On Thu, Aug 30, 2018 at 1:04 PM Guillaume Nault <g.nault@xxxxxxxxxxxx> wrote: > > On Wed, Aug 29, 2018 at 04:03:26PM +0200, Arnd Bergmann wrote: > > Support for handling the PPPOEIOCSFWD ioctl in compat mode was added in > > linux-2.5.69 along with hundreds of other commands, but was always broken > > sincen only the structure is compatible, but the command number is not, > > due to the size being sizeof(size_t), or at first sizeof(sizeof((struct > > sockaddr_pppox)), which is different on 64-bit architectures. > > > And the implementation was broken until 2016 (see 29e73269aa4d ("pppoe: > fix reference counting in PPPoE proxy")), and nobody ever noticed. I > should probably have removed this ioctl entirely instead of fixing it. > Clearly, it has never been used. > > If you think it's worth fixing (as opposed to dropping this ioctl or > its compat mode), then, > Acked-by: Guillaume Nault <g.nault@xxxxxxxxxxxx> I don't care much, but fixing it seems seems easier than coming up with a convincing rationale for dropping. I'll update the changelog text to include your additional background information though, unless someone else prefers to have it dropped. Arnd