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authorAaron Tomlin <atomlin@redhat.com>2014-06-23 13:22:05 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-06-23 16:47:44 -0700
commitf3aca3d09525f87731ba6b892c9b010570bc54b4 (patch)
tree80c80be186f7bac74cb548444562ae6890938d83
parent88e15ce402c58f41037752da092683e90826742a (diff)
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@redhat.com: add stub in #else clause] [dzickus@redhat.com: don't print message in single processor case, wrap with get/put_cpu based on Oleg's suggestion] [sfr@canb.auug.org.au: undo C99ism] Signed-off-by: Aaron Tomlin <atomlin@redhat.com> Signed-off-by: Don Zickus <dzickus@redhat.com> Acked-by: David S. Miller <davem@davemloft.net> Cc: Mateusz Guzik <mguzik@redhat.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Stephen Rothwell <sfr@canb.auug.org.au> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--arch/sparc/include/asm/irq_64.h2
-rw-r--r--arch/sparc/kernel/process_64.c18
-rw-r--r--arch/x86/include/asm/irq.h2
-rw-r--r--arch/x86/kernel/apic/hw_nmi.c18
-rw-r--r--include/linux/nmi.h11
5 files changed, 38 insertions, 13 deletions
diff --git a/arch/sparc/include/asm/irq_64.h b/arch/sparc/include/asm/irq_64.h
index 375cffcf7dbd..91d219381306 100644
--- a/arch/sparc/include/asm/irq_64.h
+++ b/arch/sparc/include/asm/irq_64.h
@@ -89,7 +89,7 @@ static inline unsigned long get_softint(void)
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 --git a/arch/sparc/kernel/process_64.c b/arch/sparc/kernel/process_64.c
index b2988f25e230..027e09986194 100644
--- a/arch/sparc/kernel/process_64.c
+++ b/arch/sparc/kernel/process_64.c
@@ -239,7 +239,7 @@ static void __global_reg_poll(struct global_reg_snapshot *gp)
}
}
-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();
@@ -251,16 +251,22 @@ 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) {
- struct global_reg_snapshot *gp = &global_cpu_snapshot[cpu].reg;
+ struct global_reg_snapshot *gp;
+
+ if (!include_self && cpu == this_cpu)
+ continue;
+
+ gp = &global_cpu_snapshot[cpu].reg;
__global_reg_poll(gp);
@@ -292,7 +298,7 @@ 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 --git a/arch/x86/include/asm/irq.h b/arch/x86/include/asm/irq.h
index cb6cfcd034cf..a80cbb88ea91 100644
--- a/arch/x86/include/asm/irq.h
+++ b/arch/x86/include/asm/irq.h
@@ -43,7 +43,7 @@ extern int vector_used_by_percpu_irq(unsigned int vector);
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 --git a/arch/x86/kernel/apic/hw_nmi.c b/arch/x86/kernel/apic/hw_nmi.c
index c3fcb5de5083..6a1e71bde323 100644
--- a/arch/x86/kernel/apic/hw_nmi.c
+++ b/arch/x86/kernel/apic/hw_nmi.c
@@ -33,31 +33,41 @@ static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
/* "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_atomic();
+ put_cpu();
}
static int
diff --git a/include/linux/nmi.h b/include/linux/nmi.h
index 6a45fb583ff1..a17ab6398d7c 100644
--- a/include/linux/nmi.h
+++ b/include/linux/nmi.h
@@ -32,15 +32,24 @@ static inline void touch_nmi_watchdog(void)
#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