From patchwork Sun Dec 10 21:35:34 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Beau Belgrave X-Patchwork-Id: 13486503 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux.microsoft.com header.i=@linux.microsoft.com header.b="Q0yqQ06D" Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id D7EE7CF; Sun, 10 Dec 2023 13:35:39 -0800 (PST) Received: from localhost.localdomain (unknown [4.155.48.117]) by linux.microsoft.com (Postfix) with ESMTPSA id 0B1F620B74C0; Sun, 10 Dec 2023 13:35:39 -0800 (PST) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 0B1F620B74C0 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1702244139; bh=AwLPxkWSQ+xItqIkFFnflTbsJwcL70eHM305+He6/Pg=; h=From:To:Cc:Subject:Date:From; b=Q0yqQ06DL6j6eJXGiMYqLMRzH0Z35EwyGtwfYeQo39pIavtQQswP9U9W+Y2C4mnK5 4DOQl4iBwB/Fdjj1Twp+REAOorZvSpve6dVXFD+7rnWCyPFshu2X+bO0PC3bT60Jod +u8XHr4jdJl+or4ylxmDlOSB7qLan3taIGygsXug= From: Beau Belgrave To: rostedt@goodmis.org Cc: linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: [PATCH] eventfs: Fix events beyond NAME_MAX blocking tasks Date: Sun, 10 Dec 2023 21:35:34 +0000 Message-Id: <20231210213534.497-1-beaub@linux.microsoft.com> X-Mailer: git-send-email 2.34.1 Precedence: bulk X-Mailing-List: linux-trace-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Eventfs uses simple_lookup(), however, it will fail if the name of the entry is beyond NAME_MAX length. When this error is encountered, eventfs still tries to create dentries instead of skipping the dentry creation. When the dentry is attempted to be created in this state d_wait_lookup() will loop forever, waiting for the lookup to be removed. Fix eventfs to return the error in simple_lookup() back to the caller instead of continuing to try to create the dentry. Fixes: 63940449555e ("eventfs: Implement eventfs lookup, read, open functions") Link: https://lore.kernel.org/linux-trace-kernel/20231208183601.GA46-beaub@linux.microsoft.com/ Signed-off-by: Beau Belgrave --- Please note the fixes tag is the first add of simple_lookup logic, there have been other changes beyond that may be a better fit to targetting. fs/tracefs/event_inode.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/fs/tracefs/event_inode.c b/fs/tracefs/event_inode.c index f8a594a50ae6..d2c06ba26db4 100644 --- a/fs/tracefs/event_inode.c +++ b/fs/tracefs/event_inode.c @@ -561,6 +561,8 @@ static struct dentry *eventfs_root_lookup(struct inode *dir, if (strcmp(ei_child->name, name) != 0) continue; ret = simple_lookup(dir, dentry, flags); + if (IS_ERR(ret)) + goto out; create_dir_dentry(ei, ei_child, ei_dentry, true); created = true; break; @@ -583,6 +585,8 @@ static struct dentry *eventfs_root_lookup(struct inode *dir, if (r <= 0) continue; ret = simple_lookup(dir, dentry, flags); + if (IS_ERR(ret)) + goto out; create_file_dentry(ei, i, ei_dentry, name, mode, cdata, fops, true); break;