Reorder source so that all the code and data for each interface is together.
Signed-off-by: NMatt Mackall <mpm@selenic.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This puts all the clear_refs code where it belongs and probably lets things
compile on MMU-less systems as well.
Signed-off-by: NMatt Mackall <mpm@selenic.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: David Rientjes <rientjes@google.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This pulls the shared map display code out of show_map and puts it in
show_smap where it belongs.
Signed-off-by: NMatt Mackall <mpm@selenic.com>
Cc: Jeremy Fitzhardinge <jeremy@goop.org>
Acked-by: NDavid Rientjes <rientjes@google.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use the generic pagewalker for smaps and clear_refs
Signed-off-by: NMatt Mackall <mpm@selenic.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The "proportional set size" (PSS) of a process is the count of pages it has
in memory, where each page is divided by the number of processes sharing
it.  So if a process has 1000 pages all to itself, and 1000 shared with one
other process, its PSS will be 1500.

               - lwn.net: "ELC: How much memory are applications really using?"

The PSS proposed by Matt Mackall is a very nice metic for measuring an
process's memory footprint.  So collect and export it via
/proc/<pid>/smaps.

Matt Mackall's pagemap/kpagemap and John Berthels's exmap can also do the
job.  They are comprehensive tools.  But for PSS, let's do it in the simple
way.

Cc: John Berthels <jjberthels@gmail.com>
Cc: Bernardo Innocenti <bernie@codewiz.org>
Cc: Padraig Brady <P@draigBrady.com>
Cc: Denys Vlasenko <vda.linux@googlemail.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: NMatt Mackall <mpm@selenic.com>
Signed-off-by: NFengguang Wu <wfg@mail.ustc.edu.cn>
Cc: Hugh Dickins <hugh@veritas.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Checking if an address is a vmalloc address is done in a couple of places.
Define a common version in mm.h and replace the other checks.

Again the include structures suck.  The definition of VMALLOC_START and
VMALLOC_END is not available in vmalloc.h since highmem.c cannot be included
there.
Signed-off-by: NChristoph Lameter <clameter@sgi.com>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

all callers pass something->audit_context
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

cat /proc/net/atm/arp causes the NULL pointer dereference in the
get_proc_net+0xc/0x3a. This happens as proc_get_net believes that the
parent proc dir entry contains struct net.

Fix this assumption for "net/atm" case.

The problem is introduced by the commit c0097b07abf5f92ab135d024dd41bd2aada1512f
from Eric W. Biederman/Daniel Lezcano.
Signed-off-by: NDenis V. Lunev <den@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NDenis V. Lunev <den@openvz.org>
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

LatencyTOP kernel infrastructure; it measures latencies in the
scheduler and tracks it system wide and per process.
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Commit 84427eae (remove task_ppid_nr_ns)
moved the task_tgid_nr_ns(task->real_parent) outside of lock_task_sighand().
This is wrong, ->real_parent could be freed/reused.

Both ->parent/real_parent point to nothing after __exit_signal() because
we remove the child from ->children list, and thus the child can't be
reparented when its parent exits.

rcu_read_lock() protects ->parent/real_parent, but _only_ if we know it was
valid before we take rcu lock.

Revert this part of the patch.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

task_ppid_nr_ns is called in three places.  One of these should never
have called it.  In the other two, using it broke the existing
semantics.  This was presumably accidental.  If the function had not
been there, it would have been much more obvious to the eye that those
patches were changing the behavior.  We don't need this function.

In task_state, the pid of the ptracer is not the ppid of the ptracer.

In do_task_stat, ppid is the tgid of the real_parent, not its pid.
I also moved the call outside of lock_task_sighand, since it doesn't
need it.

In sys_getppid, ppid is the tgid of the real_parent, not its pid.
Signed-off-by: NRoland McGrath <roland@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Contents of /proc/*/maps is sensitive and may become sensitive after
open() (e.g.  if target originally shares our ->mm and later does exec
on suid-root binary).

