ide: fix drive head toctou bug on enlightened path (#3535)#4019
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babayet2 wants to merge 1 commit into
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ide: fix drive head toctou bug on enlightened path (#3535)#4019babayet2 wants to merge 1 commit into
babayet2 wants to merge 1 commit into
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The enlightened path in the IDE implementation is supposed to check whether the drive is busy, and bail out if so. We were checking if the drive is busy before switching the device head, meaning we could mistakenly go further down the enlightened path, even when the drive was busy. Fixed.
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Pull request overview
This PR fixes a correctness issue in the IDE device’s “enlightened” I/O path by ensuring the drive-busy/error check is performed after selecting the target drive via the Device/Head register, preventing the command from proceeding based on the status of the previously-selected drive.
Changes:
- Move the
current_drive_status()busy/error guard to occur after the Device/Head register write, so the check applies to the intended drive. - Preserve the existing early-return behavior (ignore enlightened command) when the selected drive is in error (
ERR) or has a pending command (BSY/DRQ).
smalis-msft
approved these changes
Jul 24, 2026
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This is a clean cherry-pick of #3535
The enlightened path in the IDE implementation is supposed to check whether the drive is busy, and bail out if so.
We were checking if the drive is busy before switching the device head, meaning we could mistakenly go further down the enlightened path, even when the drive was busy. Fixed.