On Mon, Mar 02, 2020 at 08:39:37PM -0800, Kees Cook wrote: > On Wed, Feb 19, 2020 at 10:22:29PM -0800, Kees Cook wrote: > > Variables declared in a switch statement before any case statements > > cannot be automatically initialized with compiler instrumentation (as > > they are not part of any execution flow). With GCC's proposed automatic > > stack variable initialization feature, this triggers a warning (and they > > don't get initialized). Clang's automatic stack variable initialization > > (via CONFIG_INIT_STACK_ALL=y) doesn't throw a warning, but it also > > doesn't initialize such variables[1]. Note that these warnings (or silent > > skipping) happen before the dead-store elimination optimization phase, > > so even when the automatic initializations are later elided in favor of > > direct initializations, the warnings remain. > > > > To avoid these problems, move such variables into the "case" where > > they're used or lift them up into the main function body. > > > > drivers/gpu/drm/drm_edid.c: In function ‘drm_edid_to_eld’: > > drivers/gpu/drm/drm_edid.c:4395:9: warning: statement will never be executed [-Wswitch-unreachable] > > 4395 | int sad_count; > > | ^~~~~~~~~ > > > > [1] https://bugs.llvm.org/show_bug.cgi?id=44916 > > > > Signed-off-by: Kees Cook <keescook@xxxxxxxxxxxx> > > Ping. Can someone pick this up, please? > > Thanks! > > -Kees > > > --- > > drivers/gpu/drm/drm_edid.c | 5 +++-- > > 1 file changed, 3 insertions(+), 2 deletions(-) > > > > diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c > > index 805fb004c8eb..2941b65b427f 100644 > > --- a/drivers/gpu/drm/drm_edid.c > > +++ b/drivers/gpu/drm/drm_edid.c > > @@ -4392,9 +4392,9 @@ static void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid) > > dbl = cea_db_payload_len(db); > > > > switch (cea_db_tag(db)) { > > - int sad_count; > > + case AUDIO_BLOCK: { I've never been a fan of {} inside switch statements. I'd just move this one level up. > > > > - case AUDIO_BLOCK: > > + int sad_count; > > /* Audio Data Block, contains SADs */ > > sad_count = min(dbl / 3, 15 - total_sad_count); > > if (sad_count >= 1) > > @@ -4402,6 +4402,7 @@ static void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid) > > &db[1], sad_count * 3); > > total_sad_count += sad_count; > > break; > > + } > > case SPEAKER_BLOCK: > > /* Speaker Allocation Data Block */ > > if (dbl >= 1) > > > > -- > Kees Cook > _______________________________________________ > dri-devel mailing list > dri-devel@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/dri-devel -- Ville Syrjälä Intel _______________________________________________ dri-devel mailing list dri-devel@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/dri-devel
