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cam: fix UB behavior
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Authored by imp on Jun 21 2021, 6:01 PM.

Details

Reviewers
ken
mav
scottl
Group Reviewers
cam
Commits
rG56e1161b09c3: cam: fix UB behavior
Summary

The trick of subtracting one from the poitner returned from malloc
results in undefined behavior:

C89: 3.3.6 Unless both the pointer operand and the result point to a
member of the same array object, or one past the last member of the
array object, the behavior is undefined.

Instead, allocate 1 extra element and stop adjusting the pointer. While
a little wasteful, the extra is in the noise on today's systems.

Sponsored by: Netflix

Diff Detail

Repository
rG FreeBSD src repository
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Automatic diff as part of commit; lint not applicable.
Unit
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Event Timeline

imp requested review of this revision.Jun 21 2021, 6:01 PM

Thank you. This stuff always broke my brain.

This revision is now accepted and ready to land.Jun 24 2021, 3:11 AM
This revision was automatically updated to reflect the committed changes.