[PATCHv2] drm: zynqmp_dp: Fix integer overflow in zynqmp_dp_rate_get()

[PATCHv2] drm: zynqmp_dp: Fix integer overflow in zynqmp_dp_rate_get()

[Karol Przybylski]

This patch fixes a potential integer overflow in the zynqmp_dp_rate_get()

The issue comes up when the expression
drm_dp_bw_code_to_link_rate(dp->test.bw_code) * 10000 is evaluated using 32-bit
Now the constant is a compatible 64-bit type.

Resolves coverity issues: CID 1636340 and CID 1635811

Signed-off-by: Karol Przybylski <karprzy7@gmail.com>
Fixes: 28edaacb821c6 ("drm: zynqmp_dp: Add debugfs interface for compliance testing")
---
 drivers/gpu/drm/xlnx/zynqmp_dp.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/xlnx/zynqmp_dp.c b/drivers/gpu/drm/xlnx/zynqmp_dp.c
index 25c5dc61e..56a261a40 100644
--- a/drivers/gpu/drm/xlnx/zynqmp_dp.c
+++ b/drivers/gpu/drm/xlnx/zynqmp_dp.c
@@ -2190,7 +2190,7 @@ static int zynqmp_dp_rate_get(void *data, u64 *val)
 	struct zynqmp_dp *dp = data;
 
 	mutex_lock(&dp->lock);
-	*val = drm_dp_bw_code_to_link_rate(dp->test.bw_code) * 10000;
+	*val = drm_dp_bw_code_to_link_rate(dp->test.bw_code) * 10000ULL;
 	mutex_unlock(&dp->lock);
 	return 0;
 }
-- 
2.34.1

Re: [PATCHv2] drm: zynqmp_dp: Fix integer overflow in zynqmp_dp_rate_get()

[kernel test robot]

Hi,

Thanks for your patch.

FYI: kernel test robot notices the stable kernel rule is not satisfied.

The check is based on https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html#option-1

Rule: add the tag "Cc: stable@vger.kernel.org" in the sign-off area to have the patch automatically included in the stable tree.
Subject: [PATCHv2] drm: zynqmp_dp: Fix integer overflow in zynqmp_dp_rate_get()
Link: https://lore.kernel.org/stable/20241212095057.1015146-1-karprzy7%40gmail.com

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https://github.com/intel/lkp-tests/wiki