Incrementally update my proc-dont-lock-task_structs-indefinitely patches so
that they work with struct pid instead of struct task_ref.

Mostly this is a straight 1-1 substitution.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Every inode in /proc holds a reference to a struct task_struct.  If a
directory or file is opened and remains open after the the task exits this
pinning continues.  With 8K stacks on a 32bit machine the amount pinned per
file descriptor is about 10K.

Normally I would figure a reasonable per user process limit is about 100
processes.  With 80 processes, with a 1000 file descriptors each I can trigger
the 00M killer on a 32bit kernel, because I have pinned about 800MB of useless
data.

This patch replaces the struct task_struct pointer with a pointer to a struct
task_ref which has a struct task_struct pointer.  The so the pinning of dead
tasks does not happen.

The code now has to contend with the fact that the task may now exit at any
time.  Which is a little but not muh more complicated.

With this change it takes about 1000 processes each opening up 1000 file
descriptors before I can trigger the OOM killer.  Much better.

[mlp@google.com: task_mmu small fixes]
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Paul Jackson <pj@sgi.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Albert Cahalan <acahalan@gmail.com>
Signed-off-by: NPrasanna Meda <mlp@google.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Currently in /proc at several different places we define buffers to hold a
process id, or a file descriptor .  In most of them we use either a hard coded
number or a different define.  Modify them all to use PROC_NUMBUF, so the code
has a chance of being maintained.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Like the bug Oleg spotted in first_tid there was also a small off by one
error in first_tgid, when a seek was done on the /proc directory.  This
fixes that and changes the code structure to make it a little more obvious
what is going on.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Since we no longer need the tasklist_lock for get_task_struct the lookup
methods no longer need the tasklist_lock.

This just depends on my previous patch that makes get_task_struct() rcu
safe.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

We don't need the tasklist_lock to safely iterate through processes
anymore.

This depends on my previous to task patches that make get_task_struct rcu
safe, and that make next_task() rcu safe.  I haven't gotten
first_tid/next_tid yet only because next_thread is missing an
rcu_dereference.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

There are a couple of problems this patch addresses.
- /proc/<tgid>/task currently does not work correctly if you stop reading
  in the middle of a directory.

- /proc/ currently requires a full pass through the task list with
  the tasklist lock held, to determine there are no more processes to read.

- The hand rolled integer to string conversion does not properly running
  out of buffer space.

- We seem to be batching reading of pids from the tasklist without reason,
  and complicating the logic of the code.

This patch addresses that by changing how tasks are processed.  A
first_<task_type> function is built that handles restarts, and a
next_<task_type> function is built that just advances to the next task.

first_<task_type> when it detects a restart usually uses find_task_by_pid.  If
that doesn't work because there has been a seek on the directory, or we have
already given a complete directory listing, it first checks the number tasks
of that type, and only if we are under that count does it walk through all of
the tasks to find the one we are interested in.

The code that fills in the directory is simpler because there is only a single
for loop.

The hand rolled integer to string conversion is replaced by snprintf which
should handle the the out of buffer case correctly.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

proc_lookup and task exiting are not synchronized, although some of the
previous code may have suggested that.  Every time before we reuse a dentry
namei.c calls d_op->derevalidate which prevents us from reusing a stale dcache
entry.  Unfortunately it does not prevent us from returning a stale dcache
entry.  This race has been explicitly plugged in proc_pid_lookup but there is
nothing to confine it to just that proc lookup function.

So to prevent the race I call revalidate explictily in all of the proc lookup
functions after I call d_add, and report an error if the revalidate does not
succeed.

Years ago Al Viro did something similar but those changes got lost in the
churn.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

To keep the dcache from filling up with dead /proc entries we flush them on
process exit.  However over the years that code has gotten hairy with a
dentry_pointer and a lock in task_struct and misdocumented as a correctness
feature.

I have rewritten this code to look and see if we have a corresponding entry in
the dcache and if so flush it on process exit.  This removes the extra fields
in the task_struct and allows me to trivially handle the case of a
/proc/<tgid>/task/<pid> entry as well as the current /proc/<pid> entries.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

All of the functions for proc_maps_operations are already defined in
task_mmu.c so move the operations structure to keep the functionality
together.

