Something went wrong. Try again.
(I'm so sorry!) Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel os linux
Something went wrong. Try again.
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140// SPDX-License-Identifier: GPL-2.0/* * NMI backtrace support * * Gratuitously copied from arch/x86/kernel/apic/hw_nmi.c by Russell King, * with the following header: * * HW NMI watchdog support * * started by Don Zickus, Copyright (C) 2010 Red Hat, Inc. * * Arch specific calls to support NMI watchdog * * Bits copied from original nmi.c file */#include <linux/cpumask.h>#include <linux/delay.h>#include <linux/kprobes.h>#include <linux/stringify.h>#include <linux/nmi.h>#include <linux/cpu.h>#include <linux/export.h>#include <linux/sched/debug.h>
#ifdef arch_trigger_cpumask_backtrace/* For reliability, we're prepared to waste bits here. */static DECLARE_BITMAP(backtrace_mask, NR_CPUS) __read_mostly;
/* "in progress" flag of arch_trigger_cpumask_backtrace */static unsigned long backtrace_flag;
#define NMI_BT_TIMEOUT_SEC 10
/* * When raise() is called it will be passed a pointer to the * backtrace_mask. Architectures that call nmi_cpu_backtrace() * directly from their raise() functions may rely on the mask * they are passed being updated as a side effect of this call. */void nmi_trigger_cpumask_backtrace(const cpumask_t *mask, int exclude_cpu, void (*raise)(cpumask_t *mask)){ int i, this_cpu = get_cpu();
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), 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 * architectures, but on others it may not, and we'll get * information at least as useful just by doing a dump_stack() here. * Note that nmi_cpu_backtrace(NULL) will clear the cpu bit. */ if (cpumask_test_cpu(this_cpu, to_cpumask(backtrace_mask))) nmi_cpu_backtrace(NULL);
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)); }
/* Wait for up to NMI_BT_TIMEOUT_SEC seconds for all CPUs to do the backtrace */ for (i = 0; i < NMI_BT_TIMEOUT_SEC * 1000; i++) { if (cpumask_empty(to_cpumask(backtrace_mask))) break; mdelay(1); touch_softlockup_watchdog(); }
if (!cpumask_empty(to_cpumask(backtrace_mask))) { pr_warn("After " __stringify(NMI_BT_TIMEOUT_SEC) " seconds, these CPUS still haven't responded to the NMI: %*pbl\n", cpumask_pr_args(to_cpumask(backtrace_mask)));
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_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){ int cpu = smp_processor_id(); unsigned long flags;
if (cpumask_test_cpu(cpu, to_cpumask(backtrace_mask))) { /* * 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) show_regs(regs); else dump_stack(); } printk_cpu_sync_put_irqrestore(flags); cpumask_clear_cpu(cpu, to_cpumask(backtrace_mask)); return true; }
return false;}NOKPROBE_SYMBOL(nmi_cpu_backtrace);
void cpumask_backtrace(const cpumask_t *mask, int exclude_cpu){ arch_trigger_cpumask_backtrace(mask, exclude_cpu);}EXPORT_SYMBOL_GPL(cpumask_backtrace);#endif