On Thu, Aug 20, 2020 at 6:53 AM Peter Zijlstra <pet...@infradead.org> wrote: > > > Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> > --- > arch/x86/kernel/traps.c | 24 ++++++++++++------------ > 1 file changed, 12 insertions(+), 12 deletions(-) > > --- a/arch/x86/kernel/traps.c > +++ b/arch/x86/kernel/traps.c > @@ -820,18 +820,6 @@ static void handle_debug(struct pt_regs > goto out; > } > > - if (WARN_ON_ONCE((dr6 & DR_STEP) && !user_mode(regs))) { > - /* > - * Historical junk that used to handle SYSENTER > single-stepping. > - * This should be unreachable now. If we survive for a while > - * without anyone hitting this warning, we'll turn this into > - * an oops. > - */ > - tsk->thread.debugreg6 &= ~DR_STEP; > - set_tsk_thread_flag(tsk, TIF_SINGLESTEP); > - regs->flags &= ~X86_EFLAGS_TF; > - } > - > si_code = get_si_code(tsk->thread.debugreg6); > if (tsk->thread.debugreg6 & (DR_STEP | DR_TRAP_BITS) || user_icebp) > send_sigtrap(regs, 0, si_code); > @@ -874,6 +862,18 @@ static __always_inline void exc_debug_ke > if (kprobe_debug_handler(regs)) > goto out; > > + if (WARN_ON_ONCE(dr6 & DR_STEP)) { > + /* > + * Historical junk that used to handle SYSENTER > single-stepping. > + * This should be unreachable now. If we survive for a while > + * without anyone hitting this warning, we'll turn this into > + * an oops. > + */ > + dr6 &= ~DR_STEP; > + set_thread_flag(TIF_SINGLESTEP); > + regs->flags &= ~X86_EFLAGS_TF; > + } > + > handle_debug(regs, dr6, false); > > out:
Can this be removed or changed to a BUG()? The warning has been there since 2016 and nobody has apparently complained about it. -- Brian Gerst