On Tue, 28 Jan 2025 11:46:25 -0500 Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> wrote: > I'm trying to wrap my head around what you are trying to achieve here. > > So AFAIU you are aiming to store the relative offset from kernel _text > and module base text address into the traced events rather than the > actual address. > > Based on Masami's cover letter, this appears to be done to make sure > users can get to this base+offset information even if they cannot read > kallsyms. > > Why make the tracing fast path more complex for a simple matter of > accessing this base address information ? > > All you need to have to convert from kernel address to base + offset is: > > - The kernel _text base address, > - Each loaded module text base address, > - Unloaded modules events to prune this information. > > What is wrong with simply exporting this base address information in the > trace buffers rather than rely on kallsyms, and deal with the conversion > to module name / base+offset at post-processing ? Hmm, we could probably get away with that too. I think we were focused on kallsyms, where we wanted a way to not have to distinguish between current boot info and previous boot info. But when we started pulling in the module info, it may be possible to do a post processing. I have said in the past that I wanted module information in the persistent memory. By doing that this may not be needed. I'll look into it. -- Steve
