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authorAndrzej Hajda <andrzej.hajda@intel.com>2023-08-21 17:30:35 +0200
committerRodrigo Vivi <rodrigo.vivi@intel.com>2023-08-30 17:32:48 +0200
commit5eefc5307c983b59344a4cb89009819f580c84fa (patch)
tree04a173a41f8db2f89166a7edd63187083149092c
parentMerge tag 'drm-intel-next-fixes-2023-08-24' of git://anongit.freedesktop.org/... (diff)
downloadlinux-5eefc5307c983b59344a4cb89009819f580c84fa.tar.xz
linux-5eefc5307c983b59344a4cb89009819f580c84fa.zip
drm/i915: mark requests for GuC virtual engines to avoid use-after-free
References to i915_requests may be trapped by userspace inside a sync_file or dmabuf (dma-resv) and held indefinitely across different proceses. To counter-act the memory leaks, we try to not to keep references from the request past their completion. On the other side on fence release we need to know if rq->engine is valid and points to hw engine (true for non-virtual requests). To make it possible extra bit has been added to rq->execution_mask, for marking virtual engines. Fixes: bcb9aa45d5a0 ("Revert "drm/i915: Hold reference to intel_context over life of i915_request"") Signed-off-by: Chris Wilson <chris.p.wilson@linux.intel.com> Signed-off-by: Andrzej Hajda <andrzej.hajda@intel.com> Reviewed-by: Andi Shyti <andi.shyti@linux.intel.com> Signed-off-by: Andi Shyti <andi.shyti@linux.intel.com> Link: https://patchwork.freedesktop.org/patch/msgid/20230821153035.3903006-1-andrzej.hajda@intel.com (cherry picked from commit 280410677af763f3871b93e794a199cfcf6fb580) Signed-off-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
-rw-r--r--drivers/gpu/drm/i915/gt/intel_engine_types.h1
-rw-r--r--drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c3
-rw-r--r--drivers/gpu/drm/i915/i915_request.c7
3 files changed, 6 insertions, 5 deletions
diff --git a/drivers/gpu/drm/i915/gt/intel_engine_types.h b/drivers/gpu/drm/i915/gt/intel_engine_types.h
index e99a6fa03d45..a7e677598004 100644
--- a/drivers/gpu/drm/i915/gt/intel_engine_types.h
+++ b/drivers/gpu/drm/i915/gt/intel_engine_types.h
@@ -58,6 +58,7 @@ struct i915_perf_group;
typedef u32 intel_engine_mask_t;
#define ALL_ENGINES ((intel_engine_mask_t)~0ul)
+#define VIRTUAL_ENGINES BIT(BITS_PER_TYPE(intel_engine_mask_t) - 1)
struct intel_hw_status_page {
struct list_head timelines;
diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
index a0e3ef1c65d2..b5b7f2fe8c78 100644
--- a/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
+++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_submission.c
@@ -5470,6 +5470,9 @@ guc_create_virtual(struct intel_engine_cs **siblings, unsigned int count,
ve->base.flags = I915_ENGINE_IS_VIRTUAL;
+ BUILD_BUG_ON(ilog2(VIRTUAL_ENGINES) < I915_NUM_ENGINES);
+ ve->base.mask = VIRTUAL_ENGINES;
+
intel_context_init(&ve->context, &ve->base);
for (n = 0; n < count; n++) {
diff --git a/drivers/gpu/drm/i915/i915_request.c b/drivers/gpu/drm/i915/i915_request.c
index 7c7da284990d..f59081066a19 100644
--- a/drivers/gpu/drm/i915/i915_request.c
+++ b/drivers/gpu/drm/i915/i915_request.c
@@ -134,9 +134,7 @@ static void i915_fence_release(struct dma_fence *fence)
i915_sw_fence_fini(&rq->semaphore);
/*
- * Keep one request on each engine for reserved use under mempressure
- * do not use with virtual engines as this really is only needed for
- * kernel contexts.
+ * Keep one request on each engine for reserved use under mempressure.
*
* We do not hold a reference to the engine here and so have to be
* very careful in what rq->engine we poke. The virtual engine is
@@ -166,8 +164,7 @@ static void i915_fence_release(struct dma_fence *fence)
* know that if the rq->execution_mask is a single bit, rq->engine
* can be a physical engine with the exact corresponding mask.
*/
- if (!intel_engine_is_virtual(rq->engine) &&
- is_power_of_2(rq->execution_mask) &&
+ if (is_power_of_2(rq->execution_mask) &&
!cmpxchg(&rq->engine->request_pool, NULL, rq))
return;