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authorNicholas Piggin <npiggin@gmail.com>2018-01-17 13:47:22 +0100
committerMichael Ellerman <mpe@ellerman.id.au>2018-01-18 05:43:43 +0100
commit47712a921bb781caf69fca9eae43be19968816cb (patch)
tree823db9b05645ce56f677a8c5a7276c7d58ca5f3a /arch/powerpc/kernel/watchdog.c
parentpowerpc/64s: Relax PACA address limitations (diff)
downloadlinux-47712a921bb781caf69fca9eae43be19968816cb.tar.xz
linux-47712a921bb781caf69fca9eae43be19968816cb.zip
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 <npiggin@gmail.com> Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to '')
-rw-r--r--arch/powerpc/kernel/watchdog.c22
1 files changed, 0 insertions, 22 deletions
diff --git a/arch/powerpc/kernel/watchdog.c b/arch/powerpc/kernel/watchdog.c
index 87da80ccced1..3963baaba92d 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);
-}