From: Tzvetomir Stoyanov (VMware) tz.stoyanov@gmail.com
[ 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 --- 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 753fc536525d3..d2370cdb4c1d6 100644 --- a/kernel/trace/trace_eprobe.c +++ b/kernel/trace/trace_eprobe.c @@ -743,6 +743,7 @@ 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)) @@ -766,12 +767,25 @@ 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