From ec83db0f78cd44c3b586ec1c3a348d1a8a389797 Mon Sep 17 00:00:00 2001 From: Srikar Dronamraju Date: Tue, 8 May 2012 16:41:26 +0530 Subject: [PATCH] tracing: Fix kconfig warning due to a typo Commit f3f096cfe ("tracing: Provide trace events interface for uprobes") throws a warning about unmet dependencies. The exact warning message is: warning: (UPROBE_EVENT) selects UPROBES which has unmet direct dependencies (UPROBE_EVENTS && PERF_EVENTS) This is due to a typo in arch/Kconfig file. Fix similar typos in the uprobetracer documentation. Also add sample format of a uprobe event in the uprobetracer documentation as suggested by Masami Hiramatsu. Reported-by: Stephen Boyd Reported-by: Ingo Molnar Signed-off-by: Srikar Dronamraju Cc: Linus Torvalds Cc: Ananth N Mavinakayanahalli Cc: Oleg Nesterov Cc: Christoph Hellwig Cc: Steven Rostedt Cc: Arnaldo Carvalho de Melo Cc: Masami Hiramatsu Cc: Anton Arapov Cc: Peter Zijlstra Link: http://lkml.kernel.org/r/20120508111126.21004.38285.sendpatchset@srdronam.in.ibm.com Signed-off-by: Ingo Molnar --- Documentation/trace/uprobetracer.txt | 22 ++++++++++++++++++++-- arch/Kconfig | 2 +- 2 files changed, 21 insertions(+), 3 deletions(-) diff --git a/Documentation/trace/uprobetracer.txt b/Documentation/trace/uprobetracer.txt index eae40a003ee..24ce6823a09 100644 --- a/Documentation/trace/uprobetracer.txt +++ b/Documentation/trace/uprobetracer.txt @@ -5,7 +5,7 @@ Overview -------- Uprobe based trace events are similar to kprobe based trace events. -To enable this feature, build your kernel with CONFIG_UPROBE_EVENTS=y. +To enable this feature, build your kernel with CONFIG_UPROBE_EVENT=y. Similar to the kprobe-event tracer, this doesn't need to be activated via current_tracer. Instead of that, add probe points via @@ -68,7 +68,25 @@ in the object. We can see the events that are registered by looking at the uprobe_events file. # cat uprobe_events - p:uprobes/p_zsh_0x46420 /bin/zsh:0x0000000000046420 + p:uprobes/p_zsh_0x46420 /bin/zsh:0x00046420 arg1=%ip arg2=%ax + +The format of events can be seen by viewing the file events/uprobes/p_zsh_0x46420/format + + # cat events/uprobes/p_zsh_0x46420/format + name: p_zsh_0x46420 + ID: 922 + format: + field:unsigned short common_type; offset:0; size:2; signed:0; + field:unsigned char common_flags; offset:2; size:1; signed:0; + field:unsigned char common_preempt_count; offset:3; size:1; signed:0; + field:int common_pid; offset:4; size:4; signed:1; + field:int common_padding; offset:8; size:4; signed:1; + + field:unsigned long __probe_ip; offset:12; size:4; signed:0; + field:u32 arg1; offset:16; size:4; signed:0; + field:u32 arg2; offset:20; size:4; signed:0; + + print fmt: "(%lx) arg1=%lx arg2=%lx", REC->__probe_ip, REC->arg1, REC->arg2 Right after definition, each event is disabled by default. For tracing these events, you need to enable it by: diff --git a/arch/Kconfig b/arch/Kconfig index 0f8f968015e..2880abf8a26 100644 --- a/arch/Kconfig +++ b/arch/Kconfig @@ -78,7 +78,7 @@ config OPTPROBES config UPROBES bool "Transparent user-space probes (EXPERIMENTAL)" - depends on UPROBE_EVENTS && PERF_EVENTS + depends on UPROBE_EVENT && PERF_EVENTS default n help Uprobes is the user-space counterpart to kprobes: they