Messages in this thread Patch in this message | | | From | Jason Wessel <> | Subject | [PATCH 1/2] kgdb, x86: Avoid invoking kgdb_nmicallback twice per NMI | Date | Mon, 6 Oct 2008 14:14:14 -0500 |
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From: Jan Kiszka <jan.kiszka@siemens.com>
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 <jan.kiszka@siemens.com> Signed-off-by: Jason Wessel <jason.wessel@windriver.com> --- arch/x86/kernel/kgdb.c | 7 +------ 1 files changed, 1 insertions(+), 6 deletions(-)
diff --git a/arch/x86/kernel/kgdb.c b/arch/x86/kernel/kgdb.c index 8282a21..10435a1 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: -- 1.6.0.2
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