Since task_nommu.c implements a dummy version of /proc/<pid>/maps give it a
simplified version of proc_maps_operations that it can modify to best suit its
needs.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Use getattr to get an accurate link count when needed.  This is cheaper and
more accurate than trying to derive it by walking the thread list of a
process.

Especially as it happens when needed stat instead of at readdir time.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Long ago and far away in 2.2 we started checking to ensure the files we
displayed in /proc were visible to the current process.  It was an
unsophisticated time and no one was worried about functions full of FIXMES in
a stable kernel.  As time passed the function became sacred and was enshrined
in the shrine of how things have always been.  The fixes came in but only to
keep the function working no one really remembering or documenting why we did
things that way.

The intent and the functionality make a lot of sense.  Don't let /proc be an
access point for files a process can see no other way.  The implementation
however is completely wrong.

We are currently checking the root directories of the two processes, we are
not checking the actual file descriptors themselves.

We are strangely checking with a permission method instead of just when we use
the data.

This patch fixes the logic to actually check the file descriptors and make a
note that implementing a permission method for this part of /proc almost
certainly indicates a bug in the reasoning.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The inode operations only exist to support the proc_permission function.
Currently mem_read and mem_write have all the same permission checks as
ptrace.  The fs check makes no sense in this context, and we can trivially get
around it by calling ptrace.

So simply the code by killing the strange weird case.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

First we can access every /proc/<tgid>/task/<pid> directory as /proc/<pid> so
proc_task_permission is not usefully limiting visibility.

Second having related filesystems information should have nothing to do with
process visibility.  kill does not implement any checks like that.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The sole renaming use of proc_inode.type is to discover the file descriptor
number, so just store the file descriptor number and don't wory about
processing this field.  This removes any /proc limits on the maximum number of
file descriptors, and clears the path to make the hard coded /proc inode
numbers go away.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Currently in /proc if the task is dumpable all of files are owned by the tasks
effective users.  Otherwise the files are owned by root.  Unless it is the
/proc/<tgid>/ or /proc/<tgid>/task/<pid> directory in that case we always make
the directory owned by the effective user.

However the special case for directories is pointless except as a way to read
the effective user, because the permissions on both of those directories are
world readable, and executable.

/proc/<tgid>/status provides a much better way to read a processes effecitve
userid, so it is silly to try to provide that on the directory.

So this patch simplifies the code by removing a pointless special case and
gets us one step closer to being able to remove the hard coded /proc inode
numbers.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The removed fields are already set by proc_alloc_inode.  Initializing them in
proc_alloc_inode implies they need it for proper cleanup.  At least ei->pde
was not set on all paths making it look like proc_alloc_inode was buggy.  So
just remove the redundant assignments.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

We already call everything except do_proc_readlink outside of the BKL in
proc_pid_followlink, and there appears to be nothing in do_proc_readlink that
needs any special protection.

So remove this leftover from one of the BKL cleanup efforts.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I noticed recently that my CONFIG_CRYPTO_MD5 turned into a y again instead
of m.  It turns out that CONFIG_NFSD_V4 is selecting it to be y even though
I've chosen to compile nfsd as a module.

In general when we have a bool sitting under a tristate it is better to
select things you need from the tristate rather than the bool since that
allows the things you select to be modules.

