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| author | Masami Hiramatsu <mhiramat@kernel.org> | 2019-06-19 18:08:37 +0300 |
|---|---|---|
| committer | Steven Rostedt (VMware) <rostedt@goodmis.org> | 2019-08-31 19:19:39 +0300 |
| commit | a42e3c4de9642d5de524a0a48a7ce96872662dca (patch) | |
| tree | 75303cede44b02307d5d504bf4a0d1ce84dcee24 /kernel/trace/trace_kprobe.c | |
| parent | 6218bf9f4d2942e88d97b60abc8c2ca0532e41a8 (diff) | |
| download | linux-a42e3c4de9642d5de524a0a48a7ce96872662dca.tar.xz | |
tracing/probe: Add immediate string parameter support
Add immediate string parameter (\"string") support to
probe events. This allows you to specify an immediate
(or dummy) parameter instead of fetching a string from
memory.
This feature looks odd, but imagine that you put a probe
on a code to trace some string data. If the code is
compiled into 2 instructions and 1 instruction has a
string on memory but other has no string since it is
optimized out. In that case, you can not fold those into
one event, even if ftrace supported multiple probes on
one event. With this feature, you can set a dummy string
like foo=\"(optimized)":string instead of something
like foo=+0(+0(%bp)):string.
Link: http://lkml.kernel.org/r/156095691687.28024.13372712423865047991.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Diffstat (limited to 'kernel/trace/trace_kprobe.c')
| -rw-r--r-- | kernel/trace/trace_kprobe.c | 3 |
1 files changed, 3 insertions, 0 deletions
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 18c4175b6585..7579c53bb053 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -1083,6 +1083,9 @@ retry: case FETCH_OP_COMM: val = (unsigned long)current->comm; break; + case FETCH_OP_DATA: + val = (unsigned long)code->data; + break; #ifdef CONFIG_HAVE_FUNCTION_ARG_ACCESS_API case FETCH_OP_ARG: val = regs_get_kernel_argument(regs, code->param); |