From: Denis Arefev <arefev@swemel.ru>
Date: Fri, 21 Mar 2025 10:52:33 +0000 (+0300)
Subject: drm/amd/pm: Prevent division by zero
X-Git-Tag: v5.4.293~39
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=6b9f9b998b107c7539f148a013d789ddb860c3b9;p=thirdparty%2Fkernel%2Fstable.git

drm/amd/pm: Prevent division by zero

[ Upstream commit 4e3d9508c056d7e0a56b58d5c81253e2a0d22b6c ]

The user can set any speed value.
If speed is greater than UINT_MAX/8, division by zero is possible.

Found by Linux Verification Center (linuxtesting.org) with SVACE.

Fixes: 031db09017da ("drm/amd/powerplay/vega20: enable fan RPM and pwm settings V2")
Signed-off-by: Denis Arefev <arefev@swemel.ru>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Cc: stable@vger.kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---

diff --git a/drivers/gpu/drm/amd/powerplay/hwmgr/vega20_thermal.c b/drivers/gpu/drm/amd/powerplay/hwmgr/vega20_thermal.c
index ce56b93871e8f..d057c6f7e1fce 100644
--- a/drivers/gpu/drm/amd/powerplay/hwmgr/vega20_thermal.c
+++ b/drivers/gpu/drm/amd/powerplay/hwmgr/vega20_thermal.c
@@ -189,7 +189,7 @@ int vega20_fan_ctrl_set_fan_speed_rpm(struct pp_hwmgr *hwmgr, uint32_t speed)
 	uint32_t tach_period, crystal_clock_freq;
 	int result = 0;
 
-	if (!speed)
+	if (!speed || speed > UINT_MAX/8)
 		return -EINVAL;
 
 	if (PP_CAP(PHM_PlatformCaps_MicrocodeFanControl)) {