tracing: Show real address for trace event arguments
To help debugging kernel, show real address for trace event arguments
in tracefs/trace{,pipe} instead of hashed pointer value.
Since ftrace human-readable format uses vsprintf(), all %p are
translated to hash values instead of pointer address.
However, when debugging the kernel, raw address value gives a
hint when comparing with the memory mapping in the kernel.
(Those are sometimes used with crash log, which is not hashed too)
So converting %p with %px when calling trace_seq_printf().
Moreover, this is not improving the security because the tracefs
can be used only by root user and the raw address values are readable
from tracefs/percpu/cpu*/trace_pipe_raw file.
Link: https://lkml.kernel.org/r/160277370703.29307.5134475491761971203.stgit@devnote2
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Signed-off-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
diff --git a/kernel/trace/trace_output.c b/kernel/trace/trace_output.c
index 92b1575..61255ba 100644
--- a/kernel/trace/trace_output.c
+++ b/kernel/trace/trace_output.c
@@ -312,13 +312,23 @@ int trace_raw_output_prep(struct trace_iterator *iter,
}
EXPORT_SYMBOL(trace_raw_output_prep);
+void trace_event_printf(struct trace_iterator *iter, const char *fmt, ...)
+{
+ va_list ap;
+
+ va_start(ap, fmt);
+ trace_seq_vprintf(&iter->seq, trace_event_format(iter, fmt), ap);
+ va_end(ap);
+}
+EXPORT_SYMBOL(trace_event_printf);
+
static int trace_output_raw(struct trace_iterator *iter, char *name,
char *fmt, va_list ap)
{
struct trace_seq *s = &iter->seq;
trace_seq_printf(s, "%s: ", name);
- trace_seq_vprintf(s, fmt, ap);
+ trace_seq_vprintf(s, trace_event_format(iter, fmt), ap);
return trace_handle_return(s);
}