Nouveau - Nov 2023 - [bug report] drm/nouveau/gsp/r535: add support for booting GSP-RM

Hello Ben Skeggs,

The patch 176fdcbddfd2: "drm/nouveau/gsp/r535: add support for
booting GSP-RM" from Sep 19, 2023 (linux-next), leads to the
following Smatch static checker warning:

	drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c:1016
r535_gsp_rpc_unloading_guest_driver()
	warn: 'rpc' isn't an ERR_PTR

drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c
    1010 static int
    1011 r535_gsp_rpc_unloading_guest_driver(struct nvkm_gsp *gsp, bool suspend)
    1012 {
    1013         rpc_unloading_guest_driver_v1F_07 *rpc;
    1014 
    1015         rpc = nvkm_gsp_rpc_get(gsp,
NV_VGPU_MSG_FUNCTION_UNLOADING_GUEST_DRIVER, sizeof(*rpc));

nvkm_gsp_rpc_get() returns NULL on error.

--> 1016         if (IS_ERR(rpc))
    1017                 return PTR_ERR(rpc);
    1018 
    1019         if (suspend) {
    1020                 rpc->bInPMTransition = 1;
    1021                 rpc->bGc6Entering = 0;
    1022                 rpc->newLevel =
NV2080_CTRL_GPU_SET_POWER_STATE_GPU_LEVEL_3;
    1023         } else {
    1024                 rpc->bInPMTransition = 0;
    1025                 rpc->bGc6Entering = 0;
    1026                 rpc->newLevel =
NV2080_CTRL_GPU_SET_POWER_STATE_GPU_LEVEL_0;
    1027         }
    1028 
    1029         return nvkm_gsp_rpc_wr(gsp, rpc, true);
    1030 }

regards,
dan carpenter

On Tue, 2023-11-07 at 17:34 +0300, Dan Carpenter wrote:
> Hello Ben Skeggs,
Hi,

FYI, Ben is not maintaining Nouveau anymore. The MAINTAINERS file has
been updated in that regard.

P.
> 
> The patch 176fdcbddfd2: "drm/nouveau/gsp/r535: add support for
> booting GSP-RM" from Sep 19, 2023 (linux-next), leads to the
> following Smatch static checker warning:
> 
> ????????drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c:1016
> r535_gsp_rpc_unloading_guest_driver()
> ????????warn: 'rpc' isn't an ERR_PTR
> 
> drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c
> ??? 1010 static int
> ??? 1011 r535_gsp_rpc_unloading_guest_driver(struct nvkm_gsp *gsp,
> bool suspend)
> ??? 1012 {
> ??? 1013???????? rpc_unloading_guest_driver_v1F_07 *rpc;
> ??? 1014 
> ??? 1015???????? rpc = nvkm_gsp_rpc_get(gsp,
> NV_VGPU_MSG_FUNCTION_UNLOADING_GUEST_DRIVER, sizeof(*rpc));
> 
> nvkm_gsp_rpc_get() returns NULL on error.
> 
> --> 1016???????? if (IS_ERR(rpc))
> ??? 1017???????????????? return PTR_ERR(rpc);
> ??? 1018 
> ??? 1019???????? if (suspend) {
> ??? 1020???????????????? rpc->bInPMTransition = 1;
> ??? 1021???????????????? rpc->bGc6Entering = 0;
> ??? 1022???????????????? rpc->newLevel >
NV2080_CTRL_GPU_SET_POWER_STATE_GPU_LEVEL_3;
> ??? 1023???????? } else {
> ??? 1024???????????????? rpc->bInPMTransition = 0;
> ??? 1025???????????????? rpc->bGc6Entering = 0;
> ??? 1026???????????????? rpc->newLevel >
NV2080_CTRL_GPU_SET_POWER_STATE_GPU_LEVEL_0;
> ??? 1027???????? }
> ??? 1028 
> ??? 1029???????? return nvkm_gsp_rpc_wr(gsp, rpc, true);
> ??? 1030 }
> 
> regards,
> dan carpenter
>

On Tue, Nov 07, 2023 at 05:34:43PM +0300, Dan Carpenter
wrote:
> Hello Ben Skeggs,
> 
> The patch 176fdcbddfd2: "drm/nouveau/gsp/r535: add support for
> booting GSP-RM" from Sep 19, 2023 (linux-next), leads to the
> following Smatch static checker warning:
> 
> 	drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c:1016
r535_gsp_rpc_unloading_guest_driver()
> 	warn: 'rpc' isn't an ERR_PTR
Some related bugs are:

drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c:1058 r535_gsp_rpc_set_registry()
warn: 'rpc' isn't an ERR_PTR
drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c:1273
r535_gsp_rpc_set_system_info() warn: 'info' isn't an ERR_PTR
drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c:611 r535_gsp_rpc_rm_alloc_get()
warn: 'rpc' isn't an ERR_PTR
drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c:667 r535_gsp_rpc_rm_ctrl_get()
warn: 'rpc' isn't an ERR_PTR
drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c:692 r535_gsp_rpc_get() warn:
'rpc' is an error pointer or valid
drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c:695 r535_gsp_rpc_get() error:
'rpc' dereferencing possible ERR_PTR()
drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c:735 r535_gsp_rpc_push() warn:
'next' isn't an ERR_PTR
drivers/gpu/drm/nouveau/nvkm/subdev/instmem/r535.c:69 fbsr_memlist() warn:
'rpc' isn't an ERR_PTR

regards,
dan carpenter

On 11/7/23 15:34, Dan Carpenter wrote:
> Hello Ben Skeggs,
> 
> The patch 176fdcbddfd2: "drm/nouveau/gsp/r535: add support for
> booting GSP-RM" from Sep 19, 2023 (linux-next), leads to the
> following Smatch static checker warning:
> 
> 	drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c:1016
r535_gsp_rpc_unloading_guest_driver()
> 	warn: 'rpc' isn't an ERR_PTR
> 
> drivers/gpu/drm/nouveau/nvkm/subdev/gsp/r535.c
>      1010 static int
>      1011 r535_gsp_rpc_unloading_guest_driver(struct nvkm_gsp *gsp, bool
suspend)
>      1012 {
>      1013         rpc_unloading_guest_driver_v1F_07 *rpc;
>      1014
>      1015         rpc = nvkm_gsp_rpc_get(gsp,
NV_VGPU_MSG_FUNCTION_UNLOADING_GUEST_DRIVER, sizeof(*rpc));
> 
> nvkm_gsp_rpc_get() returns NULL on error.
There are also code paths where it can return an ERR_PTR. I think we need to
check for IS_ERR_OR_NULL()...
> 
> --> 1016         if (IS_ERR(rpc))
>      1017                 return PTR_ERR(rpc);
>      1018
>      1019         if (suspend) {
>      1020                 rpc->bInPMTransition = 1;
>      1021                 rpc->bGc6Entering = 0;
>      1022                 rpc->newLevel =
NV2080_CTRL_GPU_SET_POWER_STATE_GPU_LEVEL_3;
>      1023         } else {
>      1024                 rpc->bInPMTransition = 0;
>      1025                 rpc->bGc6Entering = 0;
>      1026                 rpc->newLevel =
NV2080_CTRL_GPU_SET_POWER_STATE_GPU_LEVEL_0;
>      1027         }
>      1028
>      1029         return nvkm_gsp_rpc_wr(gsp, rpc, true);
>      1030 }
> 
> regards,
> dan carpenter