user/sven/linux.git/kernel/pid.c, branch v2.6.26.8

pids: introduce change_pid() helper

2008-04-30T15:29:48Z

Based on Eric W. Biederman's idea. Without tasklist_lock held task_session()/task_pgrp() can return NULL if the caller races with setprgp()/setsid() which does detach_pid() + attach_pid(). This can happen even if task == current. Intoduce the new helper, change_pid(), which should be used instead. This way the caller always sees the special pid != NULL, either old or new. Also change the prototype of attach_pid(), it always returns 0 and nobody check the returned value. Signed-off-by: Oleg Nesterov Cc: "Eric W. Biederman" Cc: Pavel Emelyanov Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pids: de_thread: don't clear session/pgrp pids for the old leader

2008-04-30T15:29:48Z

Based on Eric W. Biederman's idea. Unless task == current, without tasklist_lock held task_session()/task_pgrp() can return NULL if the caller races with de_thread() which switches the group leader. Change transfer_pid() to not clear old->pids[type].pid for the old leader. This means that its .pid can point to "nowhere", but this is already true for sub-threads, and the old leader is not group_leader() any longer. IOW, with or without this change we can't trust task's special pids unless it is the group leader. With this change the following code rcu_read_lock(); task = find_task_by_xxx(); do_something(task_pgrp(task), task_session(task)); rcu_read_unlock(); can't race with exec and hit the NULL pid. Signed-off-by: Oleg Nesterov Cc: "Eric W. Biederman" Cc: Pavel Emelyanov Cc: Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Deprecate find_task_by_pid()

2008-04-30T15:29:48Z

There are some places that are known to operate on tasks' global pids only: * the rest_init() call (called on boot) * the kgdb's getthread * the create_kthread() (since the kthread is run in init ns) So use the find_task_by_pid_ns(..., &init_pid_ns) there and schedule the find_task_by_pid for removal. [sukadev@us.ibm.com: Fix warning in kernel/pid.c] Signed-off-by: Pavel Emelyanov Cc: "Eric W. Biederman" Signed-off-by: Sukadev Bhattiprolu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

free_pidmap: turn it into free_pidmap(struct upid *)

2008-04-30T15:29:48Z

The callers of free_pidmap() pass 2 members of "struct upid", we can just pass "struct upid *" instead. Shaves off 10 bytes from pid.o. Also, simplify the alloc_pid's "out_free:" error path a little bit. This way it looks more clear which subset of pid->numbers[] we are freeing. Signed-off-by: Oleg Nesterov Cc: Pavel Emelyanov Cc: "Eric W. Biederman" Cc :Roland McGrath Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel: remove fastcall in kernel/*

2008-02-08T17:22:31Z

[akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Harvey Harrison Acked-by: Ingo Molnar Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pid: Extend/Fix pid_vnr

2008-02-08T17:22:27Z

pid_vnr returns the user space pid with respect to the pid namespace the struct pid was allocated in. What we want before we return a pid to user space is the user space pid with respect to the pid namespace of current. pid_vnr is a very nice optimization but because it isn't quite what we want it is easy to use pid_vnr at times when we aren't certain the struct pid was allocated in our pid namespace. Currently this describes at least tiocgpgrp and tiocgsid in ttyio.c the parent process reported in the core dumps and the parent process in get_signal_to_deliver. So unless the performance impact is huge having an interface that does what we want instead of always what we want should be much more reliable and much less error prone. Signed-off-by: Eric W. Biederman Cc: Oleg Nesterov Acked-by: Pavel Emelyanov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

namespaces: cleanup the code managed with PID_NS option

2008-02-08T17:22:23Z

Just like with the user namespaces, move the namespace management code into the separate .c file and mark the (already existing) PID_NS option as "depend on NAMESPACES" [akpm@linux-foundation.org: coding-style fixes] Signed-off-by: Pavel Emelyanov Acked-by: Serge Hallyn Cc: Cedric Le Goater Cc: "Eric W. Biederman" Cc: Herbert Poetzl Cc: Kirill Korotaev Cc: Sukadev Bhattiprolu Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

gfs2: make gfs2_glock.gl_owner_pid be a struct pid *

2008-02-07T16:42:06Z

The gl_owner_pid field is used to get the lock owning task by its pid, so make it in a proper manner, i.e. by using the struct pid pointer and pid_task() function. The pid_task() becomes exported for the gfs2 module. Signed-off-by: Pavel Emelyanov Cc: "Eric W. Biederman" Acked-by: Steven Whitehouse Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

pidns: Place under CONFIG_EXPERIMENTAL

2007-11-15T02:45:43Z

This is my trivial patch to swat innumerable little bugs with a single blow. After some intensive review (my apologies for not having gotten to this sooner) what we have looks like a good base to build on with the current pid namespace code but it is not complete, and it is still much to simple to find issues where the kernel does the wrong thing outside of the initial pid namespace. Until the dust settles and we are certain we have the ABI and the implementation is as correct as humanly possible let's keep process ID namespaces behind CONFIG_EXPERIMENTAL. Allowing us the option of fixing any ABI or other bugs we find as long as they are minor. Allowing users of the kernel to avoid those bugs simply by ensuring their kernel does not have support for multiple pid namespaces. [akpm@linux-foundation.org: coding-style cleanups] Signed-off-by: Eric W. Biederman Cc: Cedric Le Goater Cc: Adrian Bunk Cc: Jeremy Fitzhardinge Cc: Kir Kolyshkin Cc: Kirill Korotaev Cc: Pavel Emelyanov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

Uninline the task_xid_nr_ns() calls

2007-10-19T18:53:41Z

Since these are expanded into call to pid_nr_ns() anyway, it's OK to move the whole routine out-of-line. This is a cheap way to save ~100 bytes from vmlinux. Together with the previous two patches, it saves half-a-kilo from the vmlinux. Un-inline other (currently inlined) functions must be done with additional performance testing. Signed-off-by: Pavel Emelyanov Cc: Sukadev Bhattiprolu Cc: Oleg Nesterov Cc: Paul Menage Cc: "Eric W. Biederman" Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds