On Fri, Jun 29, 2018 at 9:07 AM Mathieu Desnoyers <mathieu.desnoyers@xxxxxxxxxxxx> wrote: > > This code is not invoked from syscalls, but rather on return from > interrupt/trap after a preemption. But when we register the rseq, we could easily check that the top bits of the IP is clear, no? Sure, user space can change it after the fact, but at that point it's literally "user space is being intentionally stupid". The real worry is that 32-bit compat code never initializes those bits at all, no? 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