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From: Steven Rostedt <rostedt@goodmis.org>
To: linux-kernel@vger.kernel.org
Cc: Ingo Molnar <mingo@kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>
Subject: [for-next][PATCH 02/12] tracing: Show address when function names are not found
Date: Thu, 29 Jun 2017 20:38:33 -0400	[thread overview]
Message-ID: <20170630004021.985664372@goodmis.org> (raw)
In-Reply-To: 20170630003831.946074263@goodmis.org

[-- Attachment #1: 0002-tracing-Show-address-when-function-names-are-not-fou.patch --]
[-- Type: text/plain, Size: 3275 bytes --]

From: "Steven Rostedt (VMware)" <rostedt@goodmis.org>

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>
---
 kernel/trace/trace_output.c | 18 ++++++++++++++----
 1 file changed, 14 insertions(+), 4 deletions(-)

diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 08f9bab8089e..01ff99969ca7 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -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);
 
-	trace_seq_printf(s, fmt, name);
+	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);
 
-	trace_seq_printf(s, fmt, name);
+	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
-- 
2.10.2

  parent reply	other threads:[~2017-06-30  0:40 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-06-30  0:38 [for-next][PATCH 00/12] tracing: More updates for 4.13 Steven Rostedt
2017-06-30  0:38 ` [for-next][PATCH 01/12] ftrace: Add missing comment for FTRACE_OPS_FL_RCU Steven Rostedt
2017-06-30  0:38 ` Steven Rostedt [this message]
2017-06-30  0:38 ` [for-next][PATCH 03/12] ftrace: Add :mod: caching infrastructure to trace_array Steven Rostedt
2017-06-30  0:38 ` [for-next][PATCH 04/12] ftrace: Have the cached module list show in set_ftrace_filter Steven Rostedt
2017-06-30  0:38 ` [for-next][PATCH 05/12] ftrace: Implement cached modules tracing on module load Steven Rostedt
2017-06-30  0:38 ` [for-next][PATCH 06/12] ftrace: Have cached module filters be an active filter Steven Rostedt
2017-06-30  0:38 ` [for-next][PATCH 07/12] sh/ftrace: Remove only user of ftrace_arch_read_dyn_info() Steven Rostedt
2017-06-30  0:38   ` Steven Rostedt
2017-06-30  0:38 ` [for-next][PATCH 08/12] ftrace: Remove unused function ftrace_arch_read_dyn_info() Steven Rostedt
2017-06-30  0:38 ` [for-next][PATCH 09/12] ftrace: Decrement count for dyn_ftrace_total_info file Steven Rostedt
2017-06-30  0:38 ` [for-next][PATCH 10/12] tracing: Add support for recording tgid of tasks Steven Rostedt
2017-06-30  0:38 ` [for-next][PATCH 11/12] tracing: Add support for display of tgid in trace output Steven Rostedt
2017-06-30  0:38 ` [for-next][PATCH 12/12] ftrace: Unlock hash mutex on failed allocation in process_mod_list() Steven Rostedt

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