[mono] Fix race during mono_image_storage_open #55201
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* The mono_refcount_inc call in mono_image_storage_trypublish or mono_image_storage_tryaddref may abort when racing against a mono_image_storage_dtor that already decremented the refcount.
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This race triggered in some cases when building aspnetcore using a Mono-based dotnet host SDK. The problem is that Fixed by detecting that case via
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…debugger_custom_views * 'main' of github.com:thaystg/runtime: (125 commits) [wasm] [debugger] Support method calls (dotnet#55458) [debugger] Fix debugging after hot reloading (dotnet#55599) Inliner: Extend IL limit for profiled call-sites, allow inlining for switches. (dotnet#55478) DiagnosticSourceEventSource supports base class properties (dotnet#55613) [mono] Fix race during mono_image_storage_open (dotnet#55201) [mono] Add wrapper info for native func wrappers. (dotnet#55602) H/3 and Quic AppContext switch (dotnet#55332) Compression.ZipFile support for Unix Permissions (dotnet#55531) [mono] Fix skipping of static methods during IMT table construction. (dotnet#55610) Combine System.Private.Xml TrimmingTests projects (dotnet#55606) fix name conflict with Configuration class (dotnet#55597) Finish migrating RSAOpenSsl from RSA* to EVP_PKEY* Disable generic math (dotnet#55540) Obsolete CryptoConfig.EncodeOID (dotnet#55592) Address System.Net.Http.WinHttpHandler's nullable warnings targeting .NETCoreApp (dotnet#54995) Enable Http2_MultipleConnectionsEnabled_ConnectionLimitNotReached_ConcurrentRequestsSuccessfullyHandled (dotnet#55572) Fix Task.WhenAny failure mode when passed ICollection of zero tasks (dotnet#55580) Consume DistributedContextPropagator in DiagnosticsHandler (dotnet#55392) Add property ordering feature (dotnet#55586) Reduce subtest count in Reflection (dotnet#55537) ...
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mono_image_storage_tryaddref may abort when racing against a
mono_image_storage_dtor that already decremented the refcount.
This race triggered in some cases when building aspnetcore using a Mono-based dotnet host SDK. The problem is that
mono_image_storage_closeruns outside themono_images_storage_lock(and this may be unavoidable due to lock ordering concerns). Therefore, we can have a refcount that was already decremented to zero, but beforemono_image_storage_dtorfinishes removing the object fromimages_storage_hash, a parallelmono_image_storage_trypublishmay have retrieved it from there. In that case, themono_refcount_inccall will abort.Fixed by detecting that case via
mono_refcount_tryincinstead, and simply treating the object as if it had already been removed. It will in time actually get removed, either by the parallelmono_image_storage_dtor, or else by theg_hash_table_insertinmono_image_storage_trypublish(which will safely replace it with the new object, andmono_image_storage_dtorwill then detect that and skip removal).