Suppress MSAN false positives from uninstrumented 3rd-party libraries?

[carlosgalvezp]

I understand that in order to use MSAN, the entire application (including dependencies) must be compiled with instrumentation, otherwise we get false positives.

Often times, this is not possible, and as such it creates a really high bar to be able to use MSAN in a real-world project. For example, the only reason we can't dump Valgrind just yet is we can't use MSAN.

Would it be possible instead to just be able to suppress those warnings in external libraries? I tried playing a bit with the -fsanitize-ignorelist option but I still got warnings even if I suppressed everything (maybe I used that incorrectly).

Thanks!

[vitalybuka]

You can suppress this way only issues in instrumented code.
It does not help with prebuild libs.

you can try to unpoison all data you get from the 3rd party lib with https://github.com/google/sanitizers/wiki/memorysanitizer#interface

But it still may fail if the lib calls into some LIBC functions.