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debugfs: Fix filesystem reference counting on debugfs_remove() failure

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When __debugfs_remove() fails (because simple_rmdir() fails e.g. when a
directory is not empty), we must not decrement use count of the filesystem
as nothing was in fact deleted.

This fixes use after free caused by debugfs in some cases.

Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Jan Kara 2011-02-07 15:00:27 +01:00 committed by Greg Kroah-Hartman
parent b38360a284
commit 25d41d8455
1 changed files with 7 additions and 4 deletions
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11
fs/debugfs/inode.c
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@ -307,7 +307,7 @@ struct dentry *debugfs_create_symlink(const char *name, struct dentry *parent,
}
EXPORT_SYMBOL_GPL(debugfs_create_symlink);
static void __debugfs_remove(struct dentry *dentry, struct dentry *parent)
static int __debugfs_remove(struct dentry *dentry, struct dentry *parent)
{
int ret = 0;
@ -330,6 +330,7 @@ static void __debugfs_remove(struct dentry *dentry, struct dentry *parent)
dput(dentry);
}
}
return ret;
}
/**
@ -348,7 +349,8 @@ static void __debugfs_remove(struct dentry *dentry, struct dentry *parent)
void debugfs_remove(struct dentry *dentry)
{
struct dentry *parent;
int ret;
if (!dentry)
return;
@ -357,9 +359,10 @@ void debugfs_remove(struct dentry *dentry)
return;
mutex_lock(&parent->d_inode->i_mutex);
__debugfs_remove(dentry, parent);
ret = __debugfs_remove(dentry, parent);
mutex_unlock(&parent->d_inode->i_mutex);
simple_release_fs(&debugfs_mount, &debugfs_mount_count);
if (!ret)
simple_release_fs(&debugfs_mount, &debugfs_mount_count);
}
EXPORT_SYMBOL_GPL(debugfs_remove);