[release/6.0] Add explicit null-check for tailcalls to VSD #62769
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There is already a comment that this is necessary, but it is only being done for x86 tailcalls via jit helper. Do it for normal tailcalls to VSD as well. Fix #61486
ghost
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area-CodeGen-coreclr
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Tagging subscribers to this area: @JulieLeeMSFT Issue DetailsBackport of #62719 to release/6.0 /cc @jakobbotsch Customer ImpactTestingRisk
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jkotas
approved these changes
Dec 14, 2021
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@jeffschwMSFT for awareness and approval. |
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Note that #62058 was reopened, so we may wish to hold off on this until that has been investigated further. |
jeffschwMSFT
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This can be merged. The other issue @jakobbotsch mentioned as reopened turned out to be unrelated and I am just about to create a PR and then a porting PR for it. |
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Approved offline |
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Backport of #62719 to release/6.0
/cc @jakobbotsch
Customer Impact
Certain reflection invocations and exception handling patterns that should throw NullReferenceException may instead crash the runtime due to an interaction between tailcalls to interface methods with a null receiver, and how the runtime maps access violations to NRE. Hit by customer in #61486.
Testing
Regression test included.
Regression
The same case reproduces in .NET 5, however the issue may be more common in .NET 6 because the JIT tailcalls more often.
Risk
Low, this changes the JIT to null-check ahead of time in this particular case.