How does your test program issue the system call ? Is it directly with syscall() (see syscall(2) man page), or
does it call into libc ? Is your entire libc compiled with -fno-omit-frame-pointer ?
Indirectly, through libc/libstdc++. We use the default system libs (which I assume use -O, which in turn implies -fomit-frame-pointer).
As soon as one library in the chain to the system call is compiled without frame pointers, this is where the
stack walk stops. This is usually libc.
I see. Thanks for the information. Not sure we want to ship a custom libc unfortunately.
Related question: how feasible would adding the callstack-user context to userspace events be? If it is feasible, is such a feature planned?
Christophe