linux-kernel - [PATCH 2/2] ubifs: Remove ui_mutex in ubifs_xattr_get and change

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <20210531125210.1173922-3-chengzhihao1@huawei.com>
Date:   Mon, 31 May 2021 20:52:10 +0800
From:   Zhihao Cheng <chengzhihao1@...wei.com>
To:     <richard@....at>, <yangds.fnst@...fujitsu.com>,
        <s.hauer@...gutronix.de>
CC:     <yi.zhang@...wei.com>, <houtao1@...wei.com>, <yukuai3@...wei.com>,
        <chengzhihao1@...wei.com>, <linux-mtd@...ts.infradead.org>,
        <linux-kernel@...r.kernel.org>
Subject: [PATCH 2/2] ubifs: Remove ui_mutex in ubifs_xattr_get and change_xattr

Since ubifs_xattr_get and ubifs_xattr_set cannot being executed
parallelly after importing @host_ui->xattr_sem, now we can remove
ui_mutex imported by commit ab92a20bce3b4c2 ("ubifs: make
ubifs_[get|set]xattr atomic").

@xattr_size, @xattr_names and @xattr_cnt can't be out of protection
by @host_ui->mutex yet, they are sill accesed in other places, such as
pack_inode() called by ubifs_write_inode() triggered by page-writeback.

Signed-off-by: Zhihao Cheng <chengzhihao1@...wei.com>
---
 fs/ubifs/xattr.c | 4 ----
 1 file changed, 4 deletions(-)

diff --git a/fs/ubifs/xattr.c b/fs/ubifs/xattr.c
index 1fce27e9b769..e4f193eae4b2 100644
--- a/fs/ubifs/xattr.c
+++ b/fs/ubifs/xattr.c
@@ -208,13 +208,11 @@ static int change_xattr(struct ubifs_info *c, struct inode *host,
 		err = -ENOMEM;
 		goto out_free;
 	}
-	mutex_lock(&ui->ui_mutex);
 	kfree(ui->data);
 	ui->data = buf;
 	inode->i_size = ui->ui_size = size;
 	old_size = ui->data_len;
 	ui->data_len = size;
-	mutex_unlock(&ui->ui_mutex);
 
 	mutex_lock(&host_ui->ui_mutex);
 	host->i_ctime = current_time(host);
@@ -362,7 +360,6 @@ ssize_t ubifs_xattr_get(struct inode *host, const char *name, void *buf,
 	ubifs_assert(c, inode->i_size == ui->data_len);
 	ubifs_assert(c, ubifs_inode(host)->xattr_size > ui->data_len);
 
-	mutex_lock(&ui->ui_mutex);
 	if (buf) {
 		/* If @buf is %NULL we are supposed to return the length */
 		if (ui->data_len > size) {
@@ -375,7 +372,6 @@ ssize_t ubifs_xattr_get(struct inode *host, const char *name, void *buf,
 	err = ui->data_len;
 
 out_iput:
-	mutex_unlock(&ui->ui_mutex);
 	iput(inode);
 out_cleanup:
 	up_read(&ubifs_inode(host)->xattr_sem);
-- 
2.25.4