Fix T81340: UBSan: load of value .. not a valid type for IDRecalcFlag
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Authored by Ankit Meel (ankitm) on Oct 1 2020, 1:17 AM.

Details

Reviewers: None
Maniphest Tasks: T81340: UBSan: several runtime errors at launch.

Summary

The value of flag is (-8392830)10 (ff7fef82)16, which points to
the problem in deg_builder.cc:237: flag |= id_orig->recalc; where
recalc is -8392830. That is a separate issue.

bitscan_forward_clear_i keeps reducing the value of current_flag
until the sign bit is cleared and long before that, the underlying
type of the enum overflows.

The warning:
depsgraph_tag.cc:367:7: runtime error: load of value 33554432, which
is not a valid value for type 'IDRecalcFlag'

Fix T81340 (partially)

Diff Detail

Repository

rB Blender

Branch

ubdeg (branched from master)

Build Status

Buildable 10498
Build 10498: arc lint + arc unit

Event Timeline

Ankit Meel (ankitm) requested review of this revision.Oct 1 2020, 1:17 AM

Ankit Meel (ankitm) created this revision.

Harbormaster completed remote builds in B10498: Diff 29438.Oct 1 2020, 1:17 AM

Ankit Meel (ankitm) mentioned this in T81340: UBSan: several runtime errors at launch. .Oct 1 2020, 1:24 AM

Campbell Barton (campbellbarton) added a subscriber: Campbell Barton (campbellbarton).Oct 1 2020, 5:48 AM

Campbell Barton (campbellbarton) added inline comments.

source/blender/depsgraph/intern/depsgraph_tag.cc
662–666	Since it's possible we some day use `(1 << 32u)` in `IDRecalcFlag` , wouldn't it be more future proof to use a `uint` here?

There are other problems in IDRecalcFlag related code and this patch is a duct tape.
Why does one part of the code do flag |= -8392830; ?
If all enumerators are positive, why not assert (or print a log at least) if a negative flag appears?
(minor) Why not use const for arguments ?

I'd rather abandon this and let someone else create a better fix.

Revision Contents
Changeset List

Path

Size

source/

blender/

depsgraph/

intern/

depsgraph_tag.cc

2 lines

Diff 29438

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source/blender/depsgraph/intern/depsgraph_tag.cc

Fix T81340: UBSan: load of value .. not a valid type for IDRecalcFlagAbandonedPublicActions