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Commit ec83db0f authored by Srikar Dronamraju's avatar Srikar Dronamraju Committed by Ingo Molnar
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tracing: Fix kconfig warning due to a typo 



Commit f3f096cf ("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: default avatarStephen Boyd <sboyd@codeaurora.org>
Reported-by: default avatarIngo Molnar <mingo@kernel.org>
Signed-off-by: default avatarSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
Cc: Anton Arapov <anton@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20120508111126.21004.38285.sendpatchset@srdronam.in.ibm.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent f3f096cf

Documentation/trace/uprobetracer.txt

+20 −2
Original line number Diff line number Diff line
@@ -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:

arch/Kconfig

+1 −1
Original line number Diff line number Diff line
@@ -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