On Mon, Sep 30, 2024 at 02:36:03PM -0700, Andrii Nakryiko wrote: > On Sun, Sep 29, 2024 at 1:57 PM Jiri Olsa <jo...@kernel.org> wrote: > > > > This change allows the uprobe consumer to behave as session which > > means that 'handler' and 'ret_handler' callbacks are connected in > > a way that allows to: > > > > - control execution of 'ret_handler' from 'handler' callback > > - share data between 'handler' and 'ret_handler' callbacks > > > > The session concept fits to our common use case where we do filtering > > on entry uprobe and based on the result we decide to run the return > > uprobe (or not). > > > > It's also convenient to share the data between session callbacks. > > > > To achive this we are adding new return value the uprobe consumer > > can return from 'handler' callback: > > > > UPROBE_HANDLER_IGNORE > > - Ignore 'ret_handler' callback for this consumer. > > > > And store cookie and pass it to 'ret_handler' when consumer has both > > 'handler' and 'ret_handler' callbacks defined. > > > > We store shared data in the return_consumer object array as part of > > the return_instance object. This way the handle_uretprobe_chain can > > find related return_consumer and its shared data. > > > > We also store entry handler return value, for cases when there are > > multiple consumers on single uprobe and some of them are ignored and > > some of them not, in which case the return probe gets installed and > > we need to have a way to find out which consumer needs to be ignored. > > > > The tricky part is when consumer is registered 'after' the uprobe > > entry handler is hit. In such case this consumer's 'ret_handler' gets > > executed as well, but it won't have the proper data pointer set, > > so we can filter it out. > > > > Suggested-by: Oleg Nesterov <o...@redhat.com> > > Signed-off-by: Jiri Olsa <jo...@kernel.org> > > --- > > include/linux/uprobes.h | 21 +++++- > > kernel/events/uprobes.c | 148 +++++++++++++++++++++++++++++++--------- > > 2 files changed, 137 insertions(+), 32 deletions(-) > > > > LGTM, > > Acked-by: Andrii Nakryiko <and...@kernel.org> > > > Note also that I just resent the last patch from my patch set ([0]), > hopefully it will get applied, in which case you'd need to do a tiny > rebase. > > [0] > https://lore.kernel.org/linux-trace-kernel/20240930212246.1829395-1-and...@kernel.org/
the rebase is fine, but what I'm not clear about is that after yours and Oleg's changes get in, my kernel changes will depend on peter's perf/core, but bpf selftests changes will need bpf-next/master jirka
