From 0a01f2cc390e10633a54f72c608cc3fe19a50c3d Mon Sep 17 00:00:00 2001 From: "Eric W. Biederman" Date: Wed, 1 Aug 2012 10:33:47 -0700 Subject: 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 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" Signed-off-by: "Eric W. Biederman" --- fs/proc/root.c | 5 ----- 1 file changed, 5 deletions(-) (limited to 'fs/proc/root.c') 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) return; - err = pid_ns_prepare_proc(&init_pid_ns); - if (err) { - unregister_filesystem(&proc_fs_type); - return; - } proc_self_init(); proc_symlink("mounts", NULL, "self/mounts"); -- cgit v1.2.3