Replaying firefox recording fails with: "eip registers do not match: syscall now: f7fdd1d0 and recorded: 555561d0"

[joneschrisg]

eip registers do not match: syscall now: f7fdd1d0 and recorded: 555561d0
[FATAL] (/home/cjones/rr/rr/src/replayer/rep_process_event.c:88: errno: None) [syscall number 11, state 1, trace file line 7]

This is execve, so something is going wrong in the rr child before firefox is loaded. Appears to be a regression.

[joneschrisg]

ld.so and the vdso seem to be mapped at different addresses during record and replay. Very odd ...

[joneschrisg]

OK, this is one of those creepy ones. I was making the recording with a script helper but then replaying it "by hand". The script helper invokes the rr binary directly, but when I run "by hand" I invoke rr through a symbolic link. Somehow that difference (or something like it) is causing the process to get a different address space layout.

When I record and replay by hand, all is well. Adding a script helper to replay and using helpers for both record and replay also is happy.