Subject: + nmi-provide-the-option-to-issue-an-nmi-back-trace-to-every-cpu-but-current.patch added to -mm tree
To: atomlin@xxxxxxxxxx,davem@xxxxxxxxxxxxx,dzickus@xxxxxxxxxx,mguzik@xxxxxxxxxx,oleg@xxxxxxxxxx
From: akpm@xxxxxxxxxxxxxxxxxxxx
Date: Wed, 23 Apr 2014 14:14:12 -0700
The patch titled
Subject: nmi: provide the option to issue an NMI back trace to every cpu but current
has been added to the -mm tree. Its filename is
nmi-provide-the-option-to-issue-an-nmi-back-trace-to-every-cpu-but-current.patch
This patch should soon appear at
http://ozlabs.org/~akpm/mmots/broken-out/nmi-provide-the-option-to-issue-an-nmi-back-trace-to-every-cpu-but-current.patch
and later at
http://ozlabs.org/~akpm/mmotm/broken-out/nmi-provide-the-option-to-issue-an-nmi-back-trace-to-every-cpu-but-current.patch
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------------------------------------------------------
From: Aaron Tomlin <atomlin@xxxxxxxxxx>
Subject: nmi: provide the option to issue an NMI back trace to every cpu but current
Sometimes it is preferred not to use the trigger_all_cpu_backtrace()
routine when one wants to avoid capturing a back trace for current. For
instance if one was previously captured recently.
This patch provides a new routine namely
trigger_allbutself_cpu_backtrace() which offers the flexibility to issue
an NMI to every cpu but current and capture a back trace accordingly.
Patch x86 and sparc to support new routine.
[dzickus@xxxxxxxxxx: add stub in #else clause]
[dzickus@xxxxxxxxxx: don't print message in single processor case, wrap with get/put_cpu based on Oleg's suggestion]
Signed-off-by: Aaron Tomlin <atomlin@xxxxxxxxxx>
Signed-off-by: Don Zickus <dzickus@xxxxxxxxxx>
Acked-by: David S. Miller <davem@xxxxxxxxxxxxx>
Cc: Mateusz Guzik <mguzik@xxxxxxxxxx>
Cc: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/sparc/include/asm/irq_64.h | 2 +-
arch/sparc/kernel/process_64.c | 14 +++++++++-----
arch/x86/include/asm/irq.h | 2 +-
arch/x86/kernel/apic/hw_nmi.c | 17 +++++++++++++----
include/linux/nmi.h | 11 ++++++++++-
5 files changed, 34 insertions(+), 12 deletions(-)
diff -puN arch/sparc/include/asm/irq_64.h~nmi-provide-the-option-to-issue-an-nmi-back-trace-to-every-cpu-but-current arch/sparc/include/asm/irq_64.h
--- a/arch/sparc/include/asm/irq_64.h~nmi-provide-the-option-to-issue-an-nmi-back-trace-to-every-cpu-but-current
+++ a/arch/sparc/include/asm/irq_64.h
@@ -89,7 +89,7 @@ static inline unsigned long get_softint(
return retval;
}
-void arch_trigger_all_cpu_backtrace(void);
+void arch_trigger_all_cpu_backtrace(bool);
#define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
extern void *hardirq_stack[NR_CPUS];
diff -puN arch/sparc/kernel/process_64.c~nmi-provide-the-option-to-issue-an-nmi-back-trace-to-every-cpu-but-current arch/sparc/kernel/process_64.c
--- a/arch/sparc/kernel/process_64.c~nmi-provide-the-option-to-issue-an-nmi-back-trace-to-every-cpu-but-current
+++ a/arch/sparc/kernel/process_64.c
@@ -239,7 +239,7 @@ static void __global_reg_poll(struct glo
}
}
-void arch_trigger_all_cpu_backtrace(void)
+void arch_trigger_all_cpu_backtrace(bool include_self)
{
struct thread_info *tp = current_thread_info();
struct pt_regs *regs = get_irq_regs();
@@ -251,15 +251,19 @@ void arch_trigger_all_cpu_backtrace(void
spin_lock_irqsave(&global_cpu_snapshot_lock, flags);
- memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
-
this_cpu = raw_smp_processor_id();
- __global_reg_self(tp, regs, this_cpu);
+ memset(global_cpu_snapshot, 0, sizeof(global_cpu_snapshot));
+
+ if (include_self)
+ __global_reg_self(tp, regs, this_cpu);
smp_fetch_global_regs();
for_each_online_cpu(cpu) {
