additional information regarding copyright ownership. The
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* ASF licenses this file to you under the Apache License, Version 2.0 (the
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* "License"); you may not use this file except in compliance with the
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* License. You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
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* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
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* License for the specific language governing permissions and limitations
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* under the License.
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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 <stdlib.h>
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#include <unistd.h>
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#include <signal.h>
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#include <assert.h>
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#include <debug.h>
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#include <errno.h>
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#include <nuttx/sched.h>
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#include <nuttx/fs/fs.h>
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#include <nuttx/mm/mm.h>
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#include "sched/sched.h"
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#include "group/group.h"
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#include "signal/signal.h"
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#include "task/task.h"
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/****************************************************************************
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* Private Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxtask_exitstatus
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*
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* Description:
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* Report exit status when main task of a task group exits
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*
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****************************************************************************/
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#ifdef CONFIG_SCHED_CHILD_STATUS
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static inline void nxtask_exitstatus(FAR struct task_group_s *group,
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int status)
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{
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FAR struct child_status_s *child;
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/* Check if the parent task group has suppressed retention of
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* child exit status information.
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*/
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if ((group->tg_flags & GROUP_FLAG_NOCLDWAIT) == 0)
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{
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/* No.. Find the exit status entry for this task in the parent TCB */
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child = group_find_child(group, nxsched_getpid());
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if (child)
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{
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/* Save the exit status.. For the case of HAVE_GROUP_MEMBERS,
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* the child status will be as exited until the last member
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* of the task group exits.
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*/
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child->ch_status = status;
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}
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}
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group->tg_exitcode = status;
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}
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#else
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# define nxtask_exitstatus(group,status) (group)->tg_exitcode = (status);
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#endif /* CONFIG_SCHED_CHILD_STATUS */
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/****************************************************************************
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* Name: nxtask_groupexit
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*
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* Description:
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* Mark that the final thread of a child task group as exited.
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*
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****************************************************************************/
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#ifdef CONFIG_SCHED_CHILD_STATUS
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static inline void nxtask_groupexit(FAR struct task_group_s *group)
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{
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FAR struct child_status_s *child;
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/* Check if the parent task group has suppressed retention of child exit
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* status information.
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*/
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if ((group->tg_flags & GROUP_FLAG_NOCLDWAIT) == 0)
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{
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/* No.. Find the exit status entry for this task in the parent TCB */
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child = group_find_child(group, nxsched_getpid());
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if (child)
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{
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/* Mark that all members of the child task group has exited */
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child->ch_flags |= CHILD_FLAG_EXITED;
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}
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}
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}
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#else
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# define nxtask_groupexit(group)
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#endif /* CONFIG_SCHED_CHILD_STATUS */
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/****************************************************************************
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* Name: nxtask_sigchild
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*
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* Description:
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* Send the SIGCHLD signal to the parent thread
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*
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****************************************************************************/
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#ifdef CONFIG_SCHED_HAVE_PARENT
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#ifdef HAVE_GROUP_MEMBERS
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static inline void nxtask_sigchild(pid_t ppid, FAR struct tcb_s *ctcb,
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int status)
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{
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FAR struct task_group_s *chgrp = ctcb->group;
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FAR struct task_group_s *pgrp;
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siginfo_t info;
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DEBUGASSERT(chgrp);
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/* Get the parent task group. It is possible that all of the members of
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* the parent task group have exited. This would not be an error. In
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* this case, the child task group has been orphaned.
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*/
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pgrp = group_findbypid(ppid);
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if (!pgrp)
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{
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/* Set the task group ID to an invalid group ID. The dead parent
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* task group ID could get reused some time in the future.
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*/
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chgrp->tg_ppid = INVALID_PROCESS_ID;
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return;
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}
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/* Save the exit status now if this is the main thread of the task group
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* that is exiting. Only the exiting main task of a task group carries
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* interpretable exit Check if this is the main task that is exiting.
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*/
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#ifndef CONFIG_DISABLE_PTHREAD
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if ((ctcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_PTHREAD)
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#endif
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{
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nxtask_exitstatus(pgrp, status);
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}
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/* But only the final exiting thread in a task group, whatever it is,
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* should generate SIGCHLD.
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*/
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if (chgrp->tg_nmembers == 1)
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{
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/* Mark that all of the threads in the task group have exited */
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nxtask_groupexit(pgrp);
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/* Create the siginfo structure. We don't actually know the cause.
