uprobes: shift put_uprobe() from delete_uprobe() to uprobe_unregister()

Kill the extra get_uprobe() + put_uprobe() in uprobe_unregister() and
move the possibly final put_uprobe() from delete_uprobe() to its only
caller, uprobe_unregister().

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Jiri Olsa <jolsa@kernel.org>
Acked-by: Andrii Nakryiko <andrii@kernel.org>
Acked-by: "Masami Hiramatsu (Google)" <mhiramat@kernel.org>
Link: https://lore.kernel.org/r/20240801132749.GA8817@redhat.com

diff --git a/kernel/events/uprobes.c b/kernel/events/uprobes.c
index 175058b209a96f741d658b185f5b830f7370be24..30348f13d4a72794b820342a3acf5afdf2db3048 100644 (file)
--- a/kernel/events/uprobes.c
+++ b/kernel/events/uprobes.c
@@ -939,7 +939,6 @@ static void delete_uprobe(struct uprobe *uprobe)
        rb_erase(&uprobe->rb_node, &uprobes_tree);
        write_unlock(&uprobes_treelock);
        RB_CLEAR_NODE(&uprobe->rb_node); /* for uprobe_is_active() */
-       put_uprobe(uprobe);
 }
 
 struct map_info {
@@ -1094,7 +1093,6 @@ void uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *uc)
 {
        int err;
 
-       get_uprobe(uprobe);
        down_write(&uprobe->register_rwsem);
        if (WARN_ON(!consumer_del(uprobe, uc)))
                err = -ENOENT;
@@ -1102,10 +1100,16 @@ void uprobe_unregister(struct uprobe *uprobe, struct uprobe_consumer *uc)
                err = register_for_each_vma(uprobe, NULL);
 
        /* TODO : cant unregister? schedule a worker thread */
-       if (!err && !uprobe->consumers)
-               delete_uprobe(uprobe);
+       if (!err) {
+               if (!uprobe->consumers)
+                       delete_uprobe(uprobe);
+               else
+                       err = -EBUSY;
+       }
        up_write(&uprobe->register_rwsem);
-       put_uprobe(uprobe);
+
+       if (!err)
+               put_uprobe(uprobe);
 }
 EXPORT_SYMBOL_GPL(uprobe_unregister);