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From 5c79e8d34f987f4fdddd6e152845f18d4aecbfde Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Nicolai=20H=C3=A4hnle?= <nicolai.haehnle@amd.com>
Date: Thu, 28 Sep 2017 11:57:32 +0200
Subject: [PATCH 1961/4131] drm/amd/sched: fix deadlock caused by unsignaled
fences of deleted jobs
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Highly concurrent Piglit runs can trigger a race condition where a pending
SDMA job on a buffer object is never executed because the corresponding
process is killed (perhaps due to a crash). Since the job's fences were
never signaled, the buffer object was effectively leaked. Worse, the
buffer was stuck wherever it happened to be at the time, possibly in VRAM.
The symptom was user space processes stuck in interruptible waits with
kernel stacks like:
[<ffffffffbc5e6722>] dma_fence_default_wait+0x112/0x250
[<ffffffffbc5e6399>] dma_fence_wait_timeout+0x39/0xf0
[<ffffffffbc5e82d2>] reservation_object_wait_timeout_rcu+0x1c2/0x300
[<ffffffffc03ce56f>] ttm_bo_cleanup_refs_and_unlock+0xff/0x1a0 [ttm]
[<ffffffffc03cf1ea>] ttm_mem_evict_first+0xba/0x1a0 [ttm]
[<ffffffffc03cf611>] ttm_bo_mem_space+0x341/0x4c0 [ttm]
[<ffffffffc03cfc54>] ttm_bo_validate+0xd4/0x150 [ttm]
[<ffffffffc03cffbd>] ttm_bo_init_reserved+0x2ed/0x420 [ttm]
[<ffffffffc042f523>] amdgpu_bo_create_restricted+0x1f3/0x470 [amdgpu]
[<ffffffffc042f9fa>] amdgpu_bo_create+0xda/0x220 [amdgpu]
[<ffffffffc04349ea>] amdgpu_gem_object_create+0xaa/0x140 [amdgpu]
[<ffffffffc0434f97>] amdgpu_gem_create_ioctl+0x97/0x120 [amdgpu]
[<ffffffffc037ddba>] drm_ioctl+0x1fa/0x480 [drm]
[<ffffffffc041904f>] amdgpu_drm_ioctl+0x4f/0x90 [amdgpu]
[<ffffffffbc23db33>] do_vfs_ioctl+0xa3/0x5f0
[<ffffffffbc23e0f9>] SyS_ioctl+0x79/0x90
[<ffffffffbc864ffb>] entry_SYSCALL_64_fastpath+0x1e/0xad
[<ffffffffffffffff>] 0xffffffffffffffff
Note: The correctness of this change depends on the earlier commit
"drm/amd/sched: move adding finish callback to amd_sched_job_begin"
v2: set an error on the finished fence
Signed-off-by: Nicolai Hähnle <nicolai.haehnle@amd.com>
Reviewed-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Andres Rodriguez <andresx7@gmail.com>
Conflicts:
drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
Change-Id: I5c0955c44a83db23bd74282e1ae6e0bfd6e71b93
---
drivers/gpu/drm/amd/scheduler/gpu_scheduler.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
index 4693be2..37e8b8d 100644
--- a/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
+++ b/drivers/gpu/drm/amd/scheduler/gpu_scheduler.c
@@ -227,9 +227,15 @@ void amd_sched_entity_fini(struct amd_gpu_scheduler *sched,
*/
kthread_park(sched->thread);
kthread_unpark(sched->thread);
- while (kfifo_out(&entity->job_queue, &job, sizeof(job)))
+ while (kfifo_out(&entity->job_queue, &job, sizeof(job))) {
+ struct amd_sched_fence *s_fence = job->s_fence;
+ amd_sched_fence_scheduled(s_fence);
+ dma_fence_set_error(&s_fence->finished, -ESRCH);
+ amd_sched_fence_finished(s_fence);
+ dma_fence_put(&s_fence->finished);
sched->ops->free_job(job);
-
+ }
+
}
kfifo_free(&entity->job_queue);
}
--
2.7.4
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