From: Amit Kucheria <amit.kucheria@linaro.org>
To: Daniel Lezcano <daniel.lezcano@linaro.org>
Cc: Colin King <colin.king@canonical.com>,
Andy Gross <agross@kernel.org>, Zhang Rui <rui.zhang@intel.com>,
Eduardo Valentin <edubezval@gmail.com>,
Stephen Boyd <swboyd@chromium.org>,
Linux PM list <linux-pm@vger.kernel.org>,
linux-arm-msm <linux-arm-msm@vger.kernel.org>,
kernel-janitors@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH][next] drivers: thermal: tsens: fix potential integer overflow on multiply
Date: Wed, 30 Oct 2019 18:22:43 +0530 [thread overview]
Message-ID: <CAHLCerNvsZDT-FF4a+wsCqi4Fwf04e-rzaVq0qwsUtEWQL6kSQ@mail.gmail.com> (raw)
In-Reply-To: <cc9ea171-dfdc-f28e-59a4-26ab55155b8b@linaro.org>
On Wed, Oct 30, 2019 at 1:10 AM Daniel Lezcano
<daniel.lezcano@linaro.org> wrote:
>
> On 22/10/2019 13:49, Colin King wrote:
> > From: Colin Ian King <colin.king@canonical.com>
> >
> > Currently a multiply operation is being performed on two int values
> > and the result is being assigned to a u64, presumably because the
> > end result is expected to be probably larger than an int. However,
> > because the multiply is an int multiply one can get overflow. Avoid
> > the overflow by casting degc to a u64 to force a u64 multiply.
> >
> > Addresses-Coverity: ("Unintentional integer overflow")
> > Fixes: fbfe1a042cfd ("drivers: thermal: tsens: Add interrupt support")
> > Signed-off-by: Colin Ian King <colin.king@canonical.com>
> > ---
> > drivers/thermal/qcom/tsens-common.c | 2 +-
> > 1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/thermal/qcom/tsens-common.c b/drivers/thermal/qcom/tsens-common.c
> > index 03bf1b8133ea..3d7855106ecd 100644
> > --- a/drivers/thermal/qcom/tsens-common.c
> > +++ b/drivers/thermal/qcom/tsens-common.c
> > @@ -92,7 +92,7 @@ void compute_intercept_slope(struct tsens_priv *priv, u32 *p1,
> >
> > static inline u32 degc_to_code(int degc, const struct tsens_sensor *s)
> > {
> > - u64 code = (degc * s->slope + s->offset) / SLOPE_FACTOR;
> > + u64 code = ((u64)degc * s->slope + s->offset) / SLOPE_FACTOR;
>
>
> - u64 code = ((u64)degc * s->slope + s->offset) / SLOPE_FACTOR;
> + u64 code = div_u64(((u64)degc * s->slope + s->offset),
> SLOPE_FACTOR);
This implementation should handle 32-bit architectures too. Colin,
could you respin?
Regards,
Amit
prev parent reply other threads:[~2019-10-30 12:52 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-22 11:49 [PATCH][next] drivers: thermal: tsens: fix potential integer overflow on multiply Colin King
2019-10-22 12:46 ` walter harms
2019-10-29 19:40 ` Daniel Lezcano
2019-10-30 12:52 ` Amit Kucheria [this message]
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=CAHLCerNvsZDT-FF4a+wsCqi4Fwf04e-rzaVq0qwsUtEWQL6kSQ@mail.gmail.com \
--to=amit.kucheria@linaro.org \
--cc=agross@kernel.org \
--cc=colin.king@canonical.com \
--cc=daniel.lezcano@linaro.org \
--cc=edubezval@gmail.com \
--cc=kernel-janitors@vger.kernel.org \
--cc=linux-arm-msm@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-pm@vger.kernel.org \
--cc=rui.zhang@intel.com \
--cc=swboyd@chromium.org \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).