29a679754b
If we return -1 in the ops->stack for the stacktrace saving, we end up
breaking out of the loop if the stack we are tracing is in the exception
stack. This causes traces like:
<idle>-0 [002] 34263.745825: raise_softirq_irqoff <-__blk_complete_request
<idle>-0 [002] 34263.745826:
<= 0
<= 0
<= 0
<= 0
<= 0
<= 0
<= 0
By returning "0" instead, the irq stack is saved as well, and we see:
<idle>-0 [003] 883.280992: raise_softirq_irqoff <-__hrtimer_star
t_range_ns
<idle>-0 [003] 883.280992:
<= hrtimer_start_range_ns
<= tick_nohz_restart_sched_tick
<= cpu_idle
<= start_secondary
<=
<= 0
<= 0
[ Impact: record stacks from interrupts ]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
149 lines
3.4 KiB
C
149 lines
3.4 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/module.h>
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#include <linux/uaccess.h>
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#include <asm/stacktrace.h>
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static void save_stack_warning(void *data, char *msg)
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{
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}
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static void
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save_stack_warning_symbol(void *data, char *msg, unsigned long symbol)
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{
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}
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static int save_stack_stack(void *data, char *name)
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{
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return 0;
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}
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static void save_stack_address(void *data, unsigned long addr, int reliable)
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{
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struct stack_trace *trace = data;
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if (!reliable)
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return;
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if (trace->skip > 0) {
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trace->skip--;
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return;
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}
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if (trace->nr_entries < trace->max_entries)
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trace->entries[trace->nr_entries++] = addr;
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}
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static void
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save_stack_address_nosched(void *data, unsigned long addr, int reliable)
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{
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struct stack_trace *trace = (struct stack_trace *)data;
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if (!reliable)
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return;
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if (in_sched_functions(addr))
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return;
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if (trace->skip > 0) {
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trace->skip--;
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return;
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}
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if (trace->nr_entries < trace->max_entries)
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trace->entries[trace->nr_entries++] = addr;
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}
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static const struct stacktrace_ops save_stack_ops = {
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.warning = save_stack_warning,
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.warning_symbol = save_stack_warning_symbol,
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.stack = save_stack_stack,
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.address = save_stack_address,
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};
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static const struct stacktrace_ops save_stack_ops_nosched = {
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.warning = save_stack_warning,
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.warning_symbol = save_stack_warning_symbol,
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.stack = save_stack_stack,
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.address = save_stack_address_nosched,
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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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dump_trace(current, NULL, NULL, 0, &save_stack_ops, trace);
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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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EXPORT_SYMBOL_GPL(save_stack_trace);
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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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dump_trace(tsk, NULL, NULL, 0, &save_stack_ops_nosched, trace);
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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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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 {
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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 copy_stack_frame(const void __user *fp, struct stack_frame *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 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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