On Wed, May 13, 2020 at 10:03:13PM -0700, Andy Lutomirski wrote: > On Tue, May 5, 2020 at 7:16 AM Thomas Gleixner <[email protected]> wrote: > > > > For code simplicity split up the int3 handler into a kernel and user part > > which makes the code flow simpler to understand. > > > > Signed-off-by: Peter Zijlstra (Intel) <[email protected]> > > Signed-off-by: Thomas Gleixner <[email protected]> > > --- > > arch/x86/kernel/traps.c | 67 > > +++++++++++++++++++++++++++--------------------- > > 1 file changed, 39 insertions(+), 28 deletions(-) > > > > --- a/arch/x86/kernel/traps.c > > +++ b/arch/x86/kernel/traps.c > > @@ -564,6 +564,35 @@ DEFINE_IDTENTRY_ERRORCODE(exc_general_pr > > cond_local_irq_disable(regs); > > } > > > > +static bool do_int3(struct pt_regs *regs) > > +{ > > + int res; > > + > > +#ifdef CONFIG_KGDB_LOW_LEVEL_TRAP > > + if (kgdb_ll_trap(DIE_INT3, "int3", regs, 0, X86_TRAP_BP, > > + SIGTRAP) == NOTIFY_STOP) > > + return true; > > +#endif /* CONFIG_KGDB_LOW_LEVEL_TRAP */ > > + > > +#ifdef CONFIG_KPROBES > > + if (kprobe_int3_handler(regs)) > > + return true; > > +#endif > > + res = notify_die(DIE_INT3, "int3", regs, 0, X86_TRAP_BP, SIGTRAP); > > + > > + return res == NOTIFY_STOP; > > +} > > + > > +static void do_int3_user(struct pt_regs *regs) > > +{ > > + if (do_int3(regs)) > > + return; > > + > > + cond_local_irq_enable(regs); > > + do_trap(X86_TRAP_BP, SIGTRAP, "int3", regs, 0, 0, NULL); > > + cond_local_irq_disable(regs); > > +} > > + > > DEFINE_IDTENTRY_RAW(exc_int3) > > { > > /* > > @@ -581,37 +610,19 @@ DEFINE_IDTENTRY_RAW(exc_int3) > > * because the INT3 could have been hit in any context including > > * NMI. > > */ > > + if (user_mode(regs)) { > > idtentry_enter(regs); > > + instr_begin(); > > + do_int3_user(regs); > > + instr_end(); > > idtentry_exit(regs); > > + } else { > > + nmi_enter(); > > + instr_begin(); > > + do_int3(regs); > > I think you should be checking the return value here. Presumably this > should die() if it's not handled, since otherwise it will just > infinite loop.
Indeed. Thanks! > > + instr_end(); > > nmi_exit(); > > + } > > } > > > > #ifdef CONFIG_X86_64 > >
