[PATCH v2] drm/amdgpu: Avoid possible buffer overflow
Su Hui
suhui at nfschina.com
Mon Aug 21 07:37:28 UTC 2023
smatch error:
drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c:1257 amdgpu_discovery_reg_base_init() error:
testing array offset 'adev->vcn.num_vcn_inst' after use.
change the assignment order to avoid buffer overflow.
Fixes: c40bdfb2ffa4 ("drm/amdgpu: fix incorrect VCN revision in SRIOV")
Signed-off-by: Su Hui <suhui at nfschina.com>
---
changes in v2:
- fix the error about ip->revision (thanks to Christophe JAILLET).
drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
index 8e1cfc87122d..b07bfd106a9b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_discovery.c
@@ -1250,11 +1250,10 @@ static int amdgpu_discovery_reg_base_init(struct amdgpu_device *adev)
* 0b10 : encode is disabled
* 0b01 : decode is disabled
*/
- adev->vcn.vcn_config[adev->vcn.num_vcn_inst] =
- ip->revision & 0xc0;
- ip->revision &= ~0xc0;
if (adev->vcn.num_vcn_inst <
AMDGPU_MAX_VCN_INSTANCES) {
+ adev->vcn.vcn_config[adev->vcn.num_vcn_inst] =
+ ip->revision & 0xc0;
adev->vcn.num_vcn_inst++;
adev->vcn.inst_mask |=
(1U << ip->instance_number);
@@ -1265,6 +1264,7 @@ static int amdgpu_discovery_reg_base_init(struct amdgpu_device *adev)
adev->vcn.num_vcn_inst + 1,
AMDGPU_MAX_VCN_INSTANCES);
}
+ ip->revision &= ~0xc0;
}
if (le16_to_cpu(ip->hw_id) == SDMA0_HWID ||
le16_to_cpu(ip->hw_id) == SDMA1_HWID ||
--
2.30.2
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