Hello Tzvetomir Stoyanov (VMware),
This is a semi-automatic email about new static checker warnings.
The patch 7491e2c44278: "tracing: Add a probe that attaches to trace
events" from Aug 19, 2021, leads to the following Smatch complaint:
kernel/trace/trace_eprobe.c:674 enable_trace_eprobe()
warn: variable dereferenced before check 'file' (see line 664)
kernel/trace/trace_eprobe.c
638 static int enable_trace_eprobe(struct trace_event_call *call,
639 struct trace_event_file *file)
640 {
641 struct trace_probe *pos, *tp;
642 struct trace_eprobe *ep;
643 bool enabled;
644 int ret = 0;
645
646 tp = trace_probe_primary_from_call(call);
647 if (WARN_ON_ONCE(!tp))
648 return -ENODEV;
649 enabled = trace_probe_is_enabled(tp);
650
651 /* This also changes "enabled" state */
652 if (file) {
653 ret = trace_probe_add_file(tp, file);
654 if (ret)
655 return ret;
656 } else
657 trace_probe_set_flag(tp, TP_FLAG_PROFILE);
658
659 if (enabled)
660 return 0;
661
662 list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
663 ep = container_of(pos, struct trace_eprobe, tp);
664 ret = enable_eprobe(ep, file);
^^^^
"file" is dereferenced here.
665 if (ret)
666 break;
667 enabled = true;
668 }
669
670 if (ret) {
671 /* Failed to enable one of them. Roll back all */
672 if (enabled)
673 disable_eprobe(ep, file->tr);
674 if (file)
^^^^
This check is too late.
675 trace_probe_remove_file(tp, file);
676 else
regards,
dan carpenter
