Kees Cook <keescook@xxxxxxxxxxxx> writes: > On Tue, Oct 01, 2019 at 01:36:32PM -0500, Eric W. Biederman wrote: >> >> This system call has been deprecated almost since it was introduced, and >> in a survey of the linux distributions I can no longer find any of them >> that enable CONFIG_SYSCTL_SYSCALL. The only indication that I can find >> that anyone might care is that a few of the defconfigs in the kernel >> enable CONFIG_SYSCTL_SYSCALL. However this appears in only 31 of 414 >> defconfigs in the kernel, so I suspect this symbols presence is simply >> because it is harmless to include rather than because it is necessary. >> >> As there appear to be no users of the sysctl system call, remove the >> code. As this removes one of the few uses of the internal kernel mount >> of proc I hope this allows for even more simplifications of the proc >> filesystem. > > I'm for it. :) I tripped over this being deprecated over a decade ago. :P > > I think you can actually take this further and remove (or at least > empty) the uapi/linux/sysctl.h file too. I copied everyone who had put this into a defconfig and I will wait a little more to see if anyone screams. I think it is a safe guess that several of the affected configurations are dead (or at least unmaintained) as I received 17 bounces when copying everyone. I would make it a followup that removes uapi/linux/sysctl.h. I don't see anything in it that isn't about the sysctl system call. I will keep it a separate patch as I can imagine something silly that needs the header file to compile. A separate patch would make a revert easier if we find something like that. Eric