+ if (!include_self && cpu == this_cpu)
+ continue;
+
struct global_reg_snapshot *gp = &global_cpu_snapshot[cpu].reg;
__global_reg_poll(gp);
@@ -292,7 +296,7 @@ void arch_trigger_all_cpu_backtrace(void
static void sysrq_handle_globreg(int key)
{
- arch_trigger_all_cpu_backtrace();
+ arch_trigger_all_cpu_backtrace(true);
}
static struct sysrq_key_op sparc_globalreg_op = {
diff -puN arch/x86/include/asm/irq.h~nmi-provide-the-option-to-issue-an-nmi-back-trace-to-every-cpu-but-current arch/x86/include/asm/irq.h
--- a/arch/x86/include/asm/irq.h~nmi-provide-the-option-to-issue-an-nmi-back-trace-to-every-cpu-but-current
+++ a/arch/x86/include/asm/irq.h
@@ -43,7 +43,7 @@ extern int vector_used_by_percpu_irq(uns
extern void init_ISA_irqs(void);
#ifdef CONFIG_X86_LOCAL_APIC
-void arch_trigger_all_cpu_backtrace(void);
+void arch_trigger_all_cpu_backtrace(bool);
#define arch_trigger_all_cpu_backtrace arch_trigger_all_cpu_backtrace
#endif
diff -puN arch/x86/kernel/apic/hw_nmi.c~nmi-provide-the-option-to-issue-an-nmi-back-trace-to-every-cpu-but-current arch/x86/kernel/apic/hw_nmi.c
--- a/arch/x86/kernel/apic/hw_nmi.c~nmi-provide-the-option-to-issue-an-nmi-back-trace-to-every-cpu-but-current
+++ a/arch/x86/kernel/apic/hw_nmi.c
@@ -33,31 +33,40 @@ static DECLARE_BITMAP(backtrace_mask, NR
/* "in progress" flag of arch_trigger_all_cpu_backtrace */
static unsigned long backtrace_flag;
-void arch_trigger_all_cpu_backtrace(void)
+void arch_trigger_all_cpu_backtrace(bool include_self)
{
int i;
+ int cpu = get_cpu();
- if (test_and_set_bit(0, &backtrace_flag))
+ if (test_and_set_bit(0, &backtrace_flag)) {
/*
* If there is already a trigger_all_cpu_backtrace() in progress
* (backtrace_flag == 1), don't output double cpu dump infos.
*/
+ put_cpu();
return;
+ }
cpumask_copy(to_cpumask(backtrace_mask), cpu_online_mask);
+ if (!include_self)
+ cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask));
- printk(KERN_INFO "sending NMI to all CPUs:\n");
- apic->send_IPI_all(NMI_VECTOR);
+ if (!cpumask_empty(to_cpumask(backtrace_mask))) {
+ pr_info("sending NMI to %s CPUs:\n", (include_self ? "all" : "other"));
+ apic->send_IPI_mask(to_cpumask(backtrace_mask), NMI_VECTOR);
+ }
/* Wait for up to 10 seconds for all CPUs to do the backtrace */
for (i = 0; i < 10 * 1000; i++) {
if (cpumask_empty(to_cpumask(backtrace_mask)))
break;
mdelay(1);
+ touch_softlockup_watchdog();
}
clear_bit(0, &backtrace_flag);
smp_mb__after_clear_bit();
+ put_cpu();
}
static int __kprobes
diff -puN include/linux/nmi.h~nmi-provide-the-option-to-issue-an-nmi-back-trace-to-every-cpu-but-current include/linux/nmi.h
--- a/include/linux/nmi.h~nmi-provide-the-option-to-issue-an-nmi-back-trace-to-every-cpu-but-current
+++ a/include/linux/nmi.h
@@ -32,15 +32,24 @@ static inline void touch_nmi_watchdog(vo
#ifdef arch_trigger_all_cpu_backtrace
static inline bool trigger_all_cpu_backtrace(void)
{
- arch_trigger_all_cpu_backtrace();
+ arch_trigger_all_cpu_backtrace(true);
return true;
}
+static inline bool trigger_allbutself_cpu_backtrace(void)
+{
+ arch_trigger_all_cpu_backtrace(false);
+ return true;
+}
#else
static inline bool trigger_all_cpu_backtrace(void)
{
return false;
}
+static inline bool trigger_allbutself_cpu_backtrace(void)
+{
+ return false;
+}
#endif
#ifdef CONFIG_LOCKUP_DETECTOR
_
Patches currently in -mm which might be from atomlin@xxxxxxxxxx are
nmi-provide-the-option-to-issue-an-nmi-back-trace-to-every-cpu-but-current.patch
kernel-watchdogc-print-traces-for-all-cpus-on-lockup-detection.patch
kernel-watchdogc-print-traces-for-all-cpus-on-lockup-detection-fix.patch
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