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kernel/trace: Fix cleanup logic of enable_trace_eprobe 

The enable_trace_eprobe() function enables all event probes, attached
to given trace probe. If an error occurs in enabling one of the event
probes, all others should be roll backed. There is a bug in that roll
back logic - instead of all event probes, only the failed one is
disabled.

Link: https://lore.kernel.org/all/20230703042853.1427493-1-tz.stoyanov@gmail.com/

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Fixes: 7491e2c442 ("tracing: Add a probe that attaches to trace events")
Signed-off-by: Tzvetomir Stoyanov (VMware) <tz.stoyanov@gmail.com>
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>
Signed-off-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
This commit is contained in:
Tzvetomir Stoyanov (VMware) 2023-07-03 07:28:53 +03:00 committed by Masami Hiramatsu (Google)
parent 5f81018753
commit cf0a624dc7
1 changed files with 16 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

18
kernel/trace/trace_eprobe.c
View File

@ -675,6 +675,7 @@ static int enable_trace_eprobe(struct trace_event_call *call,
struct trace_eprobe *ep;
bool enabled;
int ret = 0;
int cnt = 0;
tp = trace_probe_primary_from_call(call);
if (WARN_ON_ONCE(!tp))
@ -698,12 +699,25 @@ static int enable_trace_eprobe(struct trace_event_call *call,
if (ret)
break;
enabled = true;
cnt++;
}
if (ret) {
/* Failed to enable one of them. Roll back all */
if (enabled)
disable_eprobe(ep, file->tr);
if (enabled) {
/*
* It's a bug if one failed for something other than memory
* not being available but another eprobe succeeded.
*/
WARN_ON_ONCE(ret != -ENOMEM);
list_for_each_entry(pos, trace_probe_probe_list(tp), list) {
ep = container_of(pos, struct trace_eprobe, tp);
disable_eprobe(ep, file->tr);
if (!--cnt)
break;
}
}
if (file)
trace_probe_remove_file(tp, file);
else