Check at read() (actually, ->start() of iterator) time that mm_struct
we'd grabbed and locked is
 - still the ->mm of target
 - equal to reader's ->mm or the target is ptracable by reader.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Acked-by: NRik van Riel <riel@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Both SLUB and SLAB really did almost exactly the same thing for
/proc/slabinfo setup, using duplicate code and per-allocator #ifdef's.

This just creates a common CONFIG_SLABINFO that is enabled by both SLUB
and SLAB, and shares all the setup code.  Maybe SLOB will want this some
day too.
Reviewed-by: NPekka Enberg <penberg@cs.helsinki.fi>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

We need to register slabinfo to procfs when CONFIG_SLUB is enabled to
make the file actually visible to user-space.
Signed-off-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Ultimately to implement /proc perfectly we need an implementation of
d_revalidate because files and directories can be removed behind the back
of the VFS, and d_revalidate is the only way we can let the VFS know that
this has happened.

Unfortunately the linux VFS can not cope with anything in the path to a
mount point going away.  So a proper d_revalidate method that calls d_drop
also needs to call have_submounts which is moderately expensive, so you
really don't want a d_revalidate method that unconditionally calls it, but
instead only calls it when the backing object has really gone away.

proc generic entries only disappear on module_unload (when not counting the
fledgling network namespace) so it is quite rare that we actually encounter
that case and has not actually caused us real world trouble yet.

So until we get a proper test for keeping dentries in the dcache fix the
current d_revalidate method by completely removing it.  This returns us to
the current status quo.

So with CONFIG_NETNS=n things should look as they have always looked.

For CONFIG_NETNS=y things work most of the time but there are a few rare
corner cases that don't behave properly.  As the network namespace is
barely present in 2.6.24 this should not be a problem.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: "Denis V. Lunev" <den@openvz.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>

Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>

Creating PDEs with refcount 0 and "deleted" flag has problems (see below).
Switch to usual scheme:
* PDE is created with refcount 1
* every de_get does +1
* every de_put() and remove_proc_entry() do -1
* once refcount reaches 0, PDE is freed.

This elegantly fixes at least two following races (both observed) without
introducing new locks, without abusing old locks, without spreading
lock_kernel():

1) PDE leak

remove_proc_entry			de_put
-----------------			------
			[refcnt = 1]
if (atomic_read(&de->count) == 0)
					if (atomic_dec_and_test(&de->count))
						if (de->deleted)
							/* also not taken! */
							free_proc_entry(de);
else
	de->deleted = 1;
		[refcount=0, deleted=1]

2) use after free

remove_proc_entry			de_put
-----------------			------
			[refcnt = 1]

					if (atomic_dec_and_test(&de->count))
if (atomic_read(&de->count) == 0)
	free_proc_entry(de);
						/* boom! */
						if (de->deleted)
							free_proc_entry(de);

