[PATCH v20] tracing: Fix kconfig warning due to a typo

From: Srikar Dronamraju
Date: Tue May 08 2012 - 07:22:50 EST

From: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>

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
uprobetracer documentation.

Also add sample format of a uprobe event in the uprobetracer
documentation as suggested by Masami Hiramatsu.

Reported-by: Stephen Boyd <sboyd@xxxxxxxxxxxxxx>
Reported-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx>
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 eae40a0..24ce682 100644
--- a/Documentation/trace/uprobetracer.txt
+++ b/Documentation/trace/uprobetracer.txt
@@ -5,7 +5,7 @@
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 9e2fbb5..c160d92 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -78,7 +78,7 @@ config OPTPROBES

config UPROBES
bool "Transparent user-space probes (EXPERIMENTAL)"
default n
Uprobes is the user-space counterpart to kprobes: they

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