diff options
| author | Eric W. Biederman <ebiederm@xmission.com> | 2012-08-01 10:33:47 -0700 |
|---|---|---|
| committer | Eric W. Biederman <ebiederm@xmission.com> | 2012-11-19 05:59:10 -0800 |
| commit | 0a01f2cc390e10633a54f72c608cc3fe19a50c3d (patch) | |
| tree | e713a1c45b5ce125a5d33b61d528cd45264d47a7 /fs | |
| parent | 17cf22c33e1f1b5e435469c84e43872579497653 (diff) | |
| download | linux-0a01f2cc390e10633a54f72c608cc3fe19a50c3d.tar.bz2 | |
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')
| -rw-r--r-- | fs/proc/base.c | 4 | ||||
| -rw-r--r-- | fs/proc/root.c | 5 |
2 files changed, 0 insertions, 9 deletions
diff --git a/fs/proc/base.c b/fs/proc/base.c index 6177fc238fdb..7621dc51cff8 100644 --- a/fs/proc/base.c +++ b/fs/proc/base.c @@ -2590,10 +2590,6 @@ void proc_flush_task(struct task_struct *task) proc_flush_task_mnt(upid->ns->proc_mnt, upid->nr, tgid->numbers[i].nr); } - - upid = &pid->numbers[pid->level]; - if (upid->nr == 1) - pid_ns_release_proc(upid->ns); } static struct dentry *proc_pid_instantiate(struct inode *dir, diff --git a/fs/proc/root.c b/fs/proc/root.c index fc1609321a78..f2f251158d35 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"); |