Re: [PATCH v6 3/4] net: dropreason: use new __print_sym() in tracing

On Tue, 2026-09-22 at 07:35 -0700, Adrián Moreno wrote:

quoted

IIUC, this change only affects the printing and doesn't affect debugging
tools like retis that attempt to surface the drop reasons.  But, maybe
Adrian and Antoine (CCed) may want to have a glance as well.

I don't think this will affect retis in a bad way. We collect the list
of drop reasons by inspecting the BTF enums. It generally works but we
need to keep track of new subsystems enums being added

Right, that wouldn't really change.

so a dynamically-generated full-list of drop reasons is interesting.

IIUC, the only way for userspace to read this list is by looking at the
event format and parse the printf line, right? Any ideas to make this
more machine-friendly?

It's intended to be machine friendly "enough", trace-cmd/perf (via
libtraceevent or so I think?) parse and use this? But it's also only
available when tracing is enabled.

I think if you really wanted to have a full list dynamically exposed at
runtime across all kernels, then perhaps dropmonitor or some other
netlink interface could expose it? Or maybe another debugfs/sysfs file?
I don't know what you need it for, but I think it's out of scope for
this patchset, and could even be done without it?

johannes