Release 4.18 arch/x86/kernel/dumpstack_64.c

// SPDX-License-Identifier: GPL-2.0
/*
 *  Copyright (C) 1991, 1992  Linus Torvalds
 *  Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
 */
#include <linux/sched/debug.h>
#include <linux/kallsyms.h>
#include <linux/kprobes.h>
#include <linux/uaccess.h>
#include <linux/hardirq.h>
#include <linux/kdebug.h>
#include <linux/export.h>
#include <linux/ptrace.h>
#include <linux/kexec.h>
#include <linux/sysfs.h>
#include <linux/bug.h>
#include <linux/nmi.h>

#include <asm/stacktrace.h>


static char *exception_stack_names[N_EXCEPTION_STACKS] = {
		[ DOUBLEFAULT_STACK-1	]	= "#DF",
		[ NMI_STACK-1		]	= "NMI",
		[ DEBUG_STACK-1		]	= "#DB",
		[ MCE_STACK-1		]	= "#MC",
};


static unsigned long exception_stack_sizes[N_EXCEPTION_STACKS] = {
	[0 ... N_EXCEPTION_STACKS - 1]		= EXCEPTION_STKSZ,
	[DEBUG_STACK - 1]			= DEBUG_STKSZ
};



const char *stack_type_name(enum stack_type type)
{
	BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);

	if (type == STACK_TYPE_IRQ)
		return "IRQ";

	if (type == STACK_TYPE_ENTRY) {
		/*
                 * On 64-bit, we have a generic entry stack that we
                 * use for all the kernel entry points, including
                 * SYSENTER.
                 */
		return "ENTRY_TRAMPOLINE";
	}

	if (type >= STACK_TYPE_EXCEPTION && type <= STACK_TYPE_EXCEPTION_LAST)
		return exception_stack_names[type - STACK_TYPE_EXCEPTION];

	return NULL;
}

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8.33%
1
25.00%
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60
100.00%
4
100.00%



static bool in_exception_stack(unsigned long *stack, struct stack_info *info)
{
	unsigned long *begin, *end;
	struct pt_regs *regs;
	unsigned k;

	BUILD_BUG_ON(N_EXCEPTION_STACKS != 4);

	for (k = 0; k < N_EXCEPTION_STACKS; k++) {
		end   = (unsigned long *)raw_cpu_ptr(&orig_ist)->ist[k];
		begin = end - (exception_stack_sizes[k] / sizeof(long));
		regs  = (struct pt_regs *)end - 1;

		if (stack <= begin || stack >= end)
			continue;

		info->type	= STACK_TYPE_EXCEPTION + k;
		info->begin	= begin;
		info->end	= end;
		info->next_sp	= (unsigned long *)regs->sp;

		return true;
	}

	return false;
}

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9
6.04%
1
16.67%
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149
100.00%
6
100.00%



static bool in_irq_stack(unsigned long *stack, struct stack_info *info)
{
	unsigned long *end   = (unsigned long *)this_cpu_read(irq_stack_ptr);
	unsigned long *begin = end - (IRQ_STACK_SIZE / sizeof(long));

	/*
         * This is a software stack, so 'end' can be a valid stack pointer.
         * It just means the stack is empty.
         */
	if (stack <= begin || stack > end)
		return false;

	info->type	= STACK_TYPE_IRQ;
	info->begin	= begin;
	info->end	= end;

	/*
         * The next stack pointer is the first thing pushed by the entry code
         * after switching to the irq stack.
         */
	info->next_sp = (unsigned long *)*(end - 1);

	return true;
}

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19
19.19%
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25.00%
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99
100.00%
4
100.00%



int get_stack_info(unsigned long *stack, struct task_struct *task,
		   struct stack_info *info, unsigned long *visit_mask)
{
	if (!stack)
		goto unknown;

	task = task ? : current;

	if (in_task_stack(stack, task, info))
		goto recursion_check;

	if (task != current)
		goto unknown;

	if (in_exception_stack(stack, info))
		goto recursion_check;

	if (in_irq_stack(stack, info))
		goto recursion_check;

	if (in_entry_stack(stack, info))
		goto recursion_check;

	goto unknown;

recursion_check:
	/*
         * Make sure we don't iterate through any given stack more than once.
         * If it comes up a second time then there's something wrong going on:
         * just break out and report an unknown stack type.
         */
	if (visit_mask) {
		if (*visit_mask & (1UL << info->type)) {
			printk_deferred_once(KERN_WARNING "WARNING: stack recursion on stack type %d\n", info->type);
			goto unknown;
		}
		*visit_mask |= 1UL << info->type;
	}

	return 0;

unknown:
	info->type = STACK_TYPE_UNKNOWN;
	return -EINVAL;
}
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23.93%
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11
6.75%
1
12.50%
Dave Hansen
1
0.61%
1
12.50%
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119
20.45%
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4.76%
Steven Rostedt
39
6.70%
3
14.29%
Frédéric Weisbecker
28
4.81%
2
9.52%
Andrew Lutomirski
18
3.09%
1
4.76%
Dave Hansen
6
1.03%
1
4.76%
Ingo Molnar
6
1.03%
2
9.52%
Andrew Morton
2
0.34%
1
4.76%
Paul Gortmaker
1
0.17%
1
4.76%
Greg Kroah-Hartman
1
0.17%
1
4.76%
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582
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21
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Directory: arch/x86/kernel

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