[PLAT-3596] Fix reporting of mach exception code and subcode #806
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kstenerud
requested changes
Sep 16, 2020
Bugsnag/KSCrash/Source/KSCrash/Recording/Sentry/BSG_KSCrashSentry_MachException.c
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nickdowell
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kattrali
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kattrali
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kstenerud
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This was referenced Oct 1, 2020
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Goal
This change brings in some improvements to mach exception handling that were made in KSCrash
These changes fix the parsing of mach exception
codeandsubcodevalues.Prior to these changes, for a
EXC_BAD_ACCESSexception, thesubcodedid not contain the expected memory address. The exception handler was expecting the kernel to send 64-bit values, but 32-bit values were being sent instead because theMACH_EXCEPTION_CODESflag was not specified when registering the exception handler. There was also a struct padding issue (fixed by adding#pragma pack(4)) that was causing the exception handler to read values from the wrong offset, resulting in the memory address coming through ascodeandsubcodeto always contain the value0x8.Testing
I verified manually, using the example app, that the
EXC_BAD_ACCESSmach exception is reported to the dashboard. The dashboard is now correctly identifying and displaying the memory address that the app tried to access.