We could use setns to join the current ns, which did a lot of unnecessary work. This patch will check this senario and return 0 directly.
Signed-off-by: Chen Hanxiao <[email protected]> --- kernel/nsproxy.c | 28 ++++++++++++++++++++++++++++ 1 file changed, 28 insertions(+) diff --git a/kernel/nsproxy.c b/kernel/nsproxy.c index ef42d0a..66eea63 100644 --- a/kernel/nsproxy.c +++ b/kernel/nsproxy.c @@ -236,6 +236,34 @@ SYSCALL_DEFINE2(setns, int, fd, int, nstype) ops = ei->ns_ops; if (nstype && (ops->type != nstype)) goto out; + switch (ops->type) { + case CLONE_NEWIPC: + if (ei->ns == tsk->nsproxy->ipc_ns) + return 0; + break; + case CLONE_NEWNET: + if (ei->ns == tsk->nsproxy->net_ns) + return 0; + break; + case CLONE_NEWNS: + if (ei->ns == tsk->nsproxy->mnt_ns) + return 0; + break; + case CLONE_NEWPID: + if (ei->ns == tsk->nsproxy->pid_ns_for_children) + return 0; + break; + case CLONE_NEWUSER: + if (ei->ns == current_user_ns()) + return 0; + break; + case CLONE_NEWUTS: + if (ei->ns == tsk->nsproxy->uts_ns) + return 0; + break; + default: + goto out; + } new_nsproxy = create_new_namespaces(0, tsk, current_user_ns(), tsk->fs); if (IS_ERR(new_nsproxy)) { -- 1.9.0 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
