On 2019-04-12 19:17:59 [+0200], Borislav Petkov wrote: > > @@ -327,7 +327,19 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) > > if (ret) > > goto err_out; > > envp = &env; > > + } else { > > I've added here: I would suggest to add it in the last patch once we have the complete fast path. The other one extended (in case you want to add a comment there, too). > + /* /** > + * Attempt to restore the FPU registers directly from user > + * memory. For that to succeed, the user accesses cannot cause I would say "user access" because it is always a single instruction. > + * page faults. If they do, fall back to the slow path below, > + * going through the kernel buffer. "with the enabled page fault handler". > + */ > > so that it is clear what's happening. > > This function is doing gazillion things again ;-\ It is the old code with disabled page fault handler. But I understand. Sebastian