forked from Minki/linux
e18bcccd1a
Convert show_trace_log_lvl() to use the new unwinder. dump_trace() has been deprecated. show_trace_log_lvl() is special compared to other users of the unwinder. It's the only place where both reliable *and* unreliable addresses are needed. With frame pointers enabled, most callers of the unwinder don't want to know about unreliable addresses. But in this case, when we're dumping the stack to the console because something presumably went wrong, the unreliable addresses are useful: - They show stale data on the stack which can provide useful clues. - If something goes wrong with the unwinder, or if frame pointers are corrupt or missing, all the stack addresses still get shown. So in order to show all addresses on the stack, and at the same time figure out which addresses are reliable, we have to do the scanning and the unwinding in parallel. The scanning is done with the help of get_stack_info() to traverse the stacks. The unwinding is done separately by the new unwinder. In theory we could simplify show_trace_log_lvl() by instead pushing some of this logic into the unwind code. But then we would need some kind of "fake" frame logic in the unwinder which would add a lot of complexity and wouldn't be worth it in order to support only one user. Another benefit of this approach is that once we have a DWARF unwinder, we should be able to just plug it in with minimal impact to this code. Another change here is that callers of show_trace_log_lvl() don't need to provide the 'bp' argument. The unwinder already finds the relevant frame pointer by unwinding until it reaches the first frame after the provided stack pointer. Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Andy Lutomirski <luto@amacapital.net> Cc: Andy Lutomirski <luto@kernel.org> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Byungchul Park <byungchul.park@lge.com> Cc: Denys Vlasenko <dvlasenk@redhat.com> Cc: Frederic Weisbecker <fweisbec@gmail.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Nilay Vaish <nilayvaish@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Thomas Gleixner <tglx@linutronix.de> Link: http://lkml.kernel.org/r/703b5998604c712a1f801874b43f35d6dac52ede.1474045023.git.jpoimboe@redhat.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
243 lines
5.1 KiB
C
243 lines
5.1 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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void stack_type_str(enum stack_type type, const char **begin, const char **end)
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{
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switch (type) {
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case STACK_TYPE_IRQ:
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case STACK_TYPE_SOFTIRQ:
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*begin = "IRQ";
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*end = "EOI";
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break;
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default:
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*begin = NULL;
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*end = NULL;
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}
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}
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static bool in_hardirq_stack(unsigned long *stack, struct stack_info *info)
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{
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unsigned long *begin = (unsigned long *)this_cpu_read(hardirq_stack);
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unsigned long *end = begin + (THREAD_SIZE / sizeof(long));
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/*
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* This is a software stack, so 'end' can be a valid stack pointer.
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* It just means the stack is empty.
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*/
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if (stack < begin || stack > end)
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return false;
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info->type = STACK_TYPE_IRQ;
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info->begin = begin;
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info->end = end;
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/*
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* See irq_32.c -- the next stack pointer is stored at the beginning of
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* the stack.
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*/
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info->next_sp = (unsigned long *)*begin;
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return true;
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}
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static bool in_softirq_stack(unsigned long *stack, struct stack_info *info)
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{
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unsigned long *begin = (unsigned long *)this_cpu_read(softirq_stack);
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unsigned long *end = begin + (THREAD_SIZE / sizeof(long));
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/*
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* This is a software stack, so 'end' can be a valid stack pointer.
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* It just means the stack is empty.
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*/
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if (stack < begin || stack > end)
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return false;
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info->type = STACK_TYPE_SOFTIRQ;
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info->begin = begin;
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info->end = end;
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/*
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* The next stack pointer is stored at the beginning of the stack.
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* See irq_32.c.
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*/
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info->next_sp = (unsigned long *)*begin;
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return true;
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}
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int get_stack_info(unsigned long *stack, struct task_struct *task,
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struct stack_info *info, unsigned long *visit_mask)
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{
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if (!stack)
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goto unknown;
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task = task ? : current;
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if (in_task_stack(stack, task, info))
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goto recursion_check;
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if (task != current)
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goto unknown;
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if (in_hardirq_stack(stack, info))
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goto recursion_check;
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if (in_softirq_stack(stack, info))
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goto recursion_check;
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goto unknown;
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recursion_check:
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/*
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* Make sure we don't iterate through any given stack more than once.
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* If it comes up a second time then there's something wrong going on:
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* just break out and report an unknown stack type.
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*/
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if (visit_mask) {
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if (*visit_mask & (1UL << info->type))
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goto unknown;
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*visit_mask |= 1UL << info->type;
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}
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return 0;
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unknown:
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info->type = STACK_TYPE_UNKNOWN;
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return -EINVAL;
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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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unsigned long visit_mask = 0;
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int graph = 0;
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task = task ? : current;
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stack = stack ? : get_stack_pointer(task, regs);
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bp = bp ? : (unsigned long)get_frame_pointer(task, regs);
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for (;;) {
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const char *begin_str, *end_str;
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struct stack_info info;
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if (get_stack_info(stack, task, &info, &visit_mask))
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break;
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stack_type_str(info.type, &begin_str, &end_str);
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if (begin_str && ops->stack(data, begin_str) < 0)
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break;
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bp = ops->walk_stack(task, stack, bp, ops, data, &info, &graph);
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if (end_str && ops->stack(data, end_str) < 0)
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break;
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stack = info.next_sp;
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touch_nmi_watchdog();
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}
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}
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EXPORT_SYMBOL(dump_trace);
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void show_stack_log_lvl(struct task_struct *task, struct pt_regs *regs,
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unsigned long *sp, char *log_lvl)
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{
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unsigned long *stack;
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int i;
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if (!try_get_task_stack(task))
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return;
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sp = sp ? : get_stack_pointer(task, regs);
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stack = sp;
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for (i = 0; i < kstack_depth_to_print; i++) {
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if (kstack_end(stack))
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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 %08lx", log_lvl, *stack++);
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} else
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pr_cont(" %08lx", *stack++);
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touch_nmi_watchdog();
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}
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pr_cont("\n");
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show_trace_log_lvl(task, regs, sp, log_lvl);
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put_task_stack(task);
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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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show_regs_print_info(KERN_EMERG);
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__show_regs(regs, !user_mode(regs));
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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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pr_emerg("Stack:\n");
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show_stack_log_lvl(current, regs, NULL, KERN_EMERG);
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pr_emerg("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 EIP 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 (ip < PAGE_OFFSET)
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return 0;
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if (probe_kernel_address((unsigned short *)ip, ud2))
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return 0;
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return ud2 == 0x0b0f;
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}
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