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* That is a bug. Let's just say that the child task just exited
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* for now.
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*/
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info.si_signo = SIGCHLD;
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info.si_code = CLD_EXITED;
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info.si_errno = OK;
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info.si_value.sival_ptr = NULL;
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info.si_pid = chgrp->tg_pid;
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info.si_status = pgrp->tg_exitcode;
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/* Send the signal to one thread in the group */
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group_signal(pgrp, &info);
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}
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}
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#else /* HAVE_GROUP_MEMBERS */
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static inline void nxtask_sigchild(FAR struct tcb_s *ptcb,
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FAR struct tcb_s *ctcb, int status)
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{
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siginfo_t info;
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/* If task groups are not supported then we will report SIGCHLD when the
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* task exits. Unfortunately, there could still be threads in the group
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* that are still running.
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*/
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#ifndef CONFIG_DISABLE_PTHREAD
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if ((ctcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_PTHREAD)
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#endif
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{
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#ifdef CONFIG_SCHED_CHILD_STATUS
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/* Save the exit status now of the main thread */
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nxtask_exitstatus(ptcb->group, status);
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#else /* CONFIG_SCHED_CHILD_STATUS */
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/* Exit status is not retained. Just decrement the number of
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* children from this parent.
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*/
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DEBUGASSERT(ptcb->group != NULL && ptcb->group->tg_nchildren > 0);
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ptcb->group->tg_nchildren--;
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#endif /* CONFIG_SCHED_CHILD_STATUS */
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/* Create the siginfo structure. We don't actually know the cause.
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* That is a bug. Let's just say that the child task just exited
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* for now.
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*/
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info.si_signo = SIGCHLD;
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info.si_code = CLD_EXITED;
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info.si_errno = OK;
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info.si_value.sival_ptr = NULL;
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info.si_pid = ctcb->group->tg_pid;
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info.si_status = status;
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/* Send the signal. We need to use this internal interface so that we
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* can provide the correct si_code value with the signal.
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*/
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nxsig_tcbdispatch(ptcb, &info);
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}
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}
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#endif /* HAVE_GROUP_MEMBERS */
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#else /* CONFIG_SCHED_HAVE_PARENT */
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# define nxtask_sigchild(x,ctcb,status)
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#endif /* CONFIG_SCHED_HAVE_PARENT */
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/****************************************************************************
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* Name: nxtask_signalparent
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*
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* Description:
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* Send the SIGCHLD signal to the parent task group
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*
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****************************************************************************/
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#ifdef CONFIG_SCHED_HAVE_PARENT
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static inline void nxtask_signalparent(FAR struct tcb_s *ctcb, int status)
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{
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#ifdef HAVE_GROUP_MEMBERS
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DEBUGASSERT(ctcb && ctcb->group);
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/* Keep things stationary throughout the following */
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sched_lock();
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/* Send SIGCHLD to all members of the parent's task group */
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nxtask_sigchild(ctcb->group->tg_ppid, ctcb, status);
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sched_unlock();
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#else
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FAR struct tcb_s *ptcb;
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/* Keep things stationary throughout the following */
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sched_lock();
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/* Get the TCB of the receiving, parent task. We do this early to
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* handle multiple calls to nxtask_signalparent.
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*/
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ptcb = nxsched_get_tcb(ctcb->group->tg_ppid);
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if (ptcb == NULL)
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{
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/* The parent no longer exists... bail */
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sched_unlock();
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return;
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}
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/* Send SIGCHLD to all members of the parent's task group. NOTE that the
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* SIGCHLD signal is only sent once either (1) if this is the final thread
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* of the task group that is exiting (HAVE_GROUP_MEMBERS) or (2) if the
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* main thread of the group is exiting (!HAVE_GROUP_MEMBERS).
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*/
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nxtask_sigchild(ptcb, ctcb, status);
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sched_unlock();
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#endif
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}
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#else
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# define nxtask_signalparent(ctcb,status)
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#endif
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/****************************************************************************
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* Name: nxtask_exitwakeup
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*
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* Description:
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* Wakeup any tasks waiting for this task to exit
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*
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****************************************************************************/
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#if defined(CONFIG_SCHED_WAITPID) && !defined(CONFIG_SCHED_HAVE_PARENT)
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static inline void nxtask_exitwakeup(FAR struct tcb_s *tcb, int status)
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{
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FAR struct task_group_s *group = tcb->group;
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/* Have we already left the group? */
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if (group)
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{
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/* Only tasks (and kernel threads) return valid status. Record the
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* exit status when the task exists. The group, however, may still
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* be executing.
