From: Artem Savkov asavkov@redhat.com
If enable_trace_kprobe fails to enable the probe in enable_k(ret)probe it returns an error, but does not unset the tp flags it set previously. This results in a probe being considered enabled and failures like being unable to remove the probe through kprobe_events file since probes_open() expects every probe to be disabled.
Link: http://lkml.kernel.org/r/20180725102826.8300-1-asavkov@redhat.com Link: http://lkml.kernel.org/r/20180725142038.4765-1-asavkov@redhat.com
Cc: Ingo Molnar mingo@redhat.com Cc: stable@vger.kernel.org Fixes: 41a7dd420c57 ("tracing/kprobes: Support ftrace_event_file base multibuffer") Acked-by: Masami Hiramatsu mhiramat@kernel.org Reviewed-by: Josh Poimboeuf jpoimboe@redhat.com Signed-off-by: Artem Savkov asavkov@redhat.com Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org --- kernel/trace/trace_kprobe.c | 13 +++++++++++-- 1 file changed, 11 insertions(+), 2 deletions(-)
diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c index 21f718472942..27ace4513c43 100644 --- a/kernel/trace/trace_kprobe.c +++ b/kernel/trace/trace_kprobe.c @@ -400,11 +400,10 @@ static struct trace_kprobe *find_trace_kprobe(const char *event, static int enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file) { + struct event_file_link *link; int ret = 0;
if (file) { - struct event_file_link *link; - link = kmalloc(sizeof(*link), GFP_KERNEL); if (!link) { ret = -ENOMEM; @@ -424,6 +423,16 @@ enable_trace_kprobe(struct trace_kprobe *tk, struct trace_event_file *file) else ret = enable_kprobe(&tk->rp.kp); } + + if (ret) { + if (file) { + list_del_rcu(&link->list); + kfree(link); + tk->tp.flags &= ~TP_FLAG_TRACE; + } else { + tk->tp.flags &= ~TP_FLAG_PROFILE; + } + } out: return ret; }