[mono] Allocate helper page with mono_valloc so it doesn't confuse instruments#120060
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BrzVlad merged 2 commits intodotnet:mainfrom Sep 25, 2025
Merged
[mono] Allocate helper page with mono_valloc so it doesn't confuse instruments#120060BrzVlad merged 2 commits intodotnet:mainfrom
BrzVlad merged 2 commits intodotnet:mainfrom
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…net#119754)" This reverts commit 9031045.
mono_valloc uses mmap behind the scene.
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Pull Request Overview
This PR changes how the helper page is allocated in the mono runtime's process-wide memory barrier implementation to avoid confusing profiling instruments. The key change replaces posix_memalign with mono_valloc (which uses mmap) and restructures when memory protection is set.
- Replaces
posix_memalignallocation withmono_vallocto use mmap-based allocation - Moves memory protection setup to occur before page access rather than after
- Removes the protection restoration logic that was specifically added to avoid confusing profiling tools
Comments suppressed due to low confidence (1)
src/mono/mono/utils/mono-threads-posix.c:1
- The code writes to the helper page at line 304 but then immediately removes all access permissions at line 306. This creates a memory leak scenario where the page remains allocated but inaccessible for future barrier operations, potentially causing crashes on subsequent calls to this function.
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jkotas
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lateralusX
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/ba-g This change doesn't touch wasm bits. |
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/backport to release/10.0 |
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Started backporting to release/10.0: https://github.com/dotnet/runtime/actions/runs/18160368930 |
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mono_valloc uses mmap behind the scene.