SyzyASAN - ignore NULL pointer accesses?

[sigurasg]

SyzyASAN seems to be reporting NULL pointer, and near-NULL pointer accesses as ASAN issues. The first 64K of user memory is unmapped by default (convention?), so this is somewhat redundant. Maybe it's better to greenzone the first 64K in shadow and just let these crash.

[chhamilton]

Bruce Dawson suggested that we should never wrap the original exception, even if we've augmented the crash report with additional information. Wrapping page violations / null pointer dereferences / etc actually hides the underlying error, and they all bucket under the SyzyASAN UNKNOWN crash type. I think that's a great follow-up for plmonette's CL.

[sebmarchand]

Does that mean that we should maybe disable the unhandled exception filter ?

[chhamilton]

No, we still want the filter to be able to analyze memory and add information about memory corruption, etc. But we don't need to wrap the exception record with our own one in this case.

[chhamilton]

This has been partially addressed by plmonette's CL. However, to close this let's not wrap UnhandledExceptionFilter bugs at all, but rather only augment them.