The following patch does it for nfsd.
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>
Cc: Neil Brown <neilb@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add the IOCTLs of the Gigaset drivers to compat_ioctl.h in order to make
them available for 32 bit programs on 64 bit platforms.  Please merge.
Signed-off-by: NHansjoerg Lipp <hjlipp@web.de>
Acked-by: NTilman Schmidt <tilman@imap.cc>
Cc: Karsten Keil <kkeil@suse.de>
Cc: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch adds "-o bh" option to force use of buffer_heads.  This option
is needed when we make "nobh" as default - and if we run into problems.
Signed-off-by: NBadari Pulavarty <pbadari@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Cc: <reiserfs-dev@namesys.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add a /proc/<pid>/attr/keycreate entry that stores the appropriate context for
newly-created keys.  Modify the selinux_key_alloc hook to make use of the new
entry.  Update the flask headers to include a new "setkeycreate" permission
for processes.  Update the flask headers to include a new "create" permission
for keys.  Use the create permission to restrict which SIDs each task can
assign to newly-created keys.  Add a new parameter to the security hook
"security_key_alloc" to indicate whether it is being invoked by the kernel, or
from userspace.  If it is being invoked by the kernel, the security hook
should never fail.  Update the documentation to reflect these changes.
Signed-off-by: NMichael LeMay <mdlemay@epoch.ncsc.mil>
Signed-off-by: NJames Morris <jmorris@namei.org>
Signed-off-by: NDavid Howells <dhowells@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch converts the combination of list_del(A) and list_add(A, B) to
list_move(A, B) under fs/.

Cc: Ian Kent <raven@themaw.net>
Acked-by: NJoel Becker <joel.becker@oracle.com>
Cc: Neil Brown <neilb@cse.unsw.edu.au>
Cc: Hans Reiser <reiserfs-dev@namesys.com>
Cc: Urban Widmark <urban@teststation.com>
Acked-by: NDavid Howells <dhowells@redhat.com>
Acked-by: NMark Fasheh <mark.fasheh@oracle.com>
Signed-off-by: NAkinobu Mita <mita@miraclelinux.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch converts the combination of list_del(A) and list_add(A, B) to
list_move(A, B).

Cc: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Ram Pai <linuxram@us.ibm.com>
Signed-off-by: NAkinobu Mita <mita@miraclelinux.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch converts list_add(A, B.prev) to list_add_tail(A, &B) for
readability.
Acked-by: NKarsten Keil <kkeil@suse.de>
Cc: Jan Harkes <jaharkes@cs.cmu.edu>
Acked-by: NJan Kara <jack@suse.cz>
AOLed-by: NDavid Woodhouse <dwmw2@infradead.org>
Cc: Sridhar Samudrala <sri@us.ibm.com>
Signed-off-by: NAkinobu Mita <mita@miraclelinux.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

binfmt_flat.c calls set_personality with PER_LINUX as the personality.
On the arm architecture this results in the program running in 26bit
usermode.  PER_LINUX_32BIT should be used instead.  This doesn't affect
other architectures that use binfmt_flat.
Signed-off-by: NGreg Ungerer <gerg@uclinux.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Cc: Nathan Scott <nathans@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Trond had apparently merged the same patch twice, causing a duplicate
include of the "internal.h" file, with resulting obvious confusion.

Tssk.  I'm the only one allowed to send out trees that don't even
compile! Who does this Trond guy think he is?
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

likely profiling shows that the following is a miss.

After boot:
[+- ] Type | # True | # False | Function:Filename@Line
+unlikely |     1074|        0  prune_dcache()@:fs/dcache.c@409

After a bonnie++ run:
+unlikely |    66716|    19584  prune_dcache()@:fs/dcache.c@409

So remove it.
Signed-off-by: NHua Zhong <hzhong@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Things which force me think a little: why so?
Signed-off-by: NEvgeniy Dushistov <dushistov@mail.ru>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

When the linkat() syscall was added the flag parameter was added in the
last minute but it wasn't used so far.  The following patch should change
that.  My tests show that this is all that's needed.

If OLDNAME is a symlink setting the flag causes linkat to follow the
symlink and create a hardlink with the target.  This is actually the
behavior POSIX demands for link() as well but Linux wisely does not do
this.  With this flag (which will most likely be in the next POSIX
revision) the programmer can choose the behavior, defaulting to the safe
variant.  As a side effect it is now possible to implement a
POSIX-compliant link(2) function for those who are interested.

  touch file
  ln -s file symlink

  linkat(fd, "symlink", fd, "newlink", 0)
    -> newlink is hardlink of symlink

  linkat(fd, "symlink", fd