From nobody Wed Dec 17 23:15:41 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 25EC6C61D85 for ; Tue, 21 Nov 2023 23:11:04 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234894AbjKUXLF (ORCPT ); Tue, 21 Nov 2023 18:11:05 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54954 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229527AbjKUXLA (ORCPT ); Tue, 21 Nov 2023 18:11:00 -0500 Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B1ED110C for ; Tue, 21 Nov 2023 15:10:56 -0800 (PST) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 58720C433C9; Tue, 21 Nov 2023 23:10:56 +0000 (UTC) Received: from rostedt by gandalf with local (Exim 4.97-RC3) (envelope-from ) id 1r5Ztg-00000002dDc-27wd; Tue, 21 Nov 2023 18:11:12 -0500 Message-ID: <20231121231112.373501894@goodmis.org> User-Agent: quilt/0.67 Date: Tue, 21 Nov 2023 18:10:04 -0500 From: Steven Rostedt To: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org Cc: Masami Hiramatsu , Mark Rutland , Andrew Morton Subject: [PATCH 1/4] eventfs: Use GFP_NOFS for allocation when eventfs_mutex is held References: <20231121231003.516999942@goodmis.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: "Steven Rostedt (Google)" If memory reclaim happens, it can reclaim file system pages. The file system pages from eventfs may take the eventfs_mutex on reclaim. This means that allocation while holding the eventfs_mutex must not call into filesystem reclaim. A lockdep splat uncovered this. Fixes: 28e12c09f5aa0 ("eventfs: Save ownership and mode") Fixes: 5790b1fb3d672 ("eventfs: Remove eventfs_file and just use eventfs_in= ode") Reported-by: Mark Rutland Signed-off-by: Steven Rostedt (Google) --- fs/tracefs/event_inode.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index 3eb6c622a74d..56d192f0ead8 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -95,7 +95,7 @@ static int eventfs_set_attr(struct mnt_idmap *idmap, stru= ct dentry *dentry, if (!(dentry->d_inode->i_mode & S_IFDIR)) { if (!ei->entry_attrs) { ei->entry_attrs =3D kzalloc(sizeof(*ei->entry_attrs) * ei->nr_entries, - GFP_KERNEL); + GFP_NOFS); if (!ei->entry_attrs) { ret =3D -ENOMEM; goto out; @@ -627,7 +627,7 @@ static int add_dentries(struct dentry ***dentries, stru= ct dentry *d, int cnt) { struct dentry **tmp; =20 - tmp =3D krealloc(*dentries, sizeof(d) * (cnt + 2), GFP_KERNEL); + tmp =3D krealloc(*dentries, sizeof(d) * (cnt + 2), GFP_NOFS); if (!tmp) return -1; tmp[cnt] =3D d; --=20 2.42.0