140 lines
3.1 KiB
C
140 lines
3.1 KiB
C
/*
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* Stack trace management functions
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*
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* Copyright (C) 2006-2009 Red Hat, Inc., Ingo Molnar <mingo@redhat.com>
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*/
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#include <linux/sched.h>
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#include <linux/stacktrace.h>
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#include <linux/export.h>
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#include <linux/uaccess.h>
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#include <asm/stacktrace.h>
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#include <asm/unwind.h>
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static int save_stack_address(struct stack_trace *trace, unsigned long addr,
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bool nosched)
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{
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if (nosched && in_sched_functions(addr))
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return 0;
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if (trace->skip > 0) {
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trace->skip--;
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return 0;
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}
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if (trace->nr_entries >= trace->max_entries)
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return -1;
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trace->entries[trace->nr_entries++] = addr;
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return 0;
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}
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static void __save_stack_trace(struct stack_trace *trace,
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struct task_struct *task, struct pt_regs *regs,
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bool nosched)
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{
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struct unwind_state state;
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unsigned long addr;
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if (regs)
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save_stack_address(trace, regs->ip, nosched);
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for (unwind_start(&state, task, regs, NULL); !unwind_done(&state);
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unwind_next_frame(&state)) {
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addr = unwind_get_return_address(&state);
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if (!addr || save_stack_address(trace, addr, nosched))
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break;
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}
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if (trace->nr_entries < trace->max_entries)
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trace->entries[trace->nr_entries++] = ULONG_MAX;
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}
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/*
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* Save stack-backtrace addresses into a stack_trace buffer.
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*/
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void save_stack_trace(struct stack_trace *trace)
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{
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__save_stack_trace(trace, current, NULL, false);
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}
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EXPORT_SYMBOL_GPL(save_stack_trace);
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void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
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{
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__save_stack_trace(trace, current, regs, false);
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}
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void save_stack_trace_tsk(struct task_struct *tsk, struct stack_trace *trace)
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{
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if (!try_get_task_stack(tsk))
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return;
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__save_stack_trace(trace, tsk, NULL, true);
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put_task_stack(tsk);
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}
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EXPORT_SYMBOL_GPL(save_stack_trace_tsk);
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/* Userspace stacktrace - based on kernel/trace/trace_sysprof.c */
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struct stack_frame_user {
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const void __user *next_fp;
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unsigned long ret_addr;
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};
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static int
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copy_stack_frame(const void __user *fp, struct stack_frame_user *frame)
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{
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int ret;
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if (!access_ok(VERIFY_READ, fp, sizeof(*frame)))
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return 0;
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ret = 1;
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pagefault_disable();
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if (__copy_from_user_inatomic(frame, fp, sizeof(*frame)))
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ret = 0;
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pagefault_enable();
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return ret;
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}
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static inline void __save_stack_trace_user(struct stack_trace *trace)
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{
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const struct pt_regs *regs = task_pt_regs(current);
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const void __user *fp = (const void __user *)regs->bp;
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if (trace->nr_entries < trace->max_entries)
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trace->entries[trace->nr_entries++] = regs->ip;
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while (trace->nr_entries < trace->max_entries) {
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struct stack_frame_user frame;
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frame.next_fp = NULL;
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frame.ret_addr = 0;
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if (!copy_stack_frame(fp, &frame))
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break;
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if ((unsigned long)fp < regs->sp)
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break;
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if (frame.ret_addr) {
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trace->entries[trace->nr_entries++] =
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frame.ret_addr;
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}
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if (fp == frame.next_fp)
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break;
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fp = frame.next_fp;
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}
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}
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void save_stack_trace_user(struct stack_trace *trace)
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{
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/*
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* Trace user stack if we are not a kernel thread
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*/
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if (current->mm) {
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__save_stack_trace_user(trace);
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}
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if (trace->nr_entries < trace->max_entries)
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trace->entries[trace->nr_entries++] = ULONG_MAX;
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}
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