On Fri, Feb 15, 2019 at 3:06 PM Davide Caratti <dcara...@redhat.com> wrote: > > currently, the kernel checks for bad values of the control action in > tcf_action_init_1(), after a successful call to the action's init() > function. This causes three bad behaviors:
Yeah, I have been complaining about this for a long time, although slightly differently. The problem here is the lack of "copy" in RCU mechanism, which makes it nearly impossible to rollback to the previous state of an action on failure path of an update, which also makes RCU readers reading a partially updated action too. Before I fix the "copy" part, your fixes make sense to me. There might be some other way to expose the action-specific tcfa_action opcode, but it might not be better than yours. BTW, please fold these bad behaviors into each appropriate patch, and keep the cover letter as an overview of the whole patchset rather than showing any details. [...] > all these three problems can be fixed if we validate the control action > in the init() function, in the same way as we are already doing for all > the other parameters. > > - patch 1 is a temporary fix for problem 2), but it's reverted at the > end of the series Please drop patch 1, it is very unlikely only patch 1 will be backported, I think the whole patchset should be, therefore we have no reason to carry a temporary fix here. Thanks.
