From 80e4d70b06863e0104e5a0dc78aa3710297fbd4b Mon Sep 17 00:00:00 2001 From: Nicholas Piggin Date: Fri, 29 Sep 2017 13:29:39 +1000 Subject: [PATCH] powerpc/watchdog: Do not trigger SMP crash from touch_nmi_watchdog In xmon, touch_nmi_watchdog() is not expected to be checking that other CPUs have not touched the watchdog, so the code will just call touch_nmi_watchdog() once before re-enabling hard interrupts. Just update our CPU's state, and ignore apparently stuck SMP threads. Arguably touch_nmi_watchdog should check for SMP lockups, and callers should be fixed, but that's not trivial for the input code of xmon. Signed-off-by: Nicholas Piggin Signed-off-by: Michael Ellerman --- arch/powerpc/kernel/watchdog.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c index 920e61c79f47..1fb9379dc683 100644 --- a/arch/powerpc/kernel/watchdog.c +++ b/arch/powerpc/kernel/watchdog.c @@ -277,9 +277,12 @@ void arch_touch_nmi_watchdog(void) { unsigned long ticks = tb_ticks_per_usec * wd_timer_period_ms * 1000; int cpu = smp_processor_id(); + u64 tb = get_tb(); - if (get_tb() - per_cpu(wd_timer_tb, cpu) >= ticks) - watchdog_timer_interrupt(cpu); + if (tb - per_cpu(wd_timer_tb, cpu) >= ticks) { + per_cpu(wd_timer_tb, cpu) = tb; + wd_smp_clear_cpu_pending(cpu, tb); + } } EXPORT_SYMBOL(arch_touch_nmi_watchdog); -- 2.11.0