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| 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/x86_64 | |
| parent | e5e3a0428968dcc1f9318ce1c941a918e99f8b84 (diff) | |
| download | linux-bb81a09e55eaf7e5f798468ab971469b6f66a259.tar.gz | |
[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/x86_64')
| -rw-r--r-- | arch/x86_64/kernel/nmi.c | 29 |
1 files changed, 28 insertions, 1 deletions
diff --git a/arch/x86_64/kernel/nmi.c b/arch/x86_64/kernel/nmi.c index 7af9cb3e2d99..27e95e7922c1 100644 --- a/arch/x86_64/kernel/nmi.c +++ b/arch/x86_64/kernel/nmi.c @@ -12,14 +12,15 @@ * Mikael Pettersson : PM converted to driver model. Disable/enable API. */ +#include <linux/nmi.h> #include <linux/mm.h> #include <linux/delay.h> #include <linux/interrupt.h> #include <linux/module.h> #include <linux/sysdev.h> -#include <linux/nmi.h> #include <linux/sysctl.h> #include <linux/kprobes.h> +#include <linux/cpumask.h> #include <asm/smp.h> #include <asm/nmi.h> @@ -41,6 +42,8 @@ int panic_on_unrecovered_nmi; static DEFINE_PER_CPU(unsigned, perfctr_nmi_owner); static DEFINE_PER_CPU(unsigned, evntsel_nmi_owner[2]); +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) */ @@ -782,6 +785,7 @@ int __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason) { int sum; int touched = 0; + int cpu = smp_processor_id(); struct nmi_watchdog_ctlblk *wd = &__get_cpu_var(nmi_watchdog_ctlblk); u64 dummy; int rc=0; @@ -799,6 +803,16 @@ int __kprobes 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); + } + #ifdef CONFIG_X86_MCE /* Could check oops_in_progress here too, but it's safer not too */ @@ -931,6 +945,19 @@ 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); |