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drm/amdkfd: fix some race conditions in vram buffer alloc/free of svm code

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[ Upstream commit 7bfaa160caed8192f8262c4638f552cad94bcf5a ]

This patch fixes:
1: ref number of prange's svm_bo got decreased by an async call from hmm. When
wait svm_bo of prange got released we shoul also wait prang->svm_bo become NULL,
otherwise prange->svm_bo may be set to null after allocate new vram buffer.

2: During waiting svm_bo of prange got released in a while loop should reschedule
current task to give other tasks oppotunity to run, specially the the workque
task that handles svm_bo ref release, otherwise we may enter to softlock.

Signed-off-by: Xiaogang.Chen <xiaogang.chen@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Xiaogang Chen 2023-09-20 11:02:51 -05:00 committed by Greg Kroah-Hartman
parent 03b98d789a
commit da27d73ec9
1 changed files with 4 additions and 4 deletions
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8
drivers/gpu/drm/amd/amdkfd/kfd_svm.c
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@ -495,11 +495,11 @@ svm_range_validate_svm_bo(struct kfd_node *node, struct svm_range *prange)
/* We need a new svm_bo. Spin-loop to wait for concurrent
* svm_range_bo_release to finish removing this range from
* its range list. After this, it is safe to reuse the
* svm_bo pointer and svm_bo_list head.
* its range list and set prange->svm_bo to null. After this,
* it is safe to reuse the svm_bo pointer and svm_bo_list head.
*/
while (!list_empty_careful(&prange->svm_bo_list))
;
while (!list_empty_careful(&prange->svm_bo_list) || prange->svm_bo)
cond_resched();
return false;
}