From: Arnd Bergmann <arnd@arndb.de>
Date: Thu, 2 Nov 2017 12:25:39 +0100
Subject: drm/amdgpu/virt: don't dereference undefined 'module' struct
Git-commit: e477e940dad1836c6f6d23353e424665b9316b6e
Patch-mainline: v4.15-rc1
References: FATE#326289 FATE#326079 FATE#326049 FATE#322398 FATE#326166

Accessing the THIS_MODULE directly is only possible when modules
are enabled, otherwise we get a build failure:

drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c: In function 'amdgpu_virt_init_data_exchange':
drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c:331:20: error: dereferencing pointer to incomplete type 'struct module'

Further, THIS_MODULE is NULL when the driver is built-in, so the
code would likely cause a NULL pointer dereference.

This adds an #ifdef check to avoid the compile-time error, plus
a NULL pointer check before dereferencing THIS_MODULE. It might
be better to find a way to avoid using the module version
altogether.

Fixes: 2dc8f81e4f82 ("drm/amdgpu: SR-IOV data exchange between PF&VF")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Reviewed-by: Harry Wentland <harry.wentland@amd.com>
Reviewed-By: Xiangliang Yu <Xiangliang.Yu@amd.com>

Acked-by: Petr Tesarik <ptesarik@suse.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_virt.c
@@ -328,9 +328,11 @@ void amdgpu_virt_init_data_exchange(stru
 					sizeof(amdgim_vf2pf_info));
 				AMDGPU_FW_VRAM_VF2PF_READ(adev, driver_version,
 					&str);
+#ifdef MODULE
 				if (THIS_MODULE->version != NULL)
 					strcpy(str, THIS_MODULE->version);
 				else
+#endif
 					strcpy(str, "N/A");
 				AMDGPU_FW_VRAM_VF2PF_WRITE(adev, driver_cert,
 					0);