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- // 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/atomic.h>
- #include <linux/kexec.h>
- #include <linux/utsname.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);
- 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);
- 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:
- local_irq_save(flags);
- 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 {
- local_irq_restore(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);
- local_irq_restore(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);
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