linux-kernel - [PATCH 4.18 147/197] btrfs: use device_list

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: <20180913131847.435319298@linuxfoundation.org>
Date:   Thu, 13 Sep 2018 15:31:36 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Anand Jain <anand.jain@...cle.com>,
        David Sterba <dsterba@...e.com>,
        Sasha Levin <alexander.levin@...rosoft.com>
Subject: [PATCH 4.18 147/197] btrfs: use device_list_mutex when removing stale devices

4.18-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Anand Jain <anand.jain@...cle.com>

[ Upstream commit 7bcb8164ad9435068d9bc3b83b8a002c64d63ff6 ]

btrfs_free_stale_devices() finds a stale (not opened) device matching
path in the fs_uuid list. We are already under uuid_mutex so when we
check for each fs_devices, hold the device_list_mutex too.

Signed-off-by: Anand Jain <anand.jain@...cle.com>
Reviewed-by: David Sterba <dsterba@...e.com>
Signed-off-by: David Sterba <dsterba@...e.com>
Signed-off-by: Sasha Levin <alexander.levin@...rosoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>
---
 fs/btrfs/volumes.c |   25 +++++++++++++++----------
 1 file changed, 15 insertions(+), 10 deletions(-)

--- a/fs/btrfs/volumes.c
+++ b/fs/btrfs/volumes.c
@@ -640,8 +640,11 @@ static void btrfs_free_stale_devices(con
 	struct btrfs_device *device, *tmp_device;
 
 	list_for_each_entry_safe(fs_devices, tmp_fs_devices, &fs_uuids, fs_list) {
-		if (fs_devices->opened)
+		mutex_lock(&fs_devices->device_list_mutex);
+		if (fs_devices->opened) {
+			mutex_unlock(&fs_devices->device_list_mutex);
 			continue;
+		}
 
 		list_for_each_entry_safe(device, tmp_device,
 					 &fs_devices->devices, dev_list) {
@@ -661,16 +664,18 @@ static void btrfs_free_stale_devices(con
 				continue;
 
 			/* delete the stale device */
-			if (fs_devices->num_devices == 1) {
-				btrfs_sysfs_remove_fsid(fs_devices);
-				list_del(&fs_devices->fs_list);
-				free_fs_devices(fs_devices);
+			fs_devices->num_devices--;
+			list_del(&device->dev_list);
+			btrfs_free_device(device);
+
+			if (fs_devices->num_devices == 0)
 				break;
-			} else {
-				fs_devices->num_devices--;
-				list_del(&device->dev_list);
-				btrfs_free_device(device);
-			}
+		}
+		mutex_unlock(&fs_devices->device_list_mutex);
+		if (fs_devices->num_devices == 0) {
+			btrfs_sysfs_remove_fsid(fs_devices);
+			list_del(&fs_devices->fs_list);
+			free_fs_devices(fs_devices);
 		}
 	}
 }