363 lines
8.1 KiB
C
363 lines
8.1 KiB
C
/*
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* Copyright (C) 1991, 1992 Linus Torvalds
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* Copyright (C) 2000, 2001, 2002 Andi Kleen, SuSE Labs
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*/
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#include <linux/kallsyms.h>
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#include <linux/kprobes.h>
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#include <linux/uaccess.h>
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#include <linux/hardirq.h>
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#include <linux/kdebug.h>
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#include <linux/export.h>
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#include <linux/ptrace.h>
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#include <linux/kexec.h>
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#include <linux/sysfs.h>
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#include <linux/bug.h>
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#include <linux/nmi.h>
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#include <asm/stacktrace.h>
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#define N_EXCEPTION_STACKS_END \
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(N_EXCEPTION_STACKS + DEBUG_STKSZ/EXCEPTION_STKSZ - 2)
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static char x86_stack_ids[][8] = {
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[ DEBUG_STACK-1 ] = "#DB",
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[ NMI_STACK-1 ] = "NMI",
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[ DOUBLEFAULT_STACK-1 ] = "#DF",
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[ MCE_STACK-1 ] = "#MC",
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#if DEBUG_STKSZ > EXCEPTION_STKSZ
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[ N_EXCEPTION_STACKS ...
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N_EXCEPTION_STACKS_END ] = "#DB[?]"
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#endif
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};
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static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack,
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unsigned *usedp, char **idp)
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{
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unsigned k;
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/*
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* Iterate over all exception stacks, and figure out whether
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* 'stack' is in one of them:
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*/
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for (k = 0; k < N_EXCEPTION_STACKS; k++) {
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unsigned long end = per_cpu(orig_ist, cpu).ist[k];
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/*
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* Is 'stack' above this exception frame's end?
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* If yes then skip to the next frame.
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*/
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if (stack >= end)
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continue;
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/*
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* Is 'stack' above this exception frame's start address?
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* If yes then we found the right frame.
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*/
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if (stack >= end - EXCEPTION_STKSZ) {
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/*
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* Make sure we only iterate through an exception
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* stack once. If it comes up for the second time
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* then there's something wrong going on - just
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* break out and return NULL:
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*/
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if (*usedp & (1U << k))
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break;
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*usedp |= 1U << k;
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*idp = x86_stack_ids[k];
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return (unsigned long *)end;
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}
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/*
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* If this is a debug stack, and if it has a larger size than
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* the usual exception stacks, then 'stack' might still
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* be within the lower portion of the debug stack:
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*/
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#if DEBUG_STKSZ > EXCEPTION_STKSZ
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if (k == DEBUG_STACK - 1 && stack >= end - DEBUG_STKSZ) {
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unsigned j = N_EXCEPTION_STACKS - 1;
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/*
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* Black magic. A large debug stack is composed of
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* multiple exception stack entries, which we
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* iterate through now. Dont look:
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*/
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do {
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++j;
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end -= EXCEPTION_STKSZ;
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x86_stack_ids[j][4] = '1' +
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(j - N_EXCEPTION_STACKS);
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} while (stack < end - EXCEPTION_STKSZ);
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if (*usedp & (1U << j))
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break;
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*usedp |= 1U << j;
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*idp = x86_stack_ids[j];
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return (unsigned long *)end;
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}
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#endif
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}
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return NULL;
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}
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static inline int
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in_irq_stack(unsigned long *stack, unsigned long *irq_stack,
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unsigned long *irq_stack_end)
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{
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return (stack >= irq_stack && stack < irq_stack_end);
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}
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static const unsigned long irq_stack_size =
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(IRQ_STACK_SIZE - 64) / sizeof(unsigned long);
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enum stack_type {
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STACK_IS_UNKNOWN,
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STACK_IS_NORMAL,
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STACK_IS_EXCEPTION,
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STACK_IS_IRQ,
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};
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static enum stack_type
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analyze_stack(int cpu, struct task_struct *task, unsigned long *stack,
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unsigned long **stack_end, unsigned long *irq_stack,
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unsigned *used, char **id)
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{
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unsigned long addr;
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addr = ((unsigned long)stack & (~(THREAD_SIZE - 1)));
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if ((unsigned long)task_stack_page(task) == addr)
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return STACK_IS_NORMAL;
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*stack_end = in_exception_stack(cpu, (unsigned long)stack,
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used, id);
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if (*stack_end)
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return STACK_IS_EXCEPTION;
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if (!irq_stack)
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return STACK_IS_NORMAL;
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*stack_end = irq_stack;
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irq_stack = irq_stack - irq_stack_size;
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if (in_irq_stack(stack, irq_stack, *stack_end))
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return STACK_IS_IRQ;
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return STACK_IS_UNKNOWN;
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}
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/*
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* x86-64 can have up to three kernel stacks:
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* process stack
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* interrupt stack
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* severe exception (double fault, nmi, stack fault, debug, mce) hardware stack
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*/
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void dump_trace(struct task_struct *task, struct pt_regs *regs,
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unsigned long *stack, unsigned long bp,
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const struct stacktrace_ops *ops, void *data)
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{
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const unsigned cpu = get_cpu();
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unsigned long *irq_stack = (unsigned long *)per_cpu(irq_stack_ptr, cpu);
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unsigned long dummy;
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unsigned used = 0;
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int graph = 0;
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int done = 0;
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if (!task)
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task = current;
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if (!stack) {
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if (regs)
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stack = (unsigned long *)regs->sp;
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else if (task != current)
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stack = (unsigned long *)task->thread.sp;
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else
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stack = &dummy;
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}
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if (!bp)
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bp = stack_frame(task, regs);
