On Tue, Aug 20, 2019 at 09:14:29PM -0400, Steven Rostedt wrote: > On Tue, 20 Aug 2019 12:58:49 +0200 > Christophe Leroy <[email protected]> wrote: > > > >> index 1077366f496b..6c22e8a6f9de 100644 > > >> --- a/lib/bug.c > > >> +++ b/lib/bug.c > > >> @@ -181,6 +181,15 @@ enum bug_trap_type report_bug(unsigned long > > >> bugaddr, struct pt_regs *regs) > > >> } > > >> } > > >> > > >> + /* > > >> + * BUG() and WARN_ON() families don't print a custom debug > > >> message > > >> + * before triggering the exception handler, so we must add the > > >> + * "cut here" line now. WARN() issues its own "cut here" before > > >> the > > >> + * extra debugging message it writes before triggering the > > >> handler. > > >> + */ > > >> + if ((bug->flags & BUGFLAG_PRINTK) == 0) > > >> + printk(KERN_DEFAULT CUT_HERE); > > > > > > I'm not loving that BUGFLAG_PRINTK name, BUGFLAG_CUT_HERE makes more > > > sense to me. > > > > > > > Actually it would be BUGFLAG_NO_CUT_HERE then, otherwise all arches not > > using the generic macros will have to add the flag to get the "cut here" > > line. > > > > Perhaps they all should be audited to see if they don't have the same > problem?
As far as I could tell, all the other combinations end up either using the slow path bug helpers or the common exception handler. warn-with-a-fmt-string is the only case that does the "early cut here". -- Kees Cook
