diff options
| author | Andrew Morton <akpm@osdl.org> | 2006-12-07 02:14:01 +0100 |
|---|---|---|
| committer | Andi Kleen <andi@basil.nowhere.org> | 2006-12-07 02:14:01 +0100 |
| commit | bb81a09e55eaf7e5f798468ab971469b6f66a259 (patch) | |
| tree | cf1ed6b0ad75137361228955535044fd4630a57b /arch/i386/kernel/nmi.c | |
| parent | e5e3a0428968dcc1f9318ce1c941a918e99f8b84 (diff) | |
[PATCH] x86: all cpu backtrace
When a spinlock lockup occurs, arrange for the NMI code to emit an all-cpu
backtrace, so we get to see which CPU is holding the lock, and where.
Cc: Andi Kleen <ak@muc.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Badari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Andi Kleen <ak@suse.de>
Diffstat (limited to 'arch/i386/kernel/nmi.c')
| -rw-r--r-- | arch/i386/kernel/nmi.c | 26 |
1 files changed, 26 insertions, 0 deletions
diff --git a/arch/i386/kernel/nmi.c b/arch/i386/kernel/nmi.c index eaafe233a5d..171194ccb7b 100644 --- a/arch/i386/kernel/nmi.c +++ b/arch/i386/kernel/nmi.c @@ -22,6 +22,7 @@ #include <linux/percpu.h> #include <linux/dmi.h> #include <linux/kprobes.h> +#include <linux/cpumask.h> #include <asm/smp.h> #include <asm/nmi.h> @@ -42,6 +43,8 @@ int nmi_watchdog_enabled; static DEFINE_PER_CPU(unsigned long, perfctr_nmi_owner); static DEFINE_PER_CPU(unsigned long, evntsel_nmi_owner[3]); +static cpumask_t backtrace_mask = CPU_MASK_NONE; + /* this number is calculated from Intel's MSR_P4_CRU_ESCR5 register and it's * offset from MSR_P4_BSU_ESCR0. It will be the max for all platforms (for now) */ @@ -907,6 +910,16 @@ __kprobes int nmi_watchdog_tick(struct pt_regs * regs, unsigned reason) touched = 1; } + if (cpu_isset(cpu, backtrace_mask)) { + static DEFINE_SPINLOCK(lock); /* Serialise the printks */ + + spin_lock(&lock); + printk("NMI backtrace for cpu %d\n", cpu); + dump_stack(); + spin_unlock(&lock); + cpu_clear(cpu, backtrace_mask); + } + sum = per_cpu(irq_stat, cpu).apic_timer_irqs; /* if the apic timer isn't firing, this cpu isn't doing much */ @@ -1033,6 +1046,19 @@ int proc_nmi_enabled(struct ctl_table *table, int write, struct file *file, #endif +void __trigger_all_cpu_backtrace(void) +{ + int i; + + backtrace_mask = cpu_online_map; + /* Wait for up to 10 seconds for all CPUs to do the backtrace */ + for (i = 0; i < 10 * 1000; i++) { + if (cpus_empty(backtrace_mask)) + break; + mdelay(1); + } +} + EXPORT_SYMBOL(nmi_active); EXPORT_SYMBOL(nmi_watchdog); EXPORT_SYMBOL(avail_to_resrv_perfctr_nmi); |