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fix(rax_tree): Fix crash caused by element destruction in RaxTreeMap #4228

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fix(rax_tree): Fix crash caused by element destruction in RaxTreeMap #4228

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10 changes: 6 additions & 4 deletions src/core/search/rax_tree.h
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Original file line number Diff line number Diff line change
Expand Up @@ -93,10 +93,12 @@ template <typename V> struct RaxTreeMap {
}

~RaxTreeMap() {
for (auto it = begin(); it != end(); ++it) {
V* ptr = &(*it).second;
std::allocator_traits<decltype(alloc_)>::destroy(alloc_, ptr);
alloc_.deallocate(ptr, 1);
while (true) {
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@kostasrim kostasrim Nov 29, 2024 •
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There are two things that concern me here:

  1. Looking at how raxRecursiveFree is implemented it calls free_callback(raxGetData(n) and what I introduced before seems to be on par in that respect because V* ptr = &(*it).second; is actually the result of raxGetData(n).
  2. Since we can reproduce this we should also include an isolated test to assert the root cause of the issue (my mistake not to suggest this earlier)

I would like to understand why deleting the result of raxGetData(n) result in segfault.

P.s. I also checked what Valkey is doing and indeed they use free_callback (they don't iterate like we do) but let's make sure we understand this

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@BagritsevichStepan BagritsevichStepan Nov 29, 2024 •
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raxFree passes NULL callback to the raxResursiveFree

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So it's not called there

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@BagritsevichStepan do you know how to reproduce this?

auto it = begin();
if (it == end())
break;
auto find_it = find((*it).first);
erase(find_it);
}
raxFree(tree_);
}
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