On Fri, 18 Nov 2022, coverity-bot <keescook@xxxxxxxxxxxx> wrote: > Hello! > > This is an experimental semi-automated report about issues detected by > Coverity from a scan of next-20221118 as part of the linux-next scan project: > https://scan.coverity.com/projects/linux-next-weekly-scan > > You're getting this email because you were associated with the identified > lines of code (noted below) that were touched by commits: > > Thu Nov 17 16:12:56 2022 +0200 > 62749912540b ("drm/i915/display: move hti under display sub-struct") > > Coverity reported the following: > > *** CID 1527374: Integer handling issues (BAD_SHIFT) > drivers/gpu/drm/i915/display/intel_hti.c:24 in intel_hti_uses_phy() > 18 if (INTEL_INFO(i915)->display.has_hti) > 19 i915->display.hti.state = intel_de_read(i915, HDPORT_STATE); > 20 } > 21 > 22 bool intel_hti_uses_phy(struct drm_i915_private *i915, enum phy phy) > 23 { > vvv CID 1527374: Integer handling issues (BAD_SHIFT) > vvv In expression "1UL << 2 * phy + 1", shifting by a negative amount has undefined behavior. The shift amount, "2 * phy + 1", is as little as -1. > 24 return i915->display.hti.state & HDPORT_ENABLED && > 25 i915->display.hti.state & HDPORT_DDI_USED(phy); > 26 } > 27 > 28 u32 intel_hti_dpll_mask(struct drm_i915_private *i915) > 29 { > > If this is a false positive, please let us know so we can mark it as > such, or teach the Coverity rules to be smarter. If not, please make > sure fixes get into linux-next. :) For patches fixing this, please > include these lines (but double-check the "Fixes" first): > > Reported-by: coverity-bot <keescook+coverity-bot@xxxxxxxxxxxx> > Addresses-Coverity-ID: 1527374 ("Integer handling issues") > Fixes: 62749912540b ("drm/i915/display: move hti under display sub-struct") Thanks for the report, fix at [1]. I realize I didn't use the suggested tags above. For one thing, we've never really logged any proprietary tools used. Looks like "Addresses-Coverity-ID:" is growing in popularity though. The Fixes: tag points at code refactoring, it was a pre-existing condition. BR, Jani. [1] https://patchwork.freedesktop.org/patch/msgid/20221122120948.3436180-1-jani.nikula@xxxxxxxxx > > This code appears to be safe currently (intel_hti_uses_phy() is never > called with PHY_NONE), but perhaps add an explicit check? > > if (WARN_ON(phy == PHY_NONE)) > return false; > > Thanks for your attention! -- Jani Nikula, Intel Open Source Graphics Center
