From: "Tzvetomir Stoyanov (VMware)" <tz.stoyanov@gmail.com>
Date: Mon, 3 Jul 2023 07:28:53 +0300
Subject: [PATCH] kernel/trace: Fix cleanup logic of enable_trace_eprobe
References: bsc#1012628
Patch-mainline: 6.4.5
Git-commit: cf0a624dc706c306294c14e6b3e7694702f25191
[ Upstream commit cf0a624dc706c306294c14e6b3e7694702f25191 ]
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: 7491e2c44278 ("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>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
kernel/trace/trace_eprobe.c | 18 ++++++++++++++++--
1 file changed, 16 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace_eprobe.c b/kernel/trace/trace_eprobe.c
index 67e85497..3f04f0ff 100644
--- a/kernel/trace/trace_eprobe.c
+++ b/kernel/trace/trace_eprobe.c
@@ -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
--
2.35.3