From: Jan Kiszka Date: Mon, 6 Oct 2008 18:50:59 +0000 (-0500) Subject: kgdb, x86: Avoid invoking kgdb_nmicallback twice per NMI X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=e85ceae9102f6e3c1d707e7ac88fa48d252e9cfa;p=GitHub%2FLineageOS%2Fandroid_kernel_motorola_exynos9610.git kgdb, x86: Avoid invoking kgdb_nmicallback twice per NMI Stress-testing KVM's latest NMI support with kgdbts inside an SMP guest, I came across spurious unhandled NMIs while running the singlestep test. Looking closer at the code path each NMI takes when KGDB is enabled, I noticed that kgdb_nmicallback is called twice per event: One time via DIE_NMI_IPI notification, the second time on DIE_NMI. Removing the first invocation cures the unhandled NMIs here. Signed-off-by: Jan Kiszka Signed-off-by: Jason Wessel --- diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 8282a2139681..10435a120d22 100644 --- a/arch/x86/kernel/kgdb.c +++ b/arch/x86/kernel/kgdb.c @@ -455,12 +455,7 @@ static int __kgdb_notify(struct die_args *args, unsigned long cmd) return NOTIFY_DONE; case DIE_NMI_IPI: - if (atomic_read(&kgdb_active) != -1) { - /* KGDB CPU roundup */ - kgdb_nmicallback(raw_smp_processor_id(), regs); - was_in_debug_nmi[raw_smp_processor_id()] = 1; - touch_nmi_watchdog(); - } + /* Just ignore, we will handle the roundup on DIE_NMI. */ return NOTIFY_DONE; case DIE_NMIUNKNOWN: