path: root/fs/proc/root.c
diff options
authorEric W. Biederman <ebiederm@xmission.com>2012-08-01 10:33:47 -0700
committerEric W. Biederman <ebiederm@xmission.com>2012-11-19 05:59:10 -0800
commit0a01f2cc390e10633a54f72c608cc3fe19a50c3d (patch)
treee713a1c45b5ce125a5d33b61d528cd45264d47a7 /fs/proc/root.c
parent17cf22c33e1f1b5e435469c84e43872579497653 (diff)
pidns: Make the pidns proc mount/umount logic obvious.
Track the number of pids in the proc hash table. When the number of pids goes to 0 schedule work to unmount the kernel mount of proc. Move the mount of proc into alloc_pid when we allocate the pid for init. Remove the surprising calls of pid_ns_release proc in fork and proc_flush_task. Those code paths really shouldn't know about proc namespace implementation details and people have demonstrated several times that finding and understanding those code paths is difficult and non-obvious. Because of the call path detach pid is alwasy called with the rtnl_lock held free_pid is not allowed to sleep, so the work to unmounting proc is moved to a work queue. This has the side benefit of not blocking the entire world waiting for the unnecessary rcu_barrier in deactivate_locked_super. In the process of making the code clear and obvious this fixes a bug reported by Gao feng <gaofeng@cn.fujitsu.com> where we would leak a mount of proc during clone(CLONE_NEWPID|CLONE_NEWNET) if copy_pid_ns succeeded and copy_net_ns failed. Acked-by: "Serge E. Hallyn" <serge@hallyn.com> Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Diffstat (limited to 'fs/proc/root.c')
1 files changed, 0 insertions, 5 deletions
diff --git a/fs/proc/root.c b/fs/proc/root.c
index fc1609321a7..f2f251158d3 100644
--- a/fs/proc/root.c
+++ b/fs/proc/root.c
@@ -155,11 +155,6 @@ void __init proc_root_init(void)
err = register_filesystem(&proc_fs_type);
if (err)
- err = pid_ns_prepare_proc(&init_pid_ns);
- if (err) {
- unregister_filesystem(&proc_fs_type);
- return;
- }
proc_symlink("mounts", NULL, "self/mounts");