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*/
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#ifndef CONFIG_DISABLE_PTHREAD
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if ((tcb->flags & TCB_FLAG_TTYPE_MASK) != TCB_FLAG_TTYPE_PTHREAD)
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#endif
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{
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/* Report the exit status. We do not nullify tg_statloc here
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* because we want to prevent other tasks from registering for
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* the return status. There is only one task per task group,
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* there for, this logic should execute exactly once in the
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* lifetime of the task group.
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*
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* "If more than one thread is suspended in waitpid() awaiting
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* termination of the same process, exactly one thread will
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* return the process status at the time of the target process
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* termination."
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*
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* Hmmm.. what do we return to the others?
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*/
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if (group->tg_statloc != NULL)
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{
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*group->tg_statloc = status << 8;
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}
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}
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/* Is this the last thread in the group? */
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if (group->tg_nmembers == 1)
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{
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/* Yes.. Wakeup any tasks waiting for this task to exit */
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group->tg_statloc = NULL;
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group->tg_waitflags = 0;
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while (group->tg_exitsem.semcount < 0)
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{
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/* Wake up the thread */
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nxsem_post(&group->tg_exitsem);
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}
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}
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}
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}
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#else
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# define nxtask_exitwakeup(tcb, status)
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#endif
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/****************************************************************************
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* Public Functions
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****************************************************************************/
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/****************************************************************************
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* Name: nxtask_exithook
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*
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* Description:
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* This function implements some of the internal logic of exit() and
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* task_delete(). This function performs some clean-up and other actions
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* required when a task exits:
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*
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* - All open streams are flushed and closed.
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* - All functions registered with atexit() and on_exit() are called, in
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* the reverse order of their registration.
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*
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* When called from exit(), the tcb still resides at the head of the ready-
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* to-run list. The following logic is safe because we will not be
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* returning from the exit() call.
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*
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* When called from nxtask_terminate() we are operating on a different
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* thread; on the thread that called task_delete(). In this case,
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* task_delete will have already removed the tcb from the ready-to-run
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* list to prevent any further action on this task.
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*
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****************************************************************************/
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void nxtask_exithook(FAR struct tcb_s *tcb, int status)
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{
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#ifdef CONFIG_SCHED_DUMP_LEAK
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struct mm_memdump_s dump =
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{
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tcb->pid,
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# if CONFIG_MM_BACKTRACE >= 0
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0,
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ULONG_MAX
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# endif
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};
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#endif
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/* Under certain conditions, nxtask_exithook() can be called multiple
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* times. A bit in the TCB was set the first time this function was
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* called. If that bit is set, then just exit doing nothing more..
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*/
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if ((tcb->flags & TCB_FLAG_EXIT_PROCESSING) != 0)
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{
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return;
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}
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/* If the task was terminated by another task, it may be in an unknown
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* state. Make some feeble effort to recover the state.
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*/
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nxtask_recover(tcb);
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/* NOTE: signal handling needs to be done in a criticl section */
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#ifdef CONFIG_SMP
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irqstate_t flags = enter_critical_section();
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#endif
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/* Send the SIGCHLD signal to the parent task group */
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nxtask_signalparent(tcb, status);
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/* Wakeup any tasks waiting for this task to exit */
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nxtask_exitwakeup(tcb, status);
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/* Leave the task group. Perhaps discarding any un-reaped child
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* status (no zombies here!)
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*/
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group_leave(tcb);
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/* Deallocate anything left in the TCB's queues */
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nxsig_cleanup(tcb); /* Deallocate Signal lists */
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#ifdef CONFIG_SCHED_DUMP_LEAK
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if ((tcb->flags & TCB_FLAG_TTYPE_MASK) == TCB_FLAG_TTYPE_KERNEL)
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{
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kmm_memdump(&dump);
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}
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else
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{
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umm_memdump(&dump);
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}
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#endif
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/* This function can be re-entered in certain cases. Set a flag
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* bit in the TCB to not that we have already completed this exit
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* processing.
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*/
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tcb->flags |= TCB_FLAG_EXIT_PROCESSING;
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#ifdef CONFIG_SMP
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leave_critical_section(flags);
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#endif
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}
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