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| author | slyich@gmail.com <slyich@gmail.com> | 2011-11-07 16:08:01 -0500 |
|---|---|---|
| committer | Chris Mason <chris.mason@oracle.com> | 2011-11-07 16:08:01 -0500 |
| commit | 45ea6095c8f0d6caad5658306416a5d254f1205e (patch) | |
| tree | 84c25fabfb4b0a8e4fdbc16b5d29ba75ebf7a0ce | |
| parent | 7c7e82a77fe3d89ae50824aa7c897454675eb4c4 (diff) | |
| download | regulator-45ea6095c8f0d6caad5658306416a5d254f1205e.tar.gz | |
btrfs: fix double-free 'tree_root' in 'btrfs_mount()'
On error path 'tree_root' is treed in 'free_fs_info()'.
No need to free it explicitely. Noticed by SLUB in debug mode:
Complete reproducer under usermode linux (discovered on real
machine):
bdev=/dev/ubda
btr_root=/btr
/mkfs.btrfs $bdev
mount $bdev $btr_root
mkdir $btr_root/subvols/
cd $btr_root/subvols/
/btrfs su cr foo
/btrfs su cr bar
mount $bdev -osubvol=subvols/foo $btr_root/subvols/bar
umount $btr_root/subvols/bar
which gives
device fsid 4d55aa28-45b1-474b-b4ec-da912322195e devid 1 transid 7 /dev/ubda
=============================================================================
BUG kmalloc-2048: Object already free
-----------------------------------------------------------------------------
INFO: Allocated in btrfs_mount+0x389/0x7f0 age=0 cpu=0 pid=277
INFO: Freed in btrfs_mount+0x51c/0x7f0 age=0 cpu=0 pid=277
INFO: Slab 0x0000000062886200 objects=15 used=9 fp=0x0000000070b4d2d0 flags=0x4081
INFO: Object 0x0000000070b4d2d0 @offset=21200 fp=0x0000000070b4a968
...
Call Trace:
70b31948: [<6008c522>] print_trailer+0xe2/0x130
70b31978: [<6008c5aa>] object_err+0x3a/0x50
70b319a8: [<6008e242>] free_debug_processing+0x142/0x2a0
70b319e0: [<600ebf6f>] btrfs_mount+0x55f/0x7f0
70b319f8: [<6008e5c1>] __slab_free+0x221/0x2d0
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>
Cc: Arne Jansen <sensille@gmx.net>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: David Sterba <dsterba@suse.cz>
Signed-off-by: Chris Mason <chris.mason@oracle.com>
| -rw-r--r-- | fs/btrfs/super.c | 8 |
1 files changed, 5 insertions, 3 deletions
diff --git a/fs/btrfs/super.c b/fs/btrfs/super.c index 57080dffdfc6f1..dcd5aef6b6148a 100644 --- a/fs/btrfs/super.c +++ b/fs/btrfs/super.c @@ -933,8 +933,12 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags, * then open_ctree will properly initialize everything later. */ fs_info = kzalloc(sizeof(struct btrfs_fs_info), GFP_NOFS); + if (!fs_info) { + error = -ENOMEM; + goto error_close_devices; + } tree_root = kzalloc(sizeof(struct btrfs_root), GFP_NOFS); - if (!fs_info || !tree_root) { + if (!tree_root) { error = -ENOMEM; goto error_close_devices; } @@ -964,7 +968,6 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags, btrfs_close_devices(fs_devices); free_fs_info(fs_info); - kfree(tree_root); } else { char b[BDEVNAME_SIZE]; @@ -992,7 +995,6 @@ static struct dentry *btrfs_mount(struct file_system_type *fs_type, int flags, error_close_devices: btrfs_close_devices(fs_devices); free_fs_info(fs_info); - kfree(tree_root); return ERR_PTR(error); } |