drm/amd/pm: Prevent division by zero

commit 7d641c2b83275d3b0424127b2e0d2d0f7dd82aef upstream.

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: b64625a303de ("drm/amd/pm: correct the address of Arcturus fan related registers")
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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/gpu/drm/amd/pm/swsmu/smu11/arcturus_ppt.c b/drivers/gpu/drm/amd/pm/swsmu/smu11/arcturus_ppt.c
index 4c58c2cd26d886273d9dbd3293a0cc6901499881..0cdf3257b19b3b5200da69b6d450c3561ef864a4 100644 (file)
--- a/drivers/gpu/drm/amd/pm/swsmu/smu11/arcturus_ppt.c
+++ b/drivers/gpu/drm/amd/pm/swsmu/smu11/arcturus_ppt.c
@@ -1274,6 +1274,9 @@ static int arcturus_set_fan_speed_rpm(struct smu_context *smu,
        uint32_t crystal_clock_freq = 2500;
        uint32_t tach_period;
 
+       if (!speed || speed > UINT_MAX/8)
+               return -EINVAL;
+
        tach_period = 60 * crystal_clock_freq * 10000 / (8 * speed);
        WREG32_SOC15(THM, 0, mmCG_TACH_CTRL_ARCT,
                     REG_SET_FIELD(RREG32_SOC15(THM, 0, mmCG_TACH_CTRL_ARCT),