[ltt-dev] Question about instruction pointer and address attributes

[Francis Giraldeau]

> > > I want to relate trace events to source code. For testing, I did a small 
> > > C program that does a file access. In the event kernel.syscall_entry 
> > > sys_access, I got the instruction pointer ip=0x7fa4fba26ee7. I dumped the 
> > > process memory map from /proc/$PID/maps, and this address doesn't fit in 
> > > the process memory space. It's somewhat close to libc addresses, that are 
> > > in the range of 0x7f6471f56000-0x7f64724fc000.
> > 
> > Make sure you cat the /proc/$PID/maps from the exact same process you
> > gather the trace from, because the addresses at which the libraries are
> > loaded and the stack is located are randomised between executions.
> > 

That was the problem. Inside the C program, I dumped the process memory
map on disk and it matches the events ip field. Once the random offset
removed from ip in syscall event, it matches exactly the address in libc
objdump. 

Thanks for this info! 

Francis