On Mon, 19 Feb 2018 11:53:50 -0500 Waiman Long <longman@xxxxxxxxxx> wrote: > Even with clamped sysctl parameters, it is still not that straight > forward to figure out the exact range of those parameters. One may > try to write extreme parameter values to see if they get clamped. > To make it easier, a warning with the expected range will now be > printed in the kernel ring buffer when a clamped sysctl parameter > receives an out of range value. This assumes that do_proc_dointvec_minmax_conv() and do_proc_douintvec_minmax_conv() are only ever called by privileged userspace. Because we mustn't give unprivileged applications a way to spam the kernel logs. That's presumably true in the case of the caller you just added, but I don't see what we can do to guarantee this in the future, so perhaps we should add some permission check to the pr_warn()?