On Mon, Apr 06, 2015 at 05:30:35PM +0900, Sergey Senozhatsky wrote:
> On (03/15/15 01:00), Josh Triplett wrote:
> [..]
> > +
> > +/* Handle the CLONE_FD case for copy_process. */
> > +int clonefd_do_clone(u64 clone_flags, struct task_struct *p,
> > + struct clone4_args *args, struct clonefd_setup *setup)
> > +{
> > + int flags;
> > + struct file *file;
> > + int fd;
> > +
> > + p->clonefd = !!(clone_flags & CLONE_FD);
> > + if (!p->clonefd)
> > + return 0;
> > +
> > + if (args->clonefd_flags & ~(O_CLOEXEC | O_NONBLOCK))
> > + return -EINVAL;
> > +
> > + init_waitqueue_head(&p->clonefd_wqh);
> > +
> > + get_task_struct(p);
> > + flags = O_RDONLY | FMODE_ATOMIC_POS | args->clonefd_flags;
> > + file = anon_inode_getfile("[process]", &clonefd_fops, p, flags);
> > + if (IS_ERR(file)) {
> > + put_task_struct(p);
> > + return PTR_ERR(file);
> > + }
> > +
> > + fd = get_unused_fd_flags(flags);
> > + if (fd < 0) {
>
> + put_task_struct(p); ?
No, once anon_inode_getfile has succeeded, the file owns the reference
to the task_struct, so fput(file) will call the release function which
calls put_task_struct. Only the failure case for anon_inode_getfile
needs to call put_task_struct directly.
> > + fput(file);
> > + return fd;
> > + }
- Josh Triplett
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