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https://github.com/torvalds/linux
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e0115875c0
Implement save_stack_trace_regs, so that a stack trace of a kprobe event can be obtained. Without this we see following warning: "save_stack_trace_regs() not implemented yet." when we execute: echo stacktrace > /sys/kernel/debug/tracing/trace_options echo "p kfree" >> /sys/kernel/debug/tracing/kprobe_events echo 1 > /sys/kernel/debug/tracing/events/kprobes/enable Reported-by: Chunyu Hu <chuhu@redhat.com> Signed-off-by: Pratyush Anand <panand@redhat.com> [heiko.carstens@de.ibm.com]: changed patch to use __save_stack_trace() Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com> Tested-by: Peter Oberparleiter <oberpar@linux.vnet.ibm.com> Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
117 lines
3 KiB
C
117 lines
3 KiB
C
/*
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* Stack trace management functions
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*
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* Copyright IBM Corp. 2006
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* Author(s): Heiko Carstens <heiko.carstens@de.ibm.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/kallsyms.h>
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#include <linux/module.h>
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static unsigned long save_context_stack(struct stack_trace *trace,
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unsigned long sp,
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unsigned long low,
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unsigned long high,
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int savesched)
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{
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struct stack_frame *sf;
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struct pt_regs *regs;
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unsigned long addr;
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while(1) {
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if (sp < low || sp > high)
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return sp;
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sf = (struct stack_frame *)sp;
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while(1) {
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addr = sf->gprs[8];
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if (!trace->skip)
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trace->entries[trace->nr_entries++] = addr;
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else
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trace->skip--;
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if (trace->nr_entries >= trace->max_entries)
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return sp;
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low = sp;
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sp = sf->back_chain;
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if (!sp)
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break;
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if (sp <= low || sp > high - sizeof(*sf))
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return sp;
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sf = (struct stack_frame *)sp;
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}
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/* Zero backchain detected, check for interrupt frame. */
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sp = (unsigned long)(sf + 1);
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if (sp <= low || sp > high - sizeof(*regs))
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return sp;
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regs = (struct pt_regs *)sp;
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addr = regs->psw.addr;
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if (savesched || !in_sched_functions(addr)) {
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if (!trace->skip)
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trace->entries[trace->nr_entries++] = addr;
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else
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trace->skip--;
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}
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if (trace->nr_entries >= trace->max_entries)
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return sp;
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low = sp;
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sp = regs->gprs[15];
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}
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}
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static void __save_stack_trace(struct stack_trace *trace, unsigned long sp)
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{
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unsigned long new_sp, frame_size;
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frame_size = STACK_FRAME_OVERHEAD + sizeof(struct pt_regs);
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new_sp = save_context_stack(trace, sp,
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S390_lowcore.panic_stack + frame_size - PAGE_SIZE,
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S390_lowcore.panic_stack + frame_size, 1);
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new_sp = save_context_stack(trace, new_sp,
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S390_lowcore.async_stack + frame_size - ASYNC_SIZE,
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S390_lowcore.async_stack + frame_size, 1);
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save_context_stack(trace, new_sp,
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S390_lowcore.thread_info,
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S390_lowcore.thread_info + THREAD_SIZE, 1);
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}
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void save_stack_trace(struct stack_trace *trace)
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{
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register unsigned long r15 asm ("15");
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unsigned long sp;
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sp = r15;
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__save_stack_trace(trace, sp);
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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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unsigned long sp, low, high;
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sp = tsk->thread.ksp;
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if (tsk == current) {
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/* Get current stack pointer. */
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asm volatile("la %0,0(15)" : "=a" (sp));
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}
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low = (unsigned long) task_stack_page(tsk);
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high = (unsigned long) task_pt_regs(tsk);
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save_context_stack(trace, sp, low, high, 0);
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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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void save_stack_trace_regs(struct pt_regs *regs, struct stack_trace *trace)
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{
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unsigned long sp;
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sp = kernel_stack_pointer(regs);
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__save_stack_trace(trace, sp);
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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_regs);
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