[AMD Official Use Only - General] Hi Lijo, -----Original Message----- From: amd-gfx <amd-gfx-bounces@xxxxxxxxxxxxxxxxxxxxx> On Behalf Of Lazar, Lijo Sent: Friday, May 10, 2024 3:16 PM To: amd-gfx@xxxxxxxxxxxxxxxxxxxxx Subject: Re: [PATCH 19/22] drm/amdgpu: Fix the warning division or modulo by zero for the variable num_xcc_per_xcp On 5/10/2024 8:20 AM, Jesse Zhang wrote: > Dividing expression num_xcc_per_xcp which may be zero has undefined behavior. > > Signed-off-by: Jesse Zhang <Jesse.Zhang@xxxxxxx> > --- > drivers/gpu/drm/amd/amdgpu/aqua_vanjaram.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/amd/amdgpu/aqua_vanjaram.c > b/drivers/gpu/drm/amd/amdgpu/aqua_vanjaram.c > index 414ea3f560a7..5752c6760992 100644 > --- a/drivers/gpu/drm/amd/amdgpu/aqua_vanjaram.c > +++ b/drivers/gpu/drm/amd/amdgpu/aqua_vanjaram.c > @@ -522,6 +522,9 @@ static int aqua_vanjaram_switch_partition_mode(struct amdgpu_xcp_mgr *xcp_mgr, > goto unlock; > > num_xcc_per_xcp = __aqua_vanjaram_get_xcc_per_xcp(xcp_mgr, mode); > + if (!num_xcc_per_xcp) > + goto unlock; > + This won't happen as the mode is validated before and for each valid mode a non-zero num_xcc_per_xcp is expected. To satisfy the warning-checker, before going to unlock use a proper 'ret' value also (otherwise it will look odd). [Zhang, Jesse(Jie)] Is that possible? When the initialization mode is AMDGPU_AUTO_COMPUTE_PARTITION_MODE, and get AMDGPU_UNKNOWN_COMPUTE_PARTITION_MODE through __aqua_vanjaram_get_auto_mode. If so, it will skip the valid mode function (__aqua_vanjaram_is_valid_mode). Thanks Jesse Thanks, Lijo > if (adev->gfx.funcs->switch_partition_mode) > adev->gfx.funcs->switch_partition_mode(xcp_mgr->adev, > num_xcc_per_xcp);