BUG: unable to handle kernel paging request at virtual address 6b6b6b6b
printing eip: c10acdda *pdpt = 00000000338f8001 *pde = 0000000000000000
Oops: 0000 [#1] PREEMPT SMP
Modules linked in: af_packet ipv6 cpufreq_ondemand loop serio_raw psmouse k8temp hwmon sr_mod cdrom
Pid: 23161, comm: cat Not tainted (2.6.24-rc2-8c086340 #4)
EIP: 0060:[<c10acdda>] EFLAGS: 00210097 CPU: 1
EIP is at strnlen+0x6/0x18
EAX: 6b6b6b6b EBX: 6b6b6b6b ECX: 6b6b6b6b EDX: fffffffe
ESI: c128fa3b EDI: f380bf34 EBP: ffffffff ESP: f380be44
 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process cat (pid: 23161, ti=f380b000 task=f38f2570 task.ti=f380b000)
Stack: c10ac4f0 00000278 c12ce000 f43cd2a8 00000163 00000000 7da86067 00000400
       c128fa20 00896b18 f38325a8 c128fe20 ffffffff 00000000 c11f291e 00000400
       f75be300 c128fa20 f769c9a0 c10ac779 f380bf34 f7bfee70 c1018e6b f380bf34
Call Trace:
 [<c10ac4f0>] vsnprintf+0x2ad/0x49b
 [<c10ac779>] vscnprintf+0x14/0x1f
 [<c1018e6b>] vprintk+0xc5/0x2f9
 [<c10379f1>] handle_fasteoi_irq+0x0/0xab
 [<c1004f44>] do_IRQ+0x9f/0xb7
 [<c117db3b>] preempt_schedule_irq+0x3f/0x5b
 [<c100264e>] need_resched+0x1f/0x21
 [<c10190ba>] printk+0x1b/0x1f
 [<c107c8ad>] de_put+0x3d/0x50
 [<c107c8f8>] proc_delete_inode+0x38/0x41
 [<c107c8c0>] proc_delete_inode+0x0/0x41
 [<c1066298>] generic_delete_inode+0x5e/0xc6
 [<c1065aa9>] iput+0x60/0x62
 [<c1063c8e>] d_kill+0x2d/0x46
 [<c1063fa9>] dput+0xdc/0xe4
 [<c10571a1>] __fput+0xb0/0xcd
 [<c1054e49>] filp_close+0x48/0x4f
 [<c1055ee9>] sys_close+0x67/0xa5
 [<c10026b6>] sysenter_past_esp+0x5f/0x85
=======================
Code: c9 74 0c f2 ae 74 05 bf 01 00 00 00 4f 89 fa 5f 89 d0 c3 85 c9 57 89 c7 89 d0 74 05 f2 ae 75 01 4f 89 f8 5f c3 89 c1 89 c8 eb 06 <80> 38 00 74 07 40 4a 83 fa ff 75 f4 29 c8 c3 90 90 90 57 83 c9
EIP: [<c10acdda>] strnlen+0x6/0x18 SS:ESP 0068:f380be44

Also, remove broken usage of ->deleted from reiserfs: if sget() succeeds,
module is already pinned and remove_proc_entry() can't happen => nobody
can mark PDE deleted.

Dummy proc root in netns code is not marked with refcount 1. AFAICS, we
never get it, it's just for proper /proc/net removal. I double checked
CLONE_NETNS continues to work.

Patch survives many hours of modprobe/rmmod/cat loops without new bugs
which can be attributed to refcounting.
Signed-off-by: NAlexey Dobriyan <adobriyan@sw.ru>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Well I clearly goofed when I added the initial network namespace support
for /proc/net.  Currently things work but there are odd details visible to
user space, even when we have a single network namespace.

Since we do not cache proc_dir_entry dentries at the moment we can just
modify ->lookup to return a different directory inode depending on the
network namespace of the process looking at /proc/net, replacing the
current technique of using a magic and fragile follow_link method.

To accomplish that this patch:
- introduces a shadow_proc method to allow different dentries to
  be returned from proc_lookup.
- Removes the old /proc/net follow_link magic
- Fixes a weakness in our not caching of proc generic dentries.

As shadow_proc uses a task struct to decided which dentry to return we can
go back later and fix the proc generic caching without modifying any code
that uses the shadow_proc method.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

Oleg noticed that the call of task_pid_nr_ns() in proc_pid_readdir
is racy with respect to tasks exiting.

After a bit of examination it also appears that the call itself
is completely unnecessary.

So to fix the problem this patch modifies next_tgid() to return
both a tgid and the task struct in question.

A structure is introduced to return these values because it is
slightly cleaner and easier to optimize, and the resulting code
is a little shorter.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

proc_kill_inodes() can clear ->i_fop in the middle of vfs_readdir resulting in
NULL dereference during "file->f_op->readdir(file, buf, filler)".

The solution is to remove proc_kill_inodes() completely:

a) we don't have tricky modules implementing their tricky readdir hooks which
   could keeping this revoke from hell.

b) In a situation when module is gone but PDE still alive, standard
   readdir will return only "." and "..", because pde->next was cleared by
   remove_proc_entry().

c) the race proc_kill_inode() destined to prevent is not completely
   fixed, just race window made smaller, because vfs_readdir() is run
   without sb_lock held and without file_list_lock held.  Effectively,
   ->i_fop is cleared at random moment, which can't fix properly anything.

