linux_dsm_epyc7002/drivers/gpu/drm/amd/amdgpu/amdgpu_sched.c
Christian König e284022163 drm/amdgpu: fix incorrect mutex usage v3
Before this patch the scheduler fence was created when we push the job
into the queue, so we could only get the fence after pushing it.

The mutex now was necessary to prevent the thread pushing the jobs to
the hardware from running faster than the thread pushing the jobs into
the queue.

Otherwise the thread pushing jobs into the queue would have accessed
possible freed up memory when it tries to get a reference to the fence.

So what you get in the end is thread A:
mutex_lock(&job->lock);
...
Kick of thread B.
...
mutex_unlock(&job->lock);

And thread B:
mutex_lock(&job->lock);
....
mutex_unlock(&job->lock);
kfree(job);

I'm actually not sure if I'm still up to date on this, but this usage
pattern used to be not allowed with mutexes. See here as well
https://lwn.net/Articles/575460/.

v2: remove unrelated changes, fix missing owner
v3: rebased, add more commit message

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Alex Deucher <alexander.deucher@amd.com>
2015-11-16 11:05:58 -05:00

109 lines
3.1 KiB
C

/*
* Copyright 2015 Advanced Micro Devices, Inc.
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in
* all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
* OTHER DEALINGS IN THE SOFTWARE.
*
*
*/
#include <linux/kthread.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <drm/drmP.h>
#include "amdgpu.h"
#include "amdgpu_trace.h"
static struct fence *amdgpu_sched_dependency(struct amd_sched_job *sched_job)
{
struct amdgpu_job *job = to_amdgpu_job(sched_job);
return amdgpu_sync_get_fence(&job->ibs->sync);
}
static struct fence *amdgpu_sched_run_job(struct amd_sched_job *sched_job)
{
struct amdgpu_fence *fence = NULL;
struct amdgpu_job *job;
int r;
if (!sched_job) {
DRM_ERROR("job is null\n");
return NULL;
}
job = to_amdgpu_job(sched_job);
trace_amdgpu_sched_run_job(job);
r = amdgpu_ib_schedule(job->adev, job->num_ibs, job->ibs, job->owner);
if (r) {
DRM_ERROR("Error scheduling IBs (%d)\n", r);
goto err;
}
fence = job->ibs[job->num_ibs - 1].fence;
fence_get(&fence->base);
err:
if (job->free_job)
job->free_job(job);
kfree(job);
return fence ? &fence->base : NULL;
}
struct amd_sched_backend_ops amdgpu_sched_ops = {
.dependency = amdgpu_sched_dependency,
.run_job = amdgpu_sched_run_job,
};
int amdgpu_sched_ib_submit_kernel_helper(struct amdgpu_device *adev,
struct amdgpu_ring *ring,
struct amdgpu_ib *ibs,
unsigned num_ibs,
int (*free_job)(struct amdgpu_job *),
void *owner,
struct fence **f)
{
int r = 0;
if (amdgpu_enable_scheduler) {
struct amdgpu_job *job =
kzalloc(sizeof(struct amdgpu_job), GFP_KERNEL);
if (!job)
return -ENOMEM;
job->base.sched = &ring->sched;
job->base.s_entity = &adev->kernel_ctx.rings[ring->idx].entity;
job->base.s_fence = amd_sched_fence_create(job->base.s_entity, owner);
if (!job->base.s_fence) {
kfree(job);
return -ENOMEM;
}
*f = fence_get(&job->base.s_fence->base);
job->adev = adev;
job->ibs = ibs;
job->num_ibs = num_ibs;
job->owner = owner;
job->free_job = free_job;
amd_sched_entity_push_job(&job->base);
} else {
r = amdgpu_ib_schedule(adev, num_ibs, ibs, owner);
if (r)
return r;
*f = fence_get(&ibs[num_ibs - 1].fence->base);
}
return 0;
}