| Message ID | 20241115141449.709-1-m.masimov@maxima.ru (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v3] drm/mgag200: Apply upper limit for clock variable | expand |
On 15/11/2024 15:14, Murad Masimov wrote: > If the value of the clock variable is higher than 800000, the value of the > variable m, which is used as a divisor, will remain zero, because > (clock * testp) will be higher than vcomax in every loop iteration, which > leads to skipping every iteration and leaving variable m unmodified. > > Return -EINVAL just after the loop, if m is still 0. > > Found by Linux Verification Center (linuxtesting.org) with SVACE. Thanks for this patch. Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com> > > Fixes: e829d7ef9f17 ("drm/mgag200: Add support for a new rev of G200e") > Signed-off-by: Murad Masimov <m.masimov@maxima.ru> > --- > drivers/gpu/drm/mgag200/mgag200_g200se.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/drivers/gpu/drm/mgag200/mgag200_g200se.c b/drivers/gpu/drm/mgag200/mgag200_g200se.c > index 7a32d3b1d226..4d65ead63d66 100644 > --- a/drivers/gpu/drm/mgag200/mgag200_g200se.c > +++ b/drivers/gpu/drm/mgag200/mgag200_g200se.c > @@ -249,6 +249,9 @@ static int mgag200_g200se_04_pixpllc_atomic_check(struct drm_crtc *crtc, > } > } > > + if (m == 0) > + return -EINVAL; > + > fvv = pllreffreq * n / m; > fvv = (fvv - 800000) / 50000; > if (fvv > 15) > -- > 2.39.2 >
diff --git a/drivers/gpu/drm/mgag200/mgag200_g200se.c b/drivers/gpu/drm/mgag200/mgag200_g200se.c index 7a32d3b1d226..4d65ead63d66 100644 --- a/drivers/gpu/drm/mgag200/mgag200_g200se.c +++ b/drivers/gpu/drm/mgag200/mgag200_g200se.c @@ -249,6 +249,9 @@ static int mgag200_g200se_04_pixpllc_atomic_check(struct drm_crtc *crtc, } } + if (m == 0) + return -EINVAL; + fvv = pllreffreq * n / m; fvv = (fvv - 800000) / 50000; if (fvv > 15)
If the value of the clock variable is higher than 800000, the value of the variable m, which is used as a divisor, will remain zero, because (clock * testp) will be higher than vcomax in every loop iteration, which leads to skipping every iteration and leaving variable m unmodified. Return -EINVAL just after the loop, if m is still 0. Found by Linux Verification Center (linuxtesting.org) with SVACE. Fixes: e829d7ef9f17 ("drm/mgag200: Add support for a new rev of G200e") Signed-off-by: Murad Masimov <m.masimov@maxima.ru> --- drivers/gpu/drm/mgag200/mgag200_g200se.c | 3 +++ 1 file changed, 3 insertions(+) -- 2.39.2