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/*
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* Print function call entries in all stacks, starting at the
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* current stack address. If the stacks consist of nested
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* exceptions
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*/
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while (!done) {
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unsigned long *stack_end;
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enum stack_type stype;
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char *id;
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stype = analyze_stack(cpu, task, stack, &stack_end,
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irq_stack, &used, &id);
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/* Default finish unless specified to continue */
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done = 1;
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switch (stype) {
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/* Break out early if we are on the thread stack */
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case STACK_IS_NORMAL:
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break;
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case STACK_IS_EXCEPTION:
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if (ops->stack(data, id) < 0)
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break;
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bp = ops->walk_stack(task, stack, bp, ops,
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data, stack_end, &graph);
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ops->stack(data, "<EOE>");
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/*
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* We link to the next stack via the
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* second-to-last pointer (index -2 to end) in the
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* exception stack:
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*/
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stack = (unsigned long *) stack_end[-2];
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done = 0;
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break;
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case STACK_IS_IRQ:
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if (ops->stack(data, "IRQ") < 0)
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break;
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bp = ops->walk_stack(task, stack, bp,
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ops, data, stack_end, &graph);
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/*
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* We link to the next stack (which would be
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* the process stack normally) the last
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* pointer (index -1 to end) in the IRQ stack:
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*/
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stack = (unsigned long *) (stack_end[-1]);
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irq_stack = NULL;
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ops->stack(data, "EOI");
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done = 0;
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break;
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case STACK_IS_UNKNOWN:
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ops->stack(data, "UNK");
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break;
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}
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}
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/*
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* This handles the process stack:
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*/
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bp = ops->walk_stack(task, stack, bp, ops, data, NULL, &graph);
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put_cpu();
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}
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EXPORT_SYMBOL(dump_trace);
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void
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show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
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unsigned long *sp, unsigned long bp, char *log_lvl)
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{
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unsigned long *irq_stack_end;
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unsigned long *irq_stack;
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unsigned long *stack;
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int cpu;
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int i;
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preempt_disable();
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cpu = smp_processor_id();
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irq_stack_end = (unsigned long *)(per_cpu(irq_stack_ptr, cpu));
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irq_stack = (unsigned long *)(per_cpu(irq_stack_ptr, cpu) - IRQ_STACK_SIZE);
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/*
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* Debugging aid: "show_stack(NULL, NULL);" prints the
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* back trace for this cpu:
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*/
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if (sp == NULL) {
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if (regs)
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sp = (unsigned long *)regs->sp;
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else if (task)
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sp = (unsigned long *)task->thread.sp;
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else
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sp = (unsigned long *)&sp;
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}
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stack = sp;
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for (i = 0; i < kstack_depth_to_print; i++) {
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unsigned long word;
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if (stack >= irq_stack && stack <= irq_stack_end) {
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if (stack == irq_stack_end) {
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stack = (unsigned long *) (irq_stack_end[-1]);
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pr_cont(" <EOI> ");
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}
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} else {
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if (kstack_end(stack))
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break;
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}
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if (probe_kernel_address(stack, word))
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break;
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if ((i % STACKSLOTS_PER_LINE) == 0) {
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if (i != 0)
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pr_cont("\n");
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printk("%s %016lx", log_lvl, word);
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} else
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pr_cont(" %016lx", word);
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stack++;
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touch_nmi_watchdog();
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}
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preempt_enable();
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pr_cont("\n");
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show_trace_log_lvl(task, regs, sp, bp, log_lvl);
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}
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void show_regs(struct pt_regs *regs)
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{
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int i;
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unsigned long sp;
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sp = regs->sp;
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show_regs_print_info(KERN_DEFAULT);
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__show_regs(regs, 1);
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/*
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* When in-kernel, we also print out the stack and code at the
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* time of the fault..
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*/
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if (!user_mode(regs)) {
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unsigned int code_prologue = code_bytes * 43 / 64;
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unsigned int code_len = code_bytes;
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unsigned char c;
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u8 *ip;
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printk(KERN_DEFAULT "Stack:\n");
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show_stack_log_lvl(NULL, regs, (unsigned long *)sp,
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0, KERN_DEFAULT);
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printk(KERN_DEFAULT "Code: ");
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ip = (u8 *)regs->ip - code_prologue;
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if (ip < (u8 *)PAGE_OFFSET || probe_kernel_address(ip, c)) {
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/* try starting at IP */
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ip = (u8 *)regs->ip;
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code_len = code_len - code_prologue + 1;
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}
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for (i = 0; i < code_len; i++, ip++) {
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if (ip < (u8 *)PAGE_OFFSET ||
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probe_kernel_address(ip, c)) {
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pr_cont(" Bad RIP value.");
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break;
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}
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if (ip == (u8 *)regs->ip)
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pr_cont("<%02x> ", c);
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else
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pr_cont("%02x ", c);
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}
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}
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pr_cont("\n");
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}
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int is_valid_bugaddr(unsigned long ip)
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{
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unsigned short ud2;
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if (__copy_from_user(&ud2, (const void __user *) ip, sizeof(ud2)))
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return 0;
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return ud2 == 0x0b0f;
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}
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