Re: [Valgrind-users] Jump to invalid address

[John R. <jr...@bi...>]

> (x86, gcc, valgrind v3.10.0)

Thank you for stating that information about the environment!
[Sometimes the output from "gcc --version" and "/lib*/libc.so.N"
also matters, but not in this case.]

> ==20897== Jump to the invalid address stated on the next line
> ==20897==    at 0x810CFFFF: ???
> ==20897==  Address 0x810cffff is not stack'd, malloc'd or (recently) free'd

In general, run with --vgdb-error=0 which enables simultaneous gdb and memcheck.
(Hint: after the initial attach, then gdb is waiting for commands and "continue".)
Then you can plant gdb breakpoints and watch as execution proceeds,
in order to bound and narrow the scope of the problem.

Add a subroutine which turns on the hardware feature which records successful
branches ("branch trace buffer").  This requires a trek through documentation
about the specific CPU and the Linux 'perf' subsystem.