Am 08.02.21 um 00:07 schrieb Colin King:
From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
The left shift of int 32 bit integer constant 1 is evaluated using 32
bit arithmetic and then assigned to an unsigned 64 bit integer. In the
case where *frag is 32 or more this can lead to an oveflow. Avoid this
by shifting 1ULL.
Well that can't happen. Take a look at the code in that function:
max_frag = 31;
...
if (*frag >= max_frag) {
*frag = max_frag;
*frag_end = end & ~((1ULL << max_frag) - 1);
} else {
*frag_end = start + (1 << *frag);
}
But I'm fine with applying the patch if it silences your warning.
Regards,
Christian.
Addresses-Coverity: ("Unintentional integer overflow")
Fixes: dfcd99f6273e ("drm/amdgpu: meld together VM fragment and huge page handling")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
index 9d19078246c8..53a925600510 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_vm.c
@@ -1412,7 +1412,7 @@ static void amdgpu_vm_fragment(struct amdgpu_vm_update_params *params,
*frag = max_frag;
*frag_end = end & ~((1ULL << max_frag) - 1);
} else {
- *frag_end = start + (1 << *frag);
+ *frag_end = start + (1ULL << *frag);
}
}
