Fix bad interaction with Spectre mitigation and VirtualArray OOB resume #4682
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chakrabot
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Feb 15, 2018
… and VirtualArray OOB resume Merge pull request #4682 from MikeHolman:virtualspectre In case of VirtualArrays, we may have eliminated bound check and rely on our AV handling (as long as index is guaranteed to be within 4GB). However, with spectre mitigations we force OOB reads to nullptr. Our exception filter only handles AVs trying to read from the reserved region, so we end up crashing with nullptr deref instead of resuming. This change makes it so that we will only poison in case the index exceeds our 4GB reservation. OS: 15897366
chakrabot
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Feb 15, 2018
…mitigation and VirtualArray OOB resume Merge pull request #4682 from MikeHolman:virtualspectre In case of VirtualArrays, we may have eliminated bound check and rely on our AV handling (as long as index is guaranteed to be within 4GB). However, with spectre mitigations we force OOB reads to nullptr. Our exception filter only handles AVs trying to read from the reserved region, so we end up crashing with nullptr deref instead of resuming. This change makes it so that we will only poison in case the index exceeds our 4GB reservation. OS: 15897366
chakrabot
pushed a commit
that referenced
this pull request
Feb 15, 2018
…with Spectre mitigation and VirtualArray OOB resume Merge pull request #4682 from MikeHolman:virtualspectre In case of VirtualArrays, we may have eliminated bound check and rely on our AV handling (as long as index is guaranteed to be within 4GB). However, with spectre mitigations we force OOB reads to nullptr. Our exception filter only handles AVs trying to read from the reserved region, so we end up crashing with nullptr deref instead of resuming. This change makes it so that we will only poison in case the index exceeds our 4GB reservation. OS: 15897366
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In case of VirtualArrays, we may have eliminated bound check and rely on our AV handling (as long as index is guaranteed to be within 4GB).
However, with spectre mitigations we force OOB reads to nullptr. Our exception filter only handles AVs trying to read from the reserved region, so we end up crashing with nullptr deref instead of resuming.
This change makes it so that we will only poison in case the index exceeds our 4GB reservation.
OS: 15897366