[PATCH 5.15 098/167] drm/amd/pm: Prevent divide by zero

[Greg Kroah-Hartman]

From: Yefim Barashkin <mr.b34r@xxxxxxxxxxxx>

[ Upstream commit 0638c98c17aa12fe914459c82cd178247e21fb2b ]

divide error: 0000 [#1] SMP PTI
CPU: 3 PID: 78925 Comm: tee Not tainted 5.15.50-1-lts #1
Hardware name: MSI MS-7A59/Z270 SLI PLUS (MS-7A59), BIOS 1.90 01/30/2018
RIP: 0010:smu_v11_0_set_fan_speed_rpm+0x11/0x110 [amdgpu]

Speed is user-configurable through a file.
I accidentally set it to zero, and the driver crashed.

Reviewed-by: Evan Quan <evan.quan@xxxxxxx>
Reviewed-by: André Almeida <andrealmeid@xxxxxxxxxx>
Signed-off-by: Yefim Barashkin <mr.b34r@xxxxxxxxxxxx>
Signed-off-by: Alex Deucher <alexander.deucher@xxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
 drivers/gpu/drm/amd/pm/swsmu/smu11/smu_v11_0.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu11/smu_v11_0.c b/drivers/gpu/drm/amd/pm/swsmu/smu11/smu_v11_0.c
index e6c93396434f..614c3d049514 100644
--- a/drivers/gpu/drm/amd/pm/swsmu/smu11/smu_v11_0.c
+++ b/drivers/gpu/drm/amd/pm/swsmu/smu11/smu_v11_0.c
@@ -1235,6 +1235,8 @@ int smu_v11_0_set_fan_speed_rpm(struct smu_context *smu,
 	uint32_t crystal_clock_freq = 2500;
 	uint32_t tach_period;
 
+	if (speed == 0)
+		return -EINVAL;
 	/*
 	 * To prevent from possible overheat, some ASICs may have requirement
 	 * for minimum fan speed:
-- 
2.35.1