BUG: unable to handle kernel NULL pointer dereference at virtual address 00000018
printing eip: c1061205 *pdpt = 0000000005b22001 *pde = 0000000000000000
Oops: 0000 [#1] PREEMPT SMP
Modules linked in: foo af_packet ipv6 cpufreq_ondemand loop serio_raw sr_mod k8temp cdrom hwmon amd_rng
Pid: 2033, comm: find Not tainted (2.6.24-rc1-b1d08ac0 #2)
EIP: 0060:[<c1061205>] EFLAGS: 00010246 CPU: 0
EIP is at vfs_readdir+0x47/0x74
EAX: c6b6a780 EBX: 00000000 ECX: c1061040 EDX: c5decf94
ESI: c6b6a780 EDI: fffffffe EBP: c9797c54 ESP: c5decf78
 DS: 007b ES: 007b FS: 00d8 GS: 0033 SS: 0068
Process find (pid: 2033, ti=c5dec000 task=c64bba90 task.ti=c5dec000)
Stack: c5decf94 c1061040 fffffff7 0805ffbc 00000000 c6b6a780 c1061295 0805ffbc
       00000000 00000400 00000000 00000004 0805ffbc 4588eff4 c5dec000 c10026ba
       00000004 0805ffbc 00000400 0805ffbc 4588eff4 bfdc6c70 000000dc 0000007b
Call Trace:
 [<c1061040>] filldir64+0x0/0xc5
 [<c1061295>] sys_getdents64+0x63/0xa5
 [<c10026ba>] sysenter_past_esp+0x5f/0x85
 =======================
Code: 49 83 78 18 00 74 43 8d 6b 74 bf fe ff ff ff 89 e8 e8 b8 c0 12 00 f6 83 2c 01 00 00 10 75 22 8b 5e 10 8b 4c 24 04 89 f0 8b 14 24 <ff> 53 18 f6 46 1a 04 89 c7 75 0b 8b 56 0c 8b 46 08 e8 c8 66 00
EIP: [<c1061205>] vfs_readdir+0x47/0x74 SS:ESP 0068:c5decf78

hch: "Nice, getting rid of this is a very good step formwards.
      Unfortunately we have another copy of this junk in
      security/selinux/selinuxfs.c:sel_remove_entries() which would need the
      same treatment."
Signed-off-by: NAlexey Dobriyan <adobriyan@sw.ru>
Acked-by: NChristoph Hellwig <hch@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: James Morris <jmorris@namei.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Srivatsa Vaddagiri noticed occasionally incorrect CPU usage
values in top and tracked it down to stime going below 0 in
task_stime(). Negative values are possible there due to the
sampled nature of stime/utime.

Fix suggested by Balbir Singh.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Tested-by: NSrivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Reviewed-by: NBalbir Singh <balbir@linux.vnet.ibm.com>

Currently we special case when we have only the initial pid namespace.
Unfortunately in doing so the copied case for the other namespaces was
broken so we don't properly flush the thread directories :(

So this patch removes the unnecessary special case (removing a usage of
proc_mnt) and corrects the flushing of the thread directories.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Cc: Al Viro <viro@ftp.linux.org.uk>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Kirill Korotaev <dev@sw.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

It appears we overlooked support for removing generic proc files
when we added support for multiple proc super blocks.  Handle
that now.

[akpm@linux-foundation.org: coding-style cleanups]
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Acked-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Alexey Dobriyan <adobriyan@sw.ru>
Acked-by: NSukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This patch reverts Eric's commit 2b008b0a

It diets .text & .data section of the kernel if CONFIG_NET_NS is not set.
This is safe after list operations cleanup.
Signed-of-by: NDenis V. Lunev <den@openvz.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

There are no more users.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Extend Peter's patch to fix accounting issues, by keeping stime
monotonic too.
Signed-off-by: NBalbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Tested-by: NFrans Pop <elendil@planet.nl>

keep utime/stime monotonic.

cpustats use utime/stime as a ratio against sum_exec_runtime, as a
consequence it can happen - when the ratio changes faster than time
accumulates - that either can be appear to go backwards.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

It is not safe to to place struct pernet_operations in a special section.
We need struct pernet_operations to last until we call unregister_pernet_subsys.
Which doesn't happen until module unload.

