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* [Intel-gfx] [PATCH] drm/i915/selftests: Push the fake iommu device from the stack to data
@ 2020-08-18 18:43 Chris Wilson
  2020-08-18 19:10 ` Matthew Auld
                   ` (2 more replies)
  0 siblings, 3 replies; 4+ messages in thread
From: Chris Wilson @ 2020-08-18 18:43 UTC (permalink / raw)
  To: intel-gfx; +Cc: Chris Wilson

Since we store a pointer to the fake iommu device that is allocated on
the stack, as soon as we leave the function it goes out of scope and any
future dereference is undefined behaviour. Just in case we may need to
look at the fake iommu device after initialiation, move the allocation
from the stack into the data.

Fixes: 01b9d4e21148 ("iommu/vt-d: Use dev_iommu_priv_get/set()")
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
---
 drivers/gpu/drm/i915/selftests/mock_gem_device.c | 12 +++++-------
 1 file changed, 5 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/i915/selftests/mock_gem_device.c b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
index f127e633f7ca..397c313a8b69 100644
--- a/drivers/gpu/drm/i915/selftests/mock_gem_device.c
+++ b/drivers/gpu/drm/i915/selftests/mock_gem_device.c
@@ -118,11 +118,11 @@ static struct dev_pm_domain pm_domain = {
 
 struct drm_i915_private *mock_gem_device(void)
 {
-	struct drm_i915_private *i915;
-	struct pci_dev *pdev;
 #if IS_ENABLED(CONFIG_IOMMU_API) && defined(CONFIG_INTEL_IOMMU)
-	struct dev_iommu iommu;
+	static struct dev_iommu fake_iommu = { .priv = (void *)-1 };
 #endif
+	struct drm_i915_private *i915;
+	struct pci_dev *pdev;
 	int err;
 
 	pdev = kzalloc(sizeof(*pdev), GFP_KERNEL);
@@ -141,10 +141,8 @@ struct drm_i915_private *mock_gem_device(void)
 	dma_coerce_mask_and_coherent(&pdev->dev, DMA_BIT_MASK(64));
 
 #if IS_ENABLED(CONFIG_IOMMU_API) && defined(CONFIG_INTEL_IOMMU)
-	/* HACK HACK HACK to disable iommu for the fake device; force identity mapping */
-	memset(&iommu, 0, sizeof(iommu));
-	iommu.priv = (void *)-1;
-	pdev->dev.iommu = &iommu;
+	/* HACK to disable iommu for the fake device; force identity mapping */
+	pdev->dev.iommu = &fake_iommu;
 #endif
 
 	pci_set_drvdata(pdev, i915);
-- 
2.20.1

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^ permalink raw reply related	[flat|nested] 4+ messages in thread
end of thread, other threads:[~2020-08-18 21:51 UTC | newest]

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-08-18 18:43 [Intel-gfx] [PATCH] drm/i915/selftests: Push the fake iommu device from the stack to data Chris Wilson
2020-08-18 19:10 ` Matthew Auld
2020-08-18 19:29 ` [Intel-gfx] ✓ Fi.CI.BAT: success for " Patchwork
2020-08-18 21:51 ` [Intel-gfx] ✗ Fi.CI.IGT: failure " Patchwork

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