Commit feaf1283 authored Jun 22, 2017 by Steven Rostedt (VMware)

tracing: Show address when function names are not found



Currently, when a function is not found in kallsyms, instead of simply
showing the function address, it shows nothing at all:

 # echo ':mod:kvm_intel' > /sys/kernel/tracing/set_ftrace_filter
 # echo function > /sys/kernel/tracing/set_ftrace_filter
 # qemu -enable-kvm /home/my-qemu-image
   <Ctrl-C>
 # rmmod kvm_intel
 # cat /sys/kernel/tracing/trace
 qemu-system-x86-2408  [001] d..2   135.013238:  <-kvm_arch_hardware_enable
 qemu-system-x86-2408  [001] ....   135.014574:  <-kvm_arch_vm_ioctl
 qemu-system-x86-2408  [001] ....   135.015420:  <-kvm_vm_ioctl_check_extension
 qemu-system-x86-2408  [001] ....   135.045411:  <-__do_cpuid_ent
 qemu-system-x86-2408  [001] ....   135.045412:  <-__do_cpuid_ent
 qemu-system-x86-2408  [001] ....   135.045412:  <-__do_cpuid_ent
 qemu-system-x86-2408  [001] ....   135.045412:  <-__do_cpuid_ent
 qemu-system-x86-2408  [001] ...1   135.045413:  <-__do_cpuid_ent
 qemu-system-x86-2408  [001] ....   135.045413:  <-__do_cpuid_ent

When it should show:

 qemu-system-x86-2408  [001] d..2   135.013238: 0xffffffffa02a39f0 <-kvm_arch_hardware_enable
 qemu-system-x86-2408  [001] ....   135.014574: 0xffffffffa02a2ba0 <-kvm_arch_vm_ioctl
 qemu-system-x86-2408  [001] ....   135.015420: 0xffffffffa029e4e0 <-kvm_vm_ioctl_check_extension
 qemu-system-x86-2408  [001] ....   135.045411: 0xffffffffa02a1380 <-__do_cpuid_ent
 qemu-system-x86-2408  [001] ....   135.045412: 0xffffffffa029e160 <-__do_cpuid_ent
 qemu-system-x86-2408  [001] ....   135.045412: 0xffffffffa029e180 <-__do_cpuid_ent
 qemu-system-x86-2408  [001] ....   135.045412: 0xffffffffa029e520 <-__do_cpuid_ent
 qemu-system-x86-2408  [001] ...1   135.045413: 0xffffffffa02a13b0 <-__do_cpuid_ent
 qemu-system-x86-2408  [001] ....   135.045413: 0xffffffffa02a1380 <-__do_cpuid_ent

instead.

Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>

parent d0ba52f1

kernel/trace/trace_output.c

+14 −4

Original line number	Diff line number	Diff line
		@@ -340,31 +340,41 @@ static inline const char kretprobed(const char name)
		static void
		seq_print_sym_short(struct trace_seq s, const char fmt, unsigned long address)
		{
		#ifdef CONFIG_KALLSYMS
		char str[KSYM_SYMBOL_LEN];
		#ifdef CONFIG_KALLSYMS
		const char *name;

		kallsyms_lookup(address, NULL, NULL, NULL, str);

		name = kretprobed(str);

		if (name && strlen(name)) {
		trace_seq_printf(s, fmt, name);
		return;
		}
		#endif
		snprintf(str, KSYM_SYMBOL_LEN, "0x%08lx", address);
		trace_seq_printf(s, fmt, str);
		}

		static void
		seq_print_sym_offset(struct trace_seq s, const char fmt,
		unsigned long address)
		{
		#ifdef CONFIG_KALLSYMS
		char str[KSYM_SYMBOL_LEN];
		#ifdef CONFIG_KALLSYMS
		const char *name;

		sprint_symbol(str, address);
		name = kretprobed(str);

		if (name && strlen(name)) {
		trace_seq_printf(s, fmt, name);
		return;
		}
		#endif
		snprintf(str, KSYM_SYMBOL_LEN, "0x%08lx", address);
		trace_seq_printf(s, fmt, str);
		}

		#ifndef CONFIG_64BIT

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