So marking struct pernet_operations is a disaster for modules in two ways.
- We discard it before we call the exit method it points to.
- Because I keep struct pernet_operations on a linked list discarding
  it for compiled in code removes elements in the middle of a linked
  list and does horrible things for linked insert.

So this looks safe assuming __exit_refok is not discarded
for modules.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Struct proc_net_ns_ops can become static.
Signed-off-by: NAdrian Bunk <bunk@kernel.org>
Acked-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Fix pointer mismatches in proc_sysctl.c.  The proc_handler() method returns a
size_t through an arg pointer, but is given a pointer to a ssize_t to return
into.
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix mnt_flush_task() misplaced kernel-doc.
Fix typos in some of the doc text.

Warning(linux-2.6.23-git17//fs/proc/base.c:2280): No description found for parameter 'mnt'
Warning(linux-2.6.23-git17//fs/proc/base.c:2280): No description found for parameter 'pid'
Warning(linux-2.6.23-git17//fs/proc/base.c:2280): No description found for parameter 'tgid'
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When removing the explicit task_struct->pid usage I found that
proc_readfd_common() and proc_pident_readdir() get this field, but do not
use it at all.  So this cleanup is a cheap help with the task_struct->pid
isolation.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

tsk->exit_state can only be 0, EXIT_ZOMBIE, or EXIT_DEAD.  A non-zero test
is the same as tsk->exit_state & (EXIT_ZOMBIE | EXIT_DEAD), so just testing
tsk->exit_state is sufficient.
Signed-off-by: NEugene Teo <eugeneteo@kernel.sg>
Cc: Roland McGrath <roland@redhat.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Currently, there exists no method for a process to query the resource
limits of another process.  They can be inferred via some mechanisms but
they cannot be explicitly determined.  Given that this information can be
usefull to know during the debugging of an application, I've written this
patch which exports all of a processes limits via /proc/<pid>/limits.
Signed-off-by: NNeil Horman <nhorman@tuxdriver.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

With pid namespaces this field is now dangerous to use explicitly, so hide
it behind the helpers.

Also the pid and pgrp fields o task_struct and signal_struct are to be
deprecated.  Unfortunately this patch cannot be sent right now as this
leads to tons of warnings, so start isolating them, and deprecate later.

Actually the p->tgid == pid has to be changed to has_group_leader_pid(),
but Oleg pointed out that in case of posix cpu timers this is the same, and
thread_group_leader() is more preferable.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Acked-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This is the largest patch in the set. Make all (I hope) the places where
the pid is shown to or get from user operate on the virtual pids.

The idea is:
 - all in-kernel data structures must store either struct pid itself
   or the pid's global nr, obtained with pid_nr() call;
 - when seeking the task from kernel code with the stored id one
   should use find_task_by_pid() call that works with global pids;
 - when showing pid's numerical value to the user the virtual one
   should be used, but however when one shows task's pid outside this
   task's namespace the global one is to be used;
 - when getting the pid from userspace one need to consider this as
   the virtual one and use appropriate task/pid-searching functions.

[akpm@linux-foundation.org: build fix]
[akpm@linux-foundation.org: nuther build fix]
[akpm@linux-foundation.org: yet nuther build fix]
[akpm@linux-foundation.org: remove unneeded casts]
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Signed-off-by: NAlexey Dobriyan <adobriyan@openvz.org>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The namespace's proc_mnt must be kern_mount-ed to make this pointer always
valid, independently of whether the user space mounted the proc or not.  This
solves raced in proc_flush_task, etc.  with the proc_mnt switching from NULL
to not-NULL.

The initialization is done after the init's pid is created and hashed to make
proc_get_sb() finr it and get for root inode.

Sice the namespace holds the vfsmnt, vfsmnt holds the superblock and the
superblock holds the namespace we must explicitly break this circle to destroy
all the stuff.  This is done after the init of the namespace dies.  Running a
few steps forward - when init exits it will kill all its children, so no
proc_mnt will be needed after its death.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This means that proc_flush_task_mnt() is to be called for many proc mounts and
with different ids, depending on the namespace this pid is to be flushed from.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>