Fix x86 exception handling edge case #113760
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When a NULL reference exception occurs in a JIT helper or a VSD stub, runtime pretends the exception occured in the managed caller. There is a bug on x86 Windows where the COMPlusThrowCallback considers that frame to be the frame where the exception actually occurred (based on the m_crawl.isFirst). In case the call to the helper is the last instruction in a try region, the exception handler lookup would reject that address and the exception may not get handled at the right place or at all. This change fixes it by ensuring that the m_crawl.isFirst is not set when the frame is not the frame of the failure. Close dotnet#113106
jkotas
approved these changes
Mar 21, 2025
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/ba-g the failure is #113785 |
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When a NULL reference exception occurs in a JIT helper or a VSD stub, runtime pretends the exception occurred in the managed caller. There is a bug on x86 Windows where the
COMPlusThrowCallbackconsiders that frame to be the frame where the exception actually occurred (based on them_crawl.isFirst). In case the call to the helper is the last instruction in a try region, the exception handler lookup would reject that address and the exception may not get handled at the right place or at all.This change fixes it by ensuring that the
m_crawl.isFirstis not set when the frame is not the frame of the failure.Close #113106