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c58029ad24
The pmu init thread typically returns immediately without calling nvgpu_thread_should_stop(). pmu_pg_kill_task() checks if the thread is running, and if it is, calls nvgpu_thread_stop(). However, there's a race condition where the init thread could have exited between the time that kill_task() checked the running flag and the time we actually stop the thread, leading to a kernel crash. Fix this by making the running flag in the nvgpu_thread struct atomic. Both the thread proxy function and the thread_stop() function will set the flag to false. In the case of nvgpu_thread_proxy(), if the flag is already false, then nvgpu_thread_stop() has already reset it, at which point we just wait for nvgpu_thread_should_stop() to return true. In the case of nvgpu_thread_stop(), if the flag is already false, then the thread proxy function has already exited, and there is nothing more to do. Bug 2591298 Change-Id: I9ba6b63c30a5c3e1df11e790094836b44373122b Signed-off-by: Peter Daifuku <pdaifuku@nvidia.com> Reviewed-on: https://git-master.nvidia.com/r/2230358 GVS: Gerrit_Virtual_Submit Reviewed-by: Thomas Fleury <tfleury@nvidia.com> Reviewed-by: Alex Waterman <alexw@nvidia.com> Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com> Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
101 lines
2.5 KiB
C
101 lines
2.5 KiB
C
/*
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* Copyright (c) 2017-2019, NVIDIA CORPORATION. All rights reserved.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program. If not, see <http://www.gnu.org/licenses/>.
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*/
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#include <linux/kthread.h>
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#include <nvgpu/thread.h>
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#include <nvgpu/timers.h>
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int nvgpu_thread_proxy(void *threaddata)
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{
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struct nvgpu_thread *thread = threaddata;
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int ret = thread->fn(thread->data);
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bool was_running;
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was_running = nvgpu_atomic_xchg(&thread->running, false);
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/* if the thread was not running, then nvgpu_thread_stop() was
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* called, so just wait until we get the notification that we should
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* stop.
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*/
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if (!was_running) {
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while (!nvgpu_thread_should_stop(thread)) {
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nvgpu_usleep_range(5000, 5100);
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}
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}
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return ret;
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}
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int nvgpu_thread_create(struct nvgpu_thread *thread,
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void *data,
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int (*threadfn)(void *data), const char *name)
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{
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struct task_struct *task = kthread_create(nvgpu_thread_proxy,
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thread, name);
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if (IS_ERR(task))
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return PTR_ERR(task);
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thread->task = task;
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thread->fn = threadfn;
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thread->data = data;
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nvgpu_atomic_set(&thread->running, true);
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wake_up_process(task);
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return 0;
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};
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void nvgpu_thread_stop(struct nvgpu_thread *thread)
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{
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bool was_running;
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if (thread->task) {
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was_running = nvgpu_atomic_xchg(&thread->running, false);
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if (was_running) {
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kthread_stop(thread->task);
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}
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thread->task = NULL;
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}
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};
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void nvgpu_thread_stop_graceful(struct nvgpu_thread *thread,
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void (*thread_stop_fn)(void *data), void *data)
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{
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/*
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* Threads waiting on wq's should have nvgpu_thread_should_stop()
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* as one of its wakeup condition. This allows the thread to be woken
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* up when kthread_stop() is invoked and does not require an additional
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* callback to wakeup the sleeping thread.
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*/
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nvgpu_thread_stop(thread);
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};
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bool nvgpu_thread_should_stop(struct nvgpu_thread *thread)
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{
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return kthread_should_stop();
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};
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bool nvgpu_thread_is_running(struct nvgpu_thread *thread)
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{
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return nvgpu_atomic_read(&thread->running);
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};
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void nvgpu_thread_join(struct nvgpu_thread *thread)
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{
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while (nvgpu_atomic_read(&thread->running)) {
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nvgpu_msleep(10);
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}
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};
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