On Mon, May 01, 2017 at 10:36:59AM -0700, Kees Cook wrote: > >> +#ifdef CONFIG_FAST_REFCOUNT > >> +static DEFINE_RATELIMIT_STATE(refcount_ratelimit, 15 * HZ, 3); > >> + > >> +void refcount_error_report(struct pt_regs *regs, const char *kind) > >> +{ > >> + do_send_sig_info(SIGKILL, SEND_SIG_FORCED, current, true); > >> + > >> + if (!__ratelimit(&refcount_ratelimit)) > >> + return; > >> + > >> + pr_emerg("%s detected in: %s:%d, uid/euid: %u/%u\n", > >> + kind ? kind : "refcount error", > >> + current->comm, task_pid_nr(current), > >> + from_kuid_munged(&init_user_ns, current_uid()), > >> + from_kuid_munged(&init_user_ns, current_euid())); > >> + print_symbol(KERN_EMERG "refcount error occurred at: %s\n", > >> + instruction_pointer(regs)); > >> + preempt_disable(); > >> + show_regs(regs); > >> + preempt_enable(); > >> +} > > > > Why is preemption disabled before calling show_regs()? > > I thought it was to avoid interleaving show_regs() output (I can't > think of a way regs would be externally modified). This code is running from interrupt context, so preemption shouldn't be an issue unless I'm missing something. -- Josh