[PATCH 6.1 0822/1887] drm/amd/pm: fix null pointer access

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

6.1-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Umio Yasuno <coelacanth_dream@protonmail.com>

[ Upstream commit d524d40e3a6152a3ea1125af729f8cd8ca65efde ]

Writing a string without delimiters (' ', '\n', '\0') to the under
gpu_od/fan_ctrl sysfs or pp_power_profile_mode for the CUSTOM profile
will result in a null pointer dereference.

Closes: https://gitlab.freedesktop.org/drm/amd/-/issues/4401
Signed-off-by: Umio Yasuno <coelacanth_dream@protonmail.com>
Acked-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 drivers/gpu/drm/amd/pm/amdgpu_pm.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/amd/pm/amdgpu_pm.c b/drivers/gpu/drm/amd/pm/amdgpu_pm.c
index 500cbd1572374..1eaf20cad9fa1 100644
--- a/drivers/gpu/drm/amd/pm/amdgpu_pm.c
+++ b/drivers/gpu/drm/amd/pm/amdgpu_pm.c
@@ -1436,6 +1436,8 @@ static ssize_t amdgpu_set_pp_power_profile_mode(struct device *dev,
 			if (ret)
 				return -EINVAL;
 			parameter_size++;
+			if (!tmp_str)
+				break;
 			while (isspace(*tmp_str))
 				tmp_str++;
 		}
-- 
2.53.0