[PATCH] drm/amdgpu: Fix potential integer overflow in scheduler mask calculations

Karol Przybylski karprzy7 at gmail.com
Sun Dec 15 12:28:57 UTC 2024


The use of 1 << i in scheduler mask calculations can result in an
unintentional integer overflow due to the expression being
evaluated as a 32-bit signed integer.

This patch replaces 1 << i with 1ULL << i to ensure the operation
is performed as a 64-bit unsigned integer, preventing overflow

Discovered in coverity scan, CID 1636393, 1636175, 1636007, 1635853

Fixes: c5c63d9cb5d3b drm/amdgpu: add amdgpu_gfx_sched_mask and amdgpu_compute_sched_mask debugfs
Signed-off-by: Karol Przybylski <karprzy7 at gmail.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
index 69a6b6dba0a5..8fb6c5f6a060 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_gfx.c
@@ -2050,7 +2050,7 @@ static int amdgpu_debugfs_gfx_sched_mask_set(void *data, u64 val)
 	if (!adev)
 		return -ENODEV;
 
-	mask = (1 << adev->gfx.num_gfx_rings) - 1;
+	mask = (1ULL << adev->gfx.num_gfx_rings) - 1;
 	if ((val & mask) == 0)
 		return -EINVAL;
 
@@ -2078,7 +2078,7 @@ static int amdgpu_debugfs_gfx_sched_mask_get(void *data, u64 *val)
 	for (i = 0; i < adev->gfx.num_gfx_rings; ++i) {
 		ring = &adev->gfx.gfx_ring[i];
 		if (ring->sched.ready)
-			mask |= 1 << i;
+			mask |= 1ULL << i;
 	}
 
 	*val = mask;
@@ -2120,7 +2120,7 @@ static int amdgpu_debugfs_compute_sched_mask_set(void *data, u64 val)
 	if (!adev)
 		return -ENODEV;
 
-	mask = (1 << adev->gfx.num_compute_rings) - 1;
+	mask = (1ULL << adev->gfx.num_compute_rings) - 1;
 	if ((val & mask) == 0)
 		return -EINVAL;
 
@@ -2149,7 +2149,7 @@ static int amdgpu_debugfs_compute_sched_mask_get(void *data, u64 *val)
 	for (i = 0; i < adev->gfx.num_compute_rings; ++i) {
 		ring = &adev->gfx.compute_ring[i];
 		if (ring->sched.ready)
-			mask |= 1 << i;
+			mask |= 1ULL << i;
 	}
 
 	*val = mask;
-- 
2.34.1



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