Messages in this thread | | | Date | Thu, 28 Feb 2008 12:04:10 -0800 (PST) | From | Davide Libenzi <> | Subject | Re: [PATCH/RFC 1/2] anon-inodes: Remove fd_install() from anon_inode_getfd() |
| |
On Wed, 27 Feb 2008, Roland Dreier wrote:
> > http://git.kernel.org/?p=linux/kernel/git/viro/vfs-2.6.git;a=commit;h=49be4f8114e6ff0efdab10ebba2493fb67bc3034 > > Actually, looking closer at the kvm changes here, I think that > create_vcpu_fd() needs the same treatment as kvm_dev_ioctl_create_vm() > gets in the patch because of the race I mentioned in the changelog > for my patch: otherwise kvm_vcpu_release() could drop the last > reference to vcpu->kvm->filp before the get_file() gets an extra > reference. > > I'm beginning to think that moving the fd_install() out of > anon_inode_getfd() really is worth it to make a safer interface.
If we let the caller call fd_install(), then it may be messed up WRT cleanup (fd, file, inode). How about removing the inode pointer handout altogether, and *doing* fd_install() inside anon_inode_getfd() like:
if (pfile != NULL) { get_file(file); *pfile = file; } fd_install(fd, file);
In this way, if the caller want the file* back, he gets the reference bumped before fd_install().
- Davide
| |