| Message ID | 20211026093407.11381-1-jani.nikula@intel.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | [v2] drm/i915/dp: fix integer overflow in 128b/132b data rate calculation | expand |
On Tue, Oct 26, 2021 at 12:34:07PM +0300, Jani Nikula wrote: > The intermediate value 1000000 * 10 * 9671 overflows 32 bits, so force > promotion to a bigger type. > > >From the logs: > > [drm:intel_dp_compute_config [i915]] DP link rate required 3657063 available -580783288 > > v2: Use mul_u32_u32() (Ville) > > Fixes: 48efd014f0ea ("drm/i915/dp: add max data rate calculation for UHBR rates") > Cc: Manasi Navare <manasi.d.navare@intel.com> > Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> > Signed-off-by: Jani Nikula <jani.nikula@intel.com> Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> > --- > drivers/gpu/drm/i915/display/intel_dp.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c > index f5dc2126d140..537c689a1528 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -352,7 +352,7 @@ intel_dp_max_data_rate(int max_link_rate, int max_lanes) > */ > int max_link_rate_kbps = max_link_rate * 10; > > - max_link_rate_kbps = DIV_ROUND_CLOSEST_ULL(max_link_rate_kbps * 9671, 10000); > + max_link_rate_kbps = DIV_ROUND_CLOSEST_ULL(mul_u32_u32(max_link_rate_kbps, 9671), 10000); > max_link_rate = max_link_rate_kbps / 8; > } > > -- > 2.30.2
On Tue, 26 Oct 2021, Ville Syrjälä <ville.syrjala@linux.intel.com> wrote: > On Tue, Oct 26, 2021 at 12:34:07PM +0300, Jani Nikula wrote: >> The intermediate value 1000000 * 10 * 9671 overflows 32 bits, so force >> promotion to a bigger type. >> >> >From the logs: >> >> [drm:intel_dp_compute_config [i915]] DP link rate required 3657063 available -580783288 >> >> v2: Use mul_u32_u32() (Ville) >> >> Fixes: 48efd014f0ea ("drm/i915/dp: add max data rate calculation for UHBR rates") >> Cc: Manasi Navare <manasi.d.navare@intel.com> >> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> >> Signed-off-by: Jani Nikula <jani.nikula@intel.com> > > Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com> Thanks, pushed. BR, Jani. > >> --- >> drivers/gpu/drm/i915/display/intel_dp.c | 2 +- >> 1 file changed, 1 insertion(+), 1 deletion(-) >> >> diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c >> index f5dc2126d140..537c689a1528 100644 >> --- a/drivers/gpu/drm/i915/display/intel_dp.c >> +++ b/drivers/gpu/drm/i915/display/intel_dp.c >> @@ -352,7 +352,7 @@ intel_dp_max_data_rate(int max_link_rate, int max_lanes) >> */ >> int max_link_rate_kbps = max_link_rate * 10; >> >> - max_link_rate_kbps = DIV_ROUND_CLOSEST_ULL(max_link_rate_kbps * 9671, 10000); >> + max_link_rate_kbps = DIV_ROUND_CLOSEST_ULL(mul_u32_u32(max_link_rate_kbps, 9671), 10000); >> max_link_rate = max_link_rate_kbps / 8; >> } >> >> -- >> 2.30.2
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index f5dc2126d140..537c689a1528 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -352,7 +352,7 @@ intel_dp_max_data_rate(int max_link_rate, int max_lanes) */ int max_link_rate_kbps = max_link_rate * 10; - max_link_rate_kbps = DIV_ROUND_CLOSEST_ULL(max_link_rate_kbps * 9671, 10000); + max_link_rate_kbps = DIV_ROUND_CLOSEST_ULL(mul_u32_u32(max_link_rate_kbps, 9671), 10000); max_link_rate = max_link_rate_kbps / 8; }
The intermediate value 1000000 * 10 * 9671 overflows 32 bits, so force promotion to a bigger type. From the logs: [drm:intel_dp_compute_config [i915]] DP link rate required 3657063 available -580783288 v2: Use mul_u32_u32() (Ville) Fixes: 48efd014f0ea ("drm/i915/dp: add max data rate calculation for UHBR rates") Cc: Manasi Navare <manasi.d.navare@intel.com> Cc: Ville Syrjälä <ville.syrjala@linux.intel.com> Signed-off-by: Jani Nikula <jani.nikula@intel.com> --- drivers/gpu/drm/i915/display/intel_dp.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)