// SPDX-License-Identifier: GPL-2.0
|
/*
|
* Provide a default dump_stack() function for architectures
|
* which don't implement their own.
|
*/
|
|
#include <linux/kernel.h>
|
#include <linux/export.h>
|
#include <linux/sched.h>
|
#include <linux/sched/debug.h>
|
#include <linux/smp.h>
|
#include <linux/irqstage.h>
|
#include <linux/atomic.h>
|
#include <linux/kexec.h>
|
#include <linux/utsname.h>
|
#include <linux/hardirq.h>
|
|
static char dump_stack_arch_desc_str[128];
|
|
/**
|
* dump_stack_set_arch_desc - set arch-specific str to show with task dumps
|
* @fmt: printf-style format string
|
* @...: arguments for the format string
|
*
|
* The configured string will be printed right after utsname during task
|
* dumps. Usually used to add arch-specific system identifiers. If an
|
* arch wants to make use of such an ID string, it should initialize this
|
* as soon as possible during boot.
|
*/
|
void __init dump_stack_set_arch_desc(const char *fmt, ...)
|
{
|
va_list args;
|
|
va_start(args, fmt);
|
vsnprintf(dump_stack_arch_desc_str, sizeof(dump_stack_arch_desc_str),
|
fmt, args);
|
va_end(args);
|
}
|
|
/**
|
* dump_stack_print_info - print generic debug info for dump_stack()
|
* @log_lvl: log level
|
*
|
* Arch-specific dump_stack() implementations can use this function to
|
* print out the same debug information as the generic dump_stack().
|
*/
|
void dump_stack_print_info(const char *log_lvl)
|
{
|
printk("%sCPU: %d PID: %d Comm: %.20s %s%s %s %.*s\n",
|
log_lvl, raw_smp_processor_id(), current->pid, current->comm,
|
kexec_crash_loaded() ? "Kdump: loaded " : "",
|
print_tainted(),
|
init_utsname()->release,
|
(int)strcspn(init_utsname()->version, " "),
|
init_utsname()->version);
|
|
if (dump_stack_arch_desc_str[0] != '\0')
|
printk("%sHardware name: %s\n",
|
log_lvl, dump_stack_arch_desc_str);
|
|
#ifdef CONFIG_IRQ_PIPELINE
|
printk("%sIRQ stage: %s\n",
|
log_lvl, current_irq_stage->name);
|
#endif
|
|
print_worker_info(log_lvl, current);
|
}
|
|
/**
|
* show_regs_print_info - print generic debug info for show_regs()
|
* @log_lvl: log level
|
*
|
* show_regs() implementations can use this function to print out generic
|
* debug information.
|
*/
|
void show_regs_print_info(const char *log_lvl)
|
{
|
dump_stack_print_info(log_lvl);
|
}
|
|
static void __dump_stack(const char *log_lvl)
|
{
|
dump_stack_print_info(log_lvl);
|
show_stack(NULL, NULL, log_lvl);
|
}
|
|
/**
|
* dump_stack - dump the current task information and its stack trace
|
*
|
* Architectures can override this implementation by implementing its own.
|
*/
|
#ifdef CONFIG_SMP
|
static atomic_t dump_lock = ATOMIC_INIT(-1);
|
|
static unsigned long disable_local_irqs(void)
|
{
|
unsigned long flags = 0; /* only to trick the UMR detection */
|
|
/*
|
* We neither need nor want to disable in-band IRQs over the
|
* oob stage, where CPU migration can't happen. Conversely, we
|
* neither need nor want to disable hard IRQs from the oob
|
* stage, so that latency won't skyrocket as a result of
|
* dumping the stack backtrace.
|
*/
|
if (running_inband() && !on_pipeline_entry())
|
local_irq_save(flags);
|
|
return flags;
|
}
|
|
static void restore_local_irqs(unsigned long flags)
|
{
|
if (running_inband() && !on_pipeline_entry())
|
local_irq_restore(flags);
|
}
|
|
asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
|
{
|
unsigned long flags;
|
int was_locked;
|
int old;
|
int cpu;
|
|
/*
|
* Permit this cpu to perform nested stack dumps while serialising
|
* against other CPUs
|
*/
|
retry:
|
flags = disable_local_irqs();
|
cpu = smp_processor_id();
|
old = atomic_cmpxchg(&dump_lock, -1, cpu);
|
if (old == -1) {
|
was_locked = 0;
|
} else if (old == cpu) {
|
was_locked = 1;
|
} else {
|
restore_local_irqs(flags);
|
/*
|
* Wait for the lock to release before jumping to
|
* atomic_cmpxchg() in order to mitigate the thundering herd
|
* problem.
|
*/
|
do { cpu_relax(); } while (atomic_read(&dump_lock) != -1);
|
goto retry;
|
}
|
|
__dump_stack(log_lvl);
|
|
if (!was_locked)
|
atomic_set(&dump_lock, -1);
|
|
restore_local_irqs(flags);
|
}
|
#else
|
asmlinkage __visible void dump_stack_lvl(const char *log_lvl)
|
{
|
__dump_stack(log_lvl);
|
}
|
#endif
|
EXPORT_SYMBOL(dump_stack_lvl);
|
|
asmlinkage __visible void dump_stack(void)
|
{
|
dump_stack_lvl(KERN_DEFAULT);
|
}
|
EXPORT_SYMBOL(dump_stack);
|
