linux-kernel - [v6.6][PATCH 14/57] eventfs: Remove extra dget() in eventfs_create_events

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Message-ID: <20240206120948.657072999@rostedt.homelinux.com>
Date: Tue, 06 Feb 2024 07:09:19 -0500
From: Steven Rostedt <rostedt@...dmis.org>
To: linux-kernel@...r.kernel.org,
 stable@...r.kernel.org
Cc: Linus Torvalds <torvalds@...ux-foundation.org>,
 Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
 Sasha Levin <sashal@...nel.org>,
 Masami Hiramatsu <mhiramat@...nel.org>,
 Mark Rutland <mark.rutland@....com>,
 Mathieu Desnoyers <mathieu.desnoyers@...icios.com>
Subject: [v6.6][PATCH 14/57] eventfs: Remove extra dget() in eventfs_create_events_dir()

From: "Steven Rostedt (Google)" <rostedt@...dmis.org>

The creation of the top events directory does a dget() at the end of the
creation in eventfs_create_events_dir() with a comment saying the final
dput() will happen when it is removed. The problem is that a dget() is
already done on the dentry when it was created with tracefs_start_creating()!
The dget() now just causes a memory leak of that dentry.

Remove the extra dget() as the final dput() in the deletion of the events
directory actually matches the one in tracefs_start_creating().

Link: https://lore.kernel.org/linux-trace-kernel/20231031124229.4f2e3fa1@gandalf.local.home

Cc: Masami Hiramatsu <mhiramat@...nel.org>
Cc: Mark Rutland <mark.rutland@....com>
Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_inode")
Signed-off-by: Steven Rostedt (Google) <rostedt@...dmis.org>
(cherry picked from commit 77bc4d4921bd3497678ba8e7f4e480de35692f05)
---
 fs/tracefs/event_inode.c | 3 ---
 1 file changed, 3 deletions(-)

diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c
index 4d2da7480e5f..5536860eb2ff 100644
--- a/fs/tracefs/event_inode.c
+++ b/fs/tracefs/event_inode.c
@@ -774,9 +774,6 @@ struct eventfs_inode *eventfs_create_events_dir(const char *name, struct dentry
 	fsnotify_mkdir(dentry->d_parent->d_inode, dentry);
 	tracefs_end_creating(dentry);
 
-	/* Will call dput when the directory is removed */
-	dget(dentry);
-
 	return ei;
 
  fail:
-- 
2.43.0