Work around UB in LMDB bindings #6211
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michaelsproul
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bug
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Thanks @jimmygchen for helping debug this. I'll have another follow-up PR that fixes the file descriptor leak in the iterated tests. I want to keep it separate from this PR because it involves |
jimmygchen
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Nice, let's deploy this fix to our testnet slasher. |
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@mergify queue |
✅ The pull request has been merged automaticallyThe pull request has been merged automatically at 0bb2386 |
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For reference, I think the exact type of UB triggered was:
From https://doc.rust-lang.org/reference/behavior-considered-undefined.html |
AgeManning
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Sep 3, 2024
* Work around UB in LMDB bindings
chong-he
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Nov 26, 2024
* Work around UB in LMDB bindings
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Issue Addressed
Fix a crazy memory corruption bug in the LMDB slasher impl.
Proposed Changes
Copy the contents of the cursor's
valueprior to returning it, so that LMDB can't mutate the data being pointed to when.delete_current()is called.Additional Info
This possibly explains the strange behaviour seen on some slasher nodes:
The bug had existed latently for a long time, but only now became executable with the refactor in: