> On Jun 28, 2018, at 5:18 PM, Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx> wrote: > >> On Thu, Jun 28, 2018 at 4:30 PM Andy Lutomirski <luto@xxxxxxxxxx> wrote: >> >> The idea is that, if someone screws up and sticks a number like >> 0xbaadf00d00045678 into their rseq abort_ip in a 32-bit x86 program >> (when they actually mean 0x00045678), we want to something consistent. > > I think the "something consistent" is perfectly fine with just "it won't work". > > Make it do > > if (rseq_cs->abort_ip != (unsigned long)rseq_cs->abort_ip) > return -EINVAL; > > at abort time. You sure? Because, unless I remember wrong, a 32-bit user program on a 64-bit kernel will actually work at least most of the time even if high bits are set. I’m okay with straight-up promising “will always work” or “will never work”, but “sometimes” is bad. > > Done. > > If it's a 32-bit kernel, the above will reject the thing, and if it's > a 64-bit kernel, it will be a no-op, but the abort won't work in a > 32-bit caller. > > Problem solved. > > Linus -- To unsubscribe from this list: send the line "unsubscribe linux-api" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
