tracing/probes: Fix to update dynamic data counter if fetcharg uses it
authorMasami Hiramatsu (Google) <mhiramat@kernel.org>
Tue, 11 Jul 2023 14:15:48 +0000 (23:15 +0900)
committerMasami Hiramatsu (Google) <mhiramat@kernel.org>
Thu, 13 Jul 2023 15:37:00 +0000 (00:37 +0900)
Fix to update dynamic data counter ('dyndata') and max length ('maxlen')
only if the fetcharg uses the dynamic data. Also get out arg->dynamic
from unlikely(). This makes dynamic data address wrong if
process_fetch_insn() returns error on !arg->dynamic case.

Link: https://lore.kernel.org/all/168908494781.123124.8160245359962103684.stgit@devnote2/
Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Link: https://lore.kernel.org/all/20230710233400.5aaf024e@gandalf.local.home/
Fixes: 9178412ddf5a ("tracing: probeevent: Return consumed bytes of dynamic area")
Cc: stable@vger.kernel.org
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
kernel/trace/trace_probe_tmpl.h

index ed9d57c..185da00 100644 (file)
@@ -267,11 +267,13 @@ store_trace_args(void *data, struct trace_probe *tp, void *rec,
                if (unlikely(arg->dynamic))
                        *dl = make_data_loc(maxlen, dyndata - base);
                ret = process_fetch_insn(arg->code, rec, dl, base);
-               if (unlikely(ret < 0 && arg->dynamic)) {
-                       *dl = make_data_loc(0, dyndata - base);
-               } else {
-                       dyndata += ret;
-                       maxlen -= ret;
+               if (arg->dynamic) {
+                       if (unlikely(ret < 0)) {
+                               *dl = make_data_loc(0, dyndata - base);
+                       } else {
+                               dyndata += ret;
+                               maxlen -= ret;
+                       }
                }
        }
 }