diff options
Diffstat (limited to 'lib/nmi_backtrace.c')
| -rw-r--r-- | lib/nmi_backtrace.c | 31 |
1 files changed, 21 insertions, 10 deletions
diff --git a/lib/nmi_backtrace.c b/lib/nmi_backtrace.c index 0bc0a3535a8a..33c154264bfe 100644 --- a/lib/nmi_backtrace.c +++ b/lib/nmi_backtrace.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0 /* * NMI backtrace support * @@ -33,7 +34,7 @@ static unsigned long backtrace_flag; * they are passed being updated as a side effect of this call. */ void nmi_trigger_cpumask_backtrace(const cpumask_t *mask, - bool exclude_self, + int exclude_cpu, void (*raise)(cpumask_t *mask)) { int i, this_cpu = get_cpu(); @@ -48,8 +49,8 @@ void nmi_trigger_cpumask_backtrace(const cpumask_t *mask, } cpumask_copy(to_cpumask(backtrace_mask), mask); - if (exclude_self) - cpumask_clear_cpu(this_cpu, to_cpumask(backtrace_mask)); + if (exclude_cpu != -1) + cpumask_clear_cpu(exclude_cpu, to_cpumask(backtrace_mask)); /* * Don't try to send an NMI to this cpu; it may work on some @@ -63,6 +64,7 @@ void nmi_trigger_cpumask_backtrace(const cpumask_t *mask, if (!cpumask_empty(to_cpumask(backtrace_mask))) { pr_info("Sending NMI from CPU %d to CPUs %*pbl:\n", this_cpu, nr_cpumask_bits, to_cpumask(backtrace_mask)); + nmi_backtrace_stall_snap(to_cpumask(backtrace_mask)); raise(to_cpumask(backtrace_mask)); } @@ -73,27 +75,36 @@ void nmi_trigger_cpumask_backtrace(const cpumask_t *mask, mdelay(1); touch_softlockup_watchdog(); } + nmi_backtrace_stall_check(to_cpumask(backtrace_mask)); /* * Force flush any remote buffers that might be stuck in IRQ context * and therefore could not run their irq_work. */ - printk_safe_flush(); + printk_trigger_flush(); clear_bit_unlock(0, &backtrace_flag); put_cpu(); } +// Dump stacks even for idle CPUs. +static bool backtrace_idle; +module_param(backtrace_idle, bool, 0644); + bool nmi_cpu_backtrace(struct pt_regs *regs) { - static arch_spinlock_t lock = __ARCH_SPIN_LOCK_UNLOCKED; int cpu = smp_processor_id(); + unsigned long flags; if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) { - arch_spin_lock(&lock); - if (regs && cpu_in_idle(instruction_pointer(regs))) { - pr_warn("NMI backtrace for cpu %d skipped: idling at pc %#lx\n", - cpu, instruction_pointer(regs)); + /* + * Allow nested NMI backtraces while serializing + * against other CPUs. + */ + printk_cpu_sync_get_irqsave(flags); + if (!READ_ONCE(backtrace_idle) && regs && cpu_in_idle(instruction_pointer(regs))) { + pr_warn("NMI backtrace for cpu %d skipped: idling at %pS\n", + cpu, (void *)instruction_pointer(regs)); } else { pr_warn("NMI backtrace for cpu %d\n", cpu); if (regs) @@ -101,7 +112,7 @@ bool nmi_cpu_backtrace(struct pt_regs *regs) else dump_stack(); } - arch_spin_unlock(&lock); + printk_cpu_sync_put_irqrestore(flags); cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask)); return true; } |