3.8-stable review patch. If anyone has any objections, please let me know.
------------------ From: Ming Lei <ming....@canonical.com> commit 991f76f837bf22c5bb07261cfd86525a0a96650c upstream. While readdir() is running, lseek() may set filp->f_pos as zero, then may leave filp->private_data pointing to one sysfs_dirent object without holding its reference counter, so the sysfs_dirent object may be used after free in next readdir(). This patch holds inode->i_mutex to avoid the problem since the lock is always held in readdir path. Reported-by: Dave Jones <da...@redhat.com> Tested-by: Sasha Levin <levinsasha...@gmail.com> Signed-off-by: Ming Lei <ming....@canonical.com> Signed-off-by: Greg Kroah-Hartman <gre...@linuxfoundation.org> --- fs/sysfs/dir.c | 13 ++++++++++++- 1 file changed, 12 insertions(+), 1 deletion(-) --- a/fs/sysfs/dir.c +++ b/fs/sysfs/dir.c @@ -1058,10 +1058,21 @@ static int sysfs_readdir(struct file * f return 0; } +static loff_t sysfs_dir_llseek(struct file *file, loff_t offset, int whence) +{ + struct inode *inode = file->f_path.dentry->d_inode; + loff_t ret; + + mutex_lock(&inode->i_mutex); + ret = generic_file_llseek(file, offset, whence); + mutex_unlock(&inode->i_mutex); + + return ret; +} const struct file_operations sysfs_dir_operations = { .read = generic_read_dir, .readdir = sysfs_readdir, .release = sysfs_dir_release, - .llseek = generic_file_llseek, + .llseek = sysfs_dir_llseek, }; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/