[release/7.0] Make DacValidateMD more resilient to invalid MethodDesc #79862
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The DacValidateMD is not resilient to invalid MethodDesc that contains NULL in its m_pMethTab field. It was found when using the ClrMD in the BenchmarkDotNet disassembler code which is trying to find if some constants in the code represent MethodDesc so that it can dump the related method name. This change fixes it by checking the MethodTable after it is extracted from the MethodDesc. There are two values that are not translated between the target and the debugger sides - NULL and -1. So I have added handling both as invalid there.
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Tagging subscribers to this area: @tommcdon Issue DetailsBackport of #79846 to release/7.0 /cc @janvorli Customer ImpactTestingRiskIMPORTANT: Is this backport for a servicing release? If so and this change touches code that ships in a NuGet package, please make certain that you have added any necessary package authoring and gotten it explicitly reviewed.
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mikem8361
approved these changes
Dec 20, 2022
hoyosjs
approved these changes
Dec 21, 2022
jeffschwMSFT
approved these changes
Jan 3, 2023
rbhanda
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Servicing-approved
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Approved by Tactics (7.0.3). |
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Backport of #79846 to release/7.0
/cc @janvorli
Customer Impact
BenchmarkDotNet crashes when attempting to translate addresses to methods in its disassembly feature
Testing
BenchmarkDotNet tests
Risk
Very low, it just explicitly detects NULL
MethodTableinMethodDescas invalid. Without this detection, theDacValidateMDwhen passed an invalidMethodDescwith NULLMethodTablejust crashes the process with AV. This change is in DAC only.