Possible allocator issues

managarm / mlibc

Portable C standard library

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Possible allocator issues #1107

Open Mathewnd opened 1 month ago

Mathewnd commented 1 month ago

While building GCC in Astral, mlibc accesses invalid memory while allocating memory for the application. The fault happens in frigg's rbtree implementation.

From what I have managed to gather, this is what happens:

Some memory still being used by the allocator's rbtree is unmapped here.
When the application calls malloc, the rbtree function faults, as it tries to access that unmapped range.

Geertiebear commented 1 month ago

Frigg has allocation tracing capabilities, it would be useful for debugging if such a trace could be acquired for this issue. Without this I suspect this will be exceedingly difficult to debug, especially because the Frigg allocator is quite well tested.

Mathewnd commented 1 month ago

Still don't have a trace. However, enabling FRG_SLAB_TRACK_REGIONS causes the following assertion to fail: /sysroot/usr/share/mlibc-build/frigg/include/frg/rbtree.hpp:213: Assertion 'grand && h(grand)->color == color_type::black' failed! This is due to h(grand)->color being color_type::red