== Comment: #0 - Application Cdeadmin <email address hidden> - 2018-04-03 05:20:56 ==
== Comment: #1 - Application Cdeadmin <> - 2018-04-05 01:30:56 ==
------- Comment From pridhiviraj 2018-04-05 01:30:25 EDT -------
The disto needs 47712a921bb781caf69fca9eae43be19968816cb this level of commits need to be backported as suggested by Nick piggin.
== Comment: #2 - PAWAN K. SINGH <> - 2018-04-06 03:35:49 ==
which is ----
>>>
From 47712a921bb781caf69fca9eae43be19968816cb Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <email address hidden>
Date: Wed, 17 Jan 2018 22:47:22 +1000
Subject: [PATCH] powerpc/watchdog: remove arch_trigger_cpumask_backtrace
The powerpc NMI IPIs may not be recoverable if they are taken in
some sections of code, and also there have been and still are issues
with taking NMIs (in KVM guest code, in firmware, etc) which makes them
a bit dangerous to use.
Generic code like softlockup detector and rcu stall detectors really
hammer on trigger_*_backtrace, which has lead to further problems
because we've implemented it with the NMI.
So stop providing NMI backtraces for now. Importantly, the powerpc code
uses NMI IPIs in crash/debug, and the SMP hardlockup watchdog. So if the
softlockup and rcu hang detection traces are not being printed because
the CPU is stuck with interrupts off, then the hard lockup watchdog
should get it with the NMI IPI.
Fixes: 2104180a5369 ("powerpc/64s: implement arch-specific hardlockup watchdog")
Signed-off-by: Nicholas Piggin <email address hidden>
Signed-off-by: Michael Ellerman <email address hidden>
---
arch/powerpc/include/asm/nmi.h | 4 ----
arch/powerpc/kernel/watchdog.c | 22 ----------------------
2 files changed, 26 deletions(-)
diff --git a/arch/powerpc/include/asm/nmi.h b/arch/powerpc/include/asm/nmi.h
index e97f586..9c80939 100644
--- a/arch/powerpc/include/asm/nmi.h
+++ b/arch/powerpc/include/asm/nmi.h
@@ -4,10 +4,6 @@
#ifdef CONFIG_PPC_WATCHDOG
extern void arch_touch_nmi_watchdog(void);
-extern void arch_trigger_cpumask_backtrace(const cpumask_t *mask,
- bool exclude_self);
-#define arch_trigger_cpumask_backtrace arch_trigger_cpumask_backtrace
-
#else
static inline void arch_touch_nmi_watchdog(void) {}
#endif
diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c
index 87da80c..3963baa 100644
--- a/arch/powerpc/kernel/watchdog.c
+++ b/arch/powerpc/kernel/watchdog.c
@@ -393,25 +393,3 @@ int __init watchdog_nmi_probe(void)
}
return 0;
}
-
-static void handle_backtrace_ipi(struct pt_regs *regs)
-{
- nmi_cpu_backtrace(regs);
-}
-
-static void raise_backtrace_ipi(cpumask_t *mask)
-{
- unsigned int cpu;
-
- for_each_cpu(cpu, mask) {
- if (cpu == smp_processor_id())
- handle_backtrace_ipi(NULL);
- else
- smp_send_nmi_ipi(cpu, handle_backtrace_ipi, 1000000);
- }
-}
-
-void arch_trigger_cpumask_backtrace(const cpumask_t *mask, bool exclude_self)
-{
- nmi_trigger_cpumask_backtrace(mask, exclude_self, raise_backtrace_ipi);
-}
--
2.7.4
>>>
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