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authorMasami Hiramatsu <mhiramat@redhat.com>2009-10-07 18:27:48 -0400
committerFrederic Weisbecker <fweisbec@gmail.com>2009-10-12 19:24:05 +0200
commit99329c44f28a1b7ac83beebfb4319e612042e319 (patch)
treedd28ca39b7a0b9130cc513f313255a38a8cea204 /Documentation/trace
parent405b2651e4bedf8d3932b64cad649b4d26b067f5 (diff)
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tracing/kprobes: Remove '$ra' special variable
Remove '$ra' (return address) because it is already shown at the head of each entry. Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Arnaldo Carvalho de Melo <acme@redhat.com> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Mike Galbraith <efault@gmx.de> Cc: Paul Mackerras <paulus@samba.org> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Christoph Hellwig <hch@infradead.org> Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com> Cc: Jim Keniston <jkenisto@us.ibm.com> Cc: Frank Ch. Eigler <fche@redhat.com> LKML-Reference: <20091007222748.1684.12711.stgit@dhcp-100-2-132.bos.redhat.com> Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Diffstat (limited to 'Documentation/trace')
-rw-r--r--Documentation/trace/kprobetrace.txt13
1 files changed, 6 insertions, 7 deletions
diff --git a/Documentation/trace/kprobetrace.txt b/Documentation/trace/kprobetrace.txt
index 33f5318..4208253 100644
--- a/Documentation/trace/kprobetrace.txt
+++ b/Documentation/trace/kprobetrace.txt
@@ -1,4 +1,4 @@
- Kprobe-based Event Tracer
+ Kprobe-based Event Tracer
=========================
Documentation is written by Masami Hiramatsu
@@ -42,7 +42,6 @@ Synopsis of kprobe_events
$sa : Fetch stack address.
$aN : Fetch function argument. (N >= 0)(*)
$rv : Fetch return value.(**)
- $ra : Fetch return address.(**)
+|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(***)
NAME=FETCHARG: Set NAME as the argument name of FETCHARG.
@@ -91,10 +90,10 @@ as below.
1st to 4th arguments as "myprobe" event. As this example shows, users can
choose more familiar names for each arguments.
- echo r:myretprobe do_sys_open $rv $ra >> /sys/kernel/debug/tracing/kprobe_events
+ echo r:myretprobe do_sys_open $rv >> /sys/kernel/debug/tracing/kprobe_events
This sets a kretprobe on the return point of do_sys_open() function with
-recording return value and return address as "myretprobe" event.
+recording return value as "myretprobe" event.
You can see the format of these events via
/sys/kernel/debug/tracing/events/kprobes/<EVENT>/format.
@@ -138,11 +137,11 @@ events, you need to enable it.
# TASK-PID CPU# TIMESTAMP FUNCTION
# | | | | |
<...>-1447 [001] 1038282.286875: myprobe: (do_sys_open+0x0/0xd6) dfd=3 filename=7fffd1ec4440 flags=8000 mode=0
- <...>-1447 [001] 1038282.286878: myretprobe: (sys_openat+0xc/0xe <- do_sys_open) $rv=fffffffffffffffe $ra=ffffffff81367a3a
+ <...>-1447 [001] 1038282.286878: myretprobe: (sys_openat+0xc/0xe <- do_sys_open) $rv=fffffffffffffffe
<...>-1447 [001] 1038282.286885: myprobe: (do_sys_open+0x0/0xd6) dfd=ffffff9c filename=40413c flags=8000 mode=1b6
- <...>-1447 [001] 1038282.286915: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 $ra=ffffffff81367a3a
+ <...>-1447 [001] 1038282.286915: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3
<...>-1447 [001] 1038282.286969: myprobe: (do_sys_open+0x0/0xd6) dfd=ffffff9c filename=4041c6 flags=98800 mode=10
- <...>-1447 [001] 1038282.286976: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3 $ra=ffffffff81367a3a
+ <...>-1447 [001] 1038282.286976: myretprobe: (sys_open+0x1b/0x1d <- do_sys_open) $rv=3
Each line shows when the kernel hits an event, and <- SYMBOL means kernel