Fix dictionary use-after-free in active expire and make kvstore iter to respect EMPTY flag#13135
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After redis#13072, there is an use-after-free error. In expireScanCallback, we will delete the dict, and then in dictScan we will continue to use the dict, like we will doing `dictResumeRehashing(d)` in the end, this casued an error. In this PR, in freeDictIfNeeded, if the dict's pauserehash is set, don't delete the dict yet, and then when scan returns try to delete it again.
madolson
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Mar 13, 2024
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it's a shame this error made it passed the PR CI. either way, let's not delay the fix. what's holding us back? |
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ok, just 1.3s, i think we can remove the slow flag. I made some changes related to iter to respect the empty flag, please review. |
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…to respect EMPTY flag (redis#13135) After redis#13072, there is an use-after-free error. In expireScanCallback, we will delete the dict, and then in dictScan we will continue to use the dict, like we will doing `dictResumeRehashing(d)` in the end, this casued an error. In this PR, in freeDictIfNeeded, if the dict's pauserehash is set, don't delete the dict yet, and then when scan returns try to delete it again. At the same time, we noticed that there will be similar problems in iterator. We may also delete elements during the iteration process, causing the dict to be deleted, so the part related to iter in the PR has also been modified. dictResetIterator was also missing from the previous kvstoreIteratorNextDict, we currently have no scenario that elements will be deleted in kvstoreIterator process, deal with it together to avoid future problems. Added some simple tests to verify the changes. In addition, the modification in redis#13072 omitted initTempDb and emptyDbAsync, and they were also added. This PR also remove the slow flag from the expire test (consumes 1.3s) so that problems can be found in CI in the future.
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After #13072, there is an use-after-free error. In expireScanCallback, we
will delete the dict, and then in dictScan we will continue to use the dict,
like we will doing
dictResumeRehashing(d)in the end, this casued an error.In this PR, in freeDictIfNeeded, if the dict's pauserehash is set, don't
delete the dict yet, and then when scan returns try to delete it again.
At the same time, we noticed that there will be similar problems in iter.
We may also delete elements during the iteration process, causing the dict
to be deleted, so the part related to iter in the PR has also been modified.
dictResetIterator was also missing from the previous kvstoreIteratorNextDict,
we currently have no scenario that elements will be deleted in kvstoreIterator
process, deal with it together to avoid future problems. Added some simple
tests to verify the changes.
In addition, the modification in #13072 omitted initTempDb and emptyDbAsync,
and they were also added. This PR also remove the slow flag from the expire
test (consumes 1.3s) so that problems can be found in CI in the future.