Re: PATCH -mm] fix create_new_namespaces() return value

[Badari Pulavarty <pbadari@us.ibm.com>]

Cedric Le Goater wrote:

>The following patch modifies create_new_namespaces() to also use the 
>errors returned by the copy_*_ns routines and not to systematically 
>return ENOMEM.
>

In my initial version, I did same. It doesn't work :(

copy_*_ns() routines doesn't return any errors. All they return is NULL 
in case of a
failure + with the exception of copy_mnt_ns, there are no other failure 
cases.
So, there is no way to find out why the copy_*_ns() routines failed from 
create_new_namespaces().
If you really really want to do this, change all copy_*_ns() routines to 
returns meaningful
errors instead of NULL.

>
>
>Signed-off-by: Cedric Le Goater <clg@fr.ibm.com>
>Cc: Serge E. Hallyn <serue@us.ibm.com>
>Cc: Badari Pulavarty <pbadari@us.ibm.com>
>Cc: Pavel Emelianov <xemul@openvz.org>
>Cc: Herbert Poetzl <herbert@13thfloor.at>
>Cc: Eric W. Biederman <ebiederm@xmission.com>
>---
> kernel/nsproxy.c |   23 +++++++++++++++++------
> 1 file changed, 17 insertions(+), 6 deletions(-)
>
>Index: 2.6.22-rc4-mm2/kernel/nsproxy.c
>===================================================================
>--- 2.6.22-rc4-mm2.orig/kernel/nsproxy.c
>+++ 2.6.22-rc4-mm2/kernel/nsproxy.c
>@@ -58,30 +58,41 @@ static struct nsproxy *create_new_namesp
> 			struct fs_struct *new_fs)
> {
> 	struct nsproxy *new_nsp;
>+	int err;
>
> 	new_nsp = clone_nsproxy(tsk->nsproxy);
> 	if (!new_nsp)
> 		return ERR_PTR(-ENOMEM);
>
> 	new_nsp->mnt_ns = copy_mnt_ns(flags, tsk->nsproxy->mnt_ns, new_fs);
>-	if (IS_ERR(new_nsp->mnt_ns))
>+	if (IS_ERR(new_nsp->mnt_ns)) {
>+		err = PTR_ERR(new_nsp->mnt_ns);
> 		goto out_ns;
>+	}
>
> 	new_nsp->uts_ns = copy_utsname(flags, tsk->nsproxy->uts_ns);
>-	if (IS_ERR(new_nsp->uts_ns))
>+	if (IS_ERR(new_nsp->uts_ns)) {
>+		err = PTR_ERR(new_nsp->uts_ns);
> 		goto out_uts;
>+	}
>
> 	new_nsp->ipc_ns = copy_ipcs(flags, tsk->nsproxy->ipc_ns);
>-	if (IS_ERR(new_nsp->ipc_ns))
>+	if (IS_ERR(new_nsp->ipc_ns)) {
>+		err = PTR_ERR(new_nsp->ipc_ns);
> 		goto out_ipc;
>+	}
>
> 	new_nsp->pid_ns = copy_pid_ns(flags, tsk->nsproxy->pid_ns);
>-	if (IS_ERR(new_nsp->pid_ns))
>+	if (IS_ERR(new_nsp->pid_ns)) {
>+		err = PTR_ERR(new_nsp->pid_ns);
> 		goto out_pid;
>+	}
>
> 	new_nsp->user_ns = copy_user_ns(flags, tsk->nsproxy->user_ns);
>-	if (IS_ERR(new_nsp->user_ns))
>+	if (IS_ERR(new_nsp->user_ns)) {
>+		err = PTR_ERR(new_nsp->user_ns);
>
Hmm.. copy_user_ns() ? I don't see this in rc4-mm2.

Thanks,
Badari