1 files changed, 32 insertions, 18 deletions

diff --git a/kernel/trace/trace_kprobe.c b/kernel/trace/trace_kprobe.c
index 7ed6976493c8..243f6834d026 100644
--- a/kernel/trace/trace_kprobe.c
+++ b/kernel/trace/trace_kprobe.c
@@ -95,7 +95,7 @@ static __kprobes bool trace_probe_is_on_module(struct trace_probe *tp)
 }
 
 static int register_probe_event(struct trace_probe *tp);
-static void unregister_probe_event(struct trace_probe *tp);
+static int unregister_probe_event(struct trace_probe *tp);
 
 static DEFINE_MUTEX(probe_lock);
 static LIST_HEAD(probe_list);
@@ -243,11 +243,11 @@ find_event_file_link(struct trace_probe *tp, struct ftrace_event_file *file)
 static int
 disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
 {
+        struct event_file_link *link = NULL;
+        int wait = 0;
         int ret = 0;
 
         if (file) {
-                struct event_file_link *link;
-
                 link = find_event_file_link(tp, file);
                 if (!link) {
                         ret = -EINVAL;
@@ -255,10 +255,7 @@ disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
                 }
 
                 list_del_rcu(&link->list);
-                /* synchronize with kprobe_trace_func/kretprobe_trace_func */
-                synchronize_sched();
-                kfree(link);
-
+                wait = 1;
                 if (!list_empty(&tp->files))
                         goto out;
 
@@ -271,8 +268,22 @@ disable_trace_probe(struct trace_probe *tp, struct ftrace_event_file *file)
                         disable_kretprobe(&tp->rp);
                 else
                         disable_kprobe(&tp->rp.kp);
+                wait = 1;
         }
  out:
+        if (wait) {
+                /*
+                 * Synchronize with kprobe_trace_func/kretprobe_trace_func
+                 * to ensure disabled (all running handlers are finished).
+                 * This is not only for kfree(), but also the caller,
+                 * trace_remove_event_call() supposes it for releasing
+                 * event_call related objects, which will be accessed in
+                 * the kprobe_trace_func/kretprobe_trace_func.
+                 */
+                synchronize_sched();
+                kfree(link);    /* Ignored if link == NULL */
+        }
+
         return ret;
 }
 
@@ -340,9 +351,12 @@ static int unregister_trace_probe(struct trace_probe *tp)
         if (trace_probe_is_enabled(tp))
                 return -EBUSY;
 
+        /* Will fail if probe is being used by ftrace or perf */
+        if (unregister_probe_event(tp))
+                return -EBUSY;
+
         __unregister_trace_probe(tp);
         list_del(&tp->list);
-        unregister_probe_event(tp);
 
         return 0;
 }
@@ -621,7 +635,9 @@ static int release_all_trace_probes(void)
         /* TODO: Use batch unregistration */
         while (!list_empty(&probe_list)) {
                 tp = list_entry(probe_list.next, struct trace_probe, list);
-                unregister_trace_probe(tp);
+                ret = unregister_trace_probe(tp);
+                if (ret)
+                        goto end;
                 free_trace_probe(tp);
         }
 
@@ -1087,9 +1103,6 @@ kprobe_perf_func(struct trace_probe *tp, struct pt_regs *regs)
         __size = sizeof(*entry) + tp->size + dsize;
         size = ALIGN(__size + sizeof(u32), sizeof(u64));
         size -= sizeof(u32);
-        if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-                     "profile buffer not large enough"))
-                return;
 
         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
         if (!entry)
@@ -1120,9 +1133,6 @@ kretprobe_perf_func(struct trace_probe *tp, struct kretprobe_instance *ri,
         __size = sizeof(*entry) + tp->size + dsize;
         size = ALIGN(__size + sizeof(u32), sizeof(u64));
         size -= sizeof(u32);
-        if (WARN_ONCE(size > PERF_MAX_TRACE_SIZE,
-                     "profile buffer not large enough"))
-                return;
 
         entry = perf_trace_buf_prepare(size, call->event.type, regs, &rctx);
         if (!entry)
@@ -1242,11 +1252,15 @@ static int register_probe_event(struct trace_probe *tp)
         return ret;
 }
 
-static void unregister_probe_event(struct trace_probe *tp)
+static int unregister_probe_event(struct trace_probe *tp)
 {
+        int ret;
+
         /* tp->event is unregistered in trace_remove_event_call() */
-        trace_remove_event_call(&tp->call);
-        kfree(tp->call.print_fmt);
+        ret = trace_remove_event_call(&tp->call);
+        if (!ret)
+                kfree(tp->call.print_fmt);
+        return ret;
 }
 
 /* Make a debugfs interface for controlling probe points */