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8271486: [lworld] Memory corruption due to out of bound access in MacroAssembler::move_helper #507

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@TobiHartmann TobiHartmann commented Jul 29, 2021

While debugging weird crashes that only showed up when merging current mainline with lworld, I've noticed that we are writing outside of the reg_state array in MacroAssembler::move_helper because from->value() is -1 (OptoReg::BAD_REG):

// Update register states
reg_state[from->value()] = reg_writable;
reg_state[to->value()] = reg_written;
return true;

The register is invalid because it belongs to the second half of a T_LONG or T_DOUBLE argument in the calling convention and should simply be ignored. I've also added asserts to catch similar issues in the future.

Thanks,
Tobias


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  • Change must not contain extraneous whitespace

Issue

  • JDK-8271486: [lworld] Memory corruption due to out of bound access in MacroAssembler::move_helper

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Checkout this PR locally:
$ git fetch https://git.openjdk.java.net/valhalla pull/507/head:pull/507
$ git checkout pull/507

Update a local copy of the PR:
$ git checkout pull/507
$ git pull https://git.openjdk.java.net/valhalla pull/507/head

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Checkout this PR locally:
$ git pr checkout 507

View PR using the GUI difftool:
$ git pr show -t 507

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Download this PR as a diff file:
https://git.openjdk.java.net/valhalla/pull/507.diff

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bridgekeeper bot commented Jul 29, 2021

👋 Welcome back thartmann! A progress list of the required criteria for merging this PR into lworld will be added to the body of your pull request. There are additional pull request commands available for use with this pull request.

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openjdk bot commented Jul 29, 2021

@TobiHartmann This change now passes all automated pre-integration checks.

ℹ️ This project also has non-automated pre-integration requirements. Please see the file CONTRIBUTING.md for details.

After integration, the commit message for the final commit will be:

8271486: [lworld] Memory corruption due to out of bound access in MacroAssembler::move_helper

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mlbridge bot commented Jul 29, 2021

Webrevs

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TobiHartmann commented Jul 29, 2021

/integrate

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openjdk bot commented Jul 29, 2021

Going to push as commit 233d7bb.

@openjdk openjdk bot closed this Jul 29, 2021
@openjdk openjdk bot added integrated and removed ready rfr labels Jul 29, 2021
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openjdk bot commented Jul 29, 2021

@TobiHartmann Pushed as commit 233d7bb.

💡 You may see a message that your pull request was closed with unmerged commits. This can be safely ignored.

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