2020-11-06 14:51:35

by Georgi Djakov

Subject: [PATCH] interconnect: qcom: msm8974: Prevent integer overflow in rate

When sync_state support got introduced recently, by default we try to
set the NoCs to run initially at maximum rate. But as these values are
aggregated, we may end with a really big clock rate value, which is
then converted from "u64" to "long" during the clock rate rounding.
But on 32bit platforms this may result an overflow. Fix it by making
sure that the rate is within range.

Reported-by: Luca Weiss <[email protected]>
Fixes: b1d681d8d324 ("interconnect: Add sync state support")
Signed-off-by: Georgi Djakov <[email protected]>
---
drivers/interconnect/qcom/msm8974.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/drivers/interconnect/qcom/msm8974.c b/drivers/interconnect/qcom/msm8974.c
index 3a313e11e73d..b6b639dad691 100644
--- a/drivers/interconnect/qcom/msm8974.c
+++ b/drivers/interconnect/qcom/msm8974.c
@@ -618,6 +618,8 @@ static int msm8974_icc_set(struct icc_node *src, struct icc_node *dst)

do_div(rate, src_qn->buswidth);

+ rate = min_t(u32, rate, INT_MAX);
+
if (src_qn->rate == rate)
return 0;

@@ -758,6 +760,7 @@ static struct platform_driver msm8974_noc_driver = {
.driver = {
.name = "qnoc-msm8974",
.of_match_table = msm8974_noc_of_match,
+ .sync_state = icc_sync_state,
},
};
module_platform_driver(msm8974_noc_driver);

2020-11-07 00:46:08

by Brian Masney

Subject: Re: [PATCH] interconnect: qcom: msm8974: Prevent integer overflow in rate

On Fri, Nov 06, 2020 at 04:48:47PM +0200, Georgi Djakov wrote:
> When sync_state support got introduced recently, by default we try to
> set the NoCs to run initially at maximum rate. But as these values are
> aggregated, we may end with a really big clock rate value, which is
> then converted from "u64" to "long" during the clock rate rounding.
> But on 32bit platforms this may result an overflow. Fix it by making
> sure that the rate is within range.
>
> Reported-by: Luca Weiss <[email protected]>
> Fixes: b1d681d8d324 ("interconnect: Add sync state support")
> Signed-off-by: Georgi Djakov <[email protected]>

Reviewed-by: Brian Masney <[email protected]>