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Diffstat (limited to 'Documentation/trace/uprobetracer.rst')
| -rw-r--r-- | Documentation/trace/uprobetracer.rst | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/Documentation/trace/uprobetracer.rst b/Documentation/trace/uprobetracer.rst index 4346e23e3ae7..6e75a6c5a2c8 100644 --- a/Documentation/trace/uprobetracer.rst +++ b/Documentation/trace/uprobetracer.rst @@ -42,16 +42,18 @@ Synopsis of uprobe_tracer @+OFFSET : Fetch memory at OFFSET (OFFSET from same file as PATH) $stackN : Fetch Nth entry of stack (N >= 0) $stack : Fetch stack address. - $retval : Fetch return value.(*) + $retval : Fetch return value.(\*1) $comm : Fetch current task comm. - +|-offs(FETCHARG) : Fetch memory at FETCHARG +|- offs address.(**) + +|-[u]OFFS(FETCHARG) : Fetch memory at FETCHARG +|- OFFS address.(\*2)(\*3) NAME=FETCHARG : Set NAME as the argument name of FETCHARG. FETCHARG:TYPE : Set TYPE as the type of FETCHARG. Currently, basic types (u8/u16/u32/u64/s8/s16/s32/s64), hexadecimal types (x8/x16/x32/x64), "string" and bitfield are supported. - (*) only for return probe. - (**) this is useful for fetching a field of data structures. + (\*1) only for return probe. + (\*2) this is useful for fetching a field of data structures. + (\*3) Unlike kprobe event, "u" prefix will just be ignored, becuse uprobe + events can access only user-space memory. Types ----- @@ -152,10 +154,15 @@ events, you need to enable it by:: # echo 1 > events/uprobes/enable -Lets disable the event after sleeping for some time. +Lets start tracing, sleep for some time and stop tracing. :: + # echo 1 > tracing_on # sleep 20 + # echo 0 > tracing_on + +Also, you can disable the event by:: + # echo 0 > events/uprobes/enable And you can see the traced information via /sys/kernel/debug/tracing/trace. |