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From: Felix Kuehling <Felix.Kuehling@amd.com>
To: amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Cc: christian.koenig@amd.com
Subject: [PATCH 9/9] drm/amdgpu: Lock the attached dmabuf in unpopulate
Date: Wed, 14 Apr 2021 02:48:04 -0400	[thread overview]
Message-ID: <20210414064804.29356-10-Felix.Kuehling@amd.com> (raw)
In-Reply-To: <20210414064804.29356-1-Felix.Kuehling@amd.com>

amdgpu_ttm_tt_unpopulate can be called during bo_destroy. The dmabuf->resv
must not be held by the caller or dma_buf_detach will deadlock. This is
probably not the right fix. I get a recursive lock warning with the
reservation held in ttm_bo_release. Should unmap_attachment move to
backend_unbind instead?

Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 936b3cfdde55..257750921eed 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1216,9 +1216,22 @@ static void amdgpu_ttm_tt_unpopulate(struct ttm_device *bdev,
 
 	if (ttm->sg && gtt->gobj->import_attach) {
 		struct dma_buf_attachment *attach;
+		bool locked;
 
 		attach = gtt->gobj->import_attach;
+		/* FIXME: unpopulate can be called during bo_destroy.
+		 * The dmabuf->resv must not be held by the caller or
+		 * dma_buf_detach will deadlock. This is probably not
+		 * the right fix. I get a recursive lock warning with the
+		 * reservation held in ttm_bo_releas.. Should
+		 * unmap_attachment move to backend_unbind instead?
+		 */
+		locked = dma_resv_is_locked(attach->dmabuf->resv);
+		if (!locked)
+			dma_resv_lock(attach->dmabuf->resv, NULL);
 		dma_buf_unmap_attachment(attach, ttm->sg, DMA_BIDIRECTIONAL);
+		if (!locked)
+			dma_resv_unlock(attach->dmabuf->resv);
 		ttm->sg = NULL;
 		return;
 	}
-- 
2.31.1

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dri-devel@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/dri-devel

WARNING: multiple messages have this Message-ID (diff)
From: Felix Kuehling <Felix.Kuehling@amd.com>
To: amd-gfx@lists.freedesktop.org, dri-devel@lists.freedesktop.org
Cc: christian.koenig@amd.com
Subject: [PATCH 9/9] drm/amdgpu: Lock the attached dmabuf in unpopulate
Date: Wed, 14 Apr 2021 02:48:04 -0400	[thread overview]
Message-ID: <20210414064804.29356-10-Felix.Kuehling@amd.com> (raw)
In-Reply-To: <20210414064804.29356-1-Felix.Kuehling@amd.com>

amdgpu_ttm_tt_unpopulate can be called during bo_destroy. The dmabuf->resv
must not be held by the caller or dma_buf_detach will deadlock. This is
probably not the right fix. I get a recursive lock warning with the
reservation held in ttm_bo_release. Should unmap_attachment move to
backend_unbind instead?

Signed-off-by: Felix Kuehling <Felix.Kuehling@amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 936b3cfdde55..257750921eed 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1216,9 +1216,22 @@ static void amdgpu_ttm_tt_unpopulate(struct ttm_device *bdev,
 
 	if (ttm->sg && gtt->gobj->import_attach) {
 		struct dma_buf_attachment *attach;
+		bool locked;
 
 		attach = gtt->gobj->import_attach;
+		/* FIXME: unpopulate can be called during bo_destroy.
+		 * The dmabuf->resv must not be held by the caller or
+		 * dma_buf_detach will deadlock. This is probably not
+		 * the right fix. I get a recursive lock warning with the
+		 * reservation held in ttm_bo_releas.. Should
+		 * unmap_attachment move to backend_unbind instead?
+		 */
+		locked = dma_resv_is_locked(attach->dmabuf->resv);
+		if (!locked)
+			dma_resv_lock(attach->dmabuf->resv, NULL);
 		dma_buf_unmap_attachment(attach, ttm->sg, DMA_BIDIRECTIONAL);
+		if (!locked)
+			dma_resv_unlock(attach->dmabuf->resv);
 		ttm->sg = NULL;
 		return;
 	}
-- 
2.31.1

_______________________________________________
amd-gfx mailing list
amd-gfx@lists.freedesktop.org
https://lists.freedesktop.org/mailman/listinfo/amd-gfx

  parent reply	other threads:[~2021-04-14  6:48 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-04-14  6:47 [PATCH 0/9] Implement multi-GPU DMA mappings for KFD Felix Kuehling
2021-04-14  6:47 ` Felix Kuehling
2021-04-14  6:47 ` [PATCH 1/9] drm/amdgpu: Rename kfd_bo_va_list to kfd_mem_attachment Felix Kuehling
2021-04-14  6:47   ` Felix Kuehling
2021-04-14  6:47 ` [PATCH 2/9] drm/amdgpu: Keep a bo-reference per-attachment Felix Kuehling
2021-04-14  6:47   ` Felix Kuehling
2021-04-14  6:47 ` [PATCH 3/9] drm/amdgpu: Simplify AQL queue mapping Felix Kuehling
2021-04-14  6:47   ` Felix Kuehling
2021-04-14  6:47 ` [PATCH 4/9] drm/amdgpu: Add multi-GPU DMA mapping helpers Felix Kuehling
2021-04-14  6:47   ` Felix Kuehling
2021-04-14  6:48 ` [PATCH 5/9] drm/amdgpu: DMA map/unmap when updating GPU mappings Felix Kuehling
2021-04-14  6:48   ` Felix Kuehling
2021-04-14  6:48 ` [PATCH 6/9] drm/amdgpu: Move kfd_mem_attach outside reservation Felix Kuehling
2021-04-14  6:48   ` Felix Kuehling
2021-04-14  6:48 ` [PATCH 7/9] drm/amdgpu: Add DMA mapping of GTT BOs Felix Kuehling
2021-04-14  6:48   ` Felix Kuehling
2021-04-14  6:48 ` [PATCH 8/9] drm/ttm: Don't count pages in SG BOs against pages_limit Felix Kuehling
2021-04-14  6:48   ` Felix Kuehling
2021-04-14  6:51   ` Christian König
2021-04-14  6:51     ` Christian König
2021-04-14  9:15     ` Daniel Vetter
2021-04-14  9:15       ` Daniel Vetter
2021-04-14  9:19       ` Christian König
2021-04-14  9:19         ` Christian König
2021-04-14 10:26         ` Daniel Vetter
2021-04-14 10:26           ` Daniel Vetter
2021-04-14 10:49           ` Christian König
2021-04-14 10:49             ` Christian König
2021-04-14 12:25             ` Daniel Vetter
2021-04-14 12:25               ` Daniel Vetter
2021-04-14 12:43               ` Christian König
2021-04-14 12:43                 ` Christian König
2021-04-14 12:47                 ` Daniel Vetter
2021-04-14 12:47                   ` Daniel Vetter
2021-04-14 12:49                   ` Christian König
2021-04-14 12:49                     ` Christian König
2021-04-14 14:41               ` Felix Kuehling
2021-04-14 14:41                 ` Felix Kuehling
2021-04-14  6:48 ` Felix Kuehling [this message]
2021-04-14  6:48   ` [PATCH 9/9] drm/amdgpu: Lock the attached dmabuf in unpopulate Felix Kuehling
  -- strict thread matches above, loose matches on Subject: below --
2021-04-14  6:46 [PATCH 0/9] Implement multi-GPU DMA mappings for KFD Felix Kuehling
2021-04-14  6:46 ` [PATCH 9/9] drm/amdgpu: Lock the attached dmabuf in unpopulate Felix Kuehling
2021-04-14  7:33   ` Christian König
2021-04-14 15:15     ` Felix Kuehling
2021-04-14 15:15       ` Felix Kuehling
2021-04-15  7:41       ` Christian König
2021-04-15  7:41         ` Christian König
2021-04-15 14:29         ` Felix Kuehling
2021-04-15 14:29           ` Felix Kuehling

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