On Thu, 19 Nov 2020 12:52:00 +0100 Petr Mladek <pmladek@xxxxxxxx> wrote: > > #ifdef CONFIG_LIVEPATCH > > -static inline void klp_arch_set_pc(struct pt_regs *regs, unsigned long ip) > > +static inline void klp_arch_set_pc(struct ftrace_regs *fregs, unsigned long ip) > > { > > + struct pt_regs *regs = ftrace_get_regs(fregs); > > Should we check for NULL pointer here? As mentioned in my last email. regs could have been NULL for the same reasons before this patch, and we didn't check it then. Why should we check it now? The ftrace_get_regs() only makes sure that a ftrace_ops that set FL_SAVE_REGS gets it, and those that did not, don't. But that's not entirely true either. If there's two callbacks to the same function, and one has FL_SAVE_REGS set, they both can have access to the regs (before and after this patch). It's just that the one that did not have FL_SAVE_REGS set, isn't guaranteed to have it. -- Steve > > > + > > regs->nip = ip; > > }