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-rw-r--r--Documentation/trace/uprobetracer.txt22
1 files changed, 20 insertions, 2 deletions
diff --git a/Documentation/trace/uprobetracer.txt b/Documentation/trace/uprobetracer.txt
index eae40a003eec..24ce6823a09e 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: