From: Hiroshi Shimamoto <h-shimamoto@xxxxxxxxxxxxx> In nmi_show_all_regs(), set nmi_show_regs for all cpus but NMI never come to itself when nmi_watchdog is disabled. It means the kernel hangs up when sysrq+l is issued. Call irq_show_regs_callback() itself before calling smp_send_nmi_allbutself(). Signed-off-by: Hiroshi Shimamoto <h-shimamoto@xxxxxxxxxxxxx> --- Steven, this is a fix for what you pointed. http://lkml.org/lkml/2008/4/28/455 arch/x86/kernel/nmi_32.c | 51 ++++++++++++++++++++++++++++------------------ arch/x86/kernel/nmi_64.c | 49 ++++++++++++++++++++++++++++--------------- 2 files changed, 63 insertions(+), 37 deletions(-) diff --git a/arch/x86/kernel/nmi_32.c b/arch/x86/kernel/nmi_32.c index d9266ea..82abc2a 100644 --- a/arch/x86/kernel/nmi_32.c +++ b/arch/x86/kernel/nmi_32.c @@ -325,21 +325,49 @@ extern void die_nmi(struct pt_regs *, const char *msg); int nmi_show_regs[NR_CPUS]; +static DEFINE_RAW_SPINLOCK(nmi_print_lock); + +notrace int irq_show_regs_callback(int cpu, struct pt_regs *regs) +{ + if (!nmi_show_regs[cpu]) + return 0; + + spin_lock(&nmi_print_lock); + printk(KERN_WARNING "NMI show regs on CPU#%d:\n", cpu); + printk(KERN_WARNING "apic_timer_irqs: %d\n", + per_cpu(irq_stat, cpu).apic_timer_irqs); + show_regs(regs); + spin_unlock(&nmi_print_lock); + nmi_show_regs[cpu] = 0; + return 1; +} + void nmi_show_all_regs(void) { - int i; + struct pt_regs *regs; + int i, cpu; if (system_state == SYSTEM_BOOTING) return; - printk(KERN_WARNING "nmi_show_all_regs(): start on CPU#%d.\n", - raw_smp_processor_id()); + preempt_disable(); + + regs = get_irq_regs(); + cpu = smp_processor_id(); + + printk(KERN_WARNING "nmi_show_all_regs(): start on CPU#%d.\n", cpu); dump_stack(); for_each_online_cpu(i) nmi_show_regs[i] = 1; + if (regs) + irq_show_regs_callback(cpu, regs); + else + nmi_show_regs[cpu] = 0; + smp_send_nmi_allbutself(); + preempt_enable(); for_each_online_cpu(i) { while (nmi_show_regs[i] == 1) @@ -347,23 +375,6 @@ void nmi_show_all_regs(void) } } -static DEFINE_RAW_SPINLOCK(nmi_print_lock); - -notrace int irq_show_regs_callback(int cpu, struct pt_regs *regs) -{ - if (!nmi_show_regs[cpu]) - return 0; - - spin_lock(&nmi_print_lock); - printk(KERN_WARNING "NMI show regs on CPU#%d:\n", cpu); - printk(KERN_WARNING "apic_timer_irqs: %d\n", - per_cpu(irq_stat, cpu).apic_timer_irqs); - show_regs(regs); - spin_unlock(&nmi_print_lock); - nmi_show_regs[cpu] = 0; - return 1; -} - __kprobes int nmi_watchdog_tick(struct pt_regs * regs, unsigned reason) { diff --git a/arch/x86/kernel/nmi_64.c b/arch/x86/kernel/nmi_64.c index c802380..5e7e2b0 100644 --- a/arch/x86/kernel/nmi_64.c +++ b/arch/x86/kernel/nmi_64.c @@ -317,17 +317,48 @@ EXPORT_SYMBOL(touch_nmi_watchdog); int nmi_show_regs[NR_CPUS]; +static DEFINE_RAW_SPINLOCK(nmi_print_lock); + +notrace int irq_show_regs_callback(int cpu, struct pt_regs *regs) +{ + if (!nmi_show_regs[cpu]) + return 0; + + spin_lock(&nmi_print_lock); + printk(KERN_WARNING "NMI show regs on CPU#%d:\n", cpu); + printk(KERN_WARNING "apic_timer_irqs: %d\n", read_pda(apic_timer_irqs)); + show_regs(regs); + spin_unlock(&nmi_print_lock); + nmi_show_regs[cpu] = 0; + return 1; +} + void nmi_show_all_regs(void) { - int i; + struct pt_regs *regs; + int i, cpu; if (system_state == SYSTEM_BOOTING) return; + preempt_disable(); + + regs = get_irq_regs(); + cpu = smp_processor_id(); + + printk(KERN_WARNING "nmi_show_all_regs(): start on CPU#%d.\n", cpu); + dump_stack(); + for_each_online_cpu(i) nmi_show_regs[i] = 1; + if (regs) + irq_show_regs_callback(cpu, regs); + else + nmi_show_regs[cpu] = 0; + smp_send_nmi_allbutself(); + preempt_enable(); for_each_online_cpu(i) { while (nmi_show_regs[i] == 1) @@ -335,22 +366,6 @@ void nmi_show_all_regs(void) } } -static DEFINE_RAW_SPINLOCK(nmi_print_lock); - -notrace int irq_show_regs_callback(int cpu, struct pt_regs *regs) -{ - if (!nmi_show_regs[cpu]) - return 0; - - spin_lock(&nmi_print_lock); - printk(KERN_WARNING "NMI show regs on CPU#%d:\n", cpu); - printk(KERN_WARNING "apic_timer_irqs: %d\n", read_pda(apic_timer_irqs)); - show_regs(regs); - spin_unlock(&nmi_print_lock); - nmi_show_regs[cpu] = 0; - return 1; -} - int __kprobes nmi_watchdog_tick(struct pt_regs * regs, unsigned reason) { int sum; -- 1.5.4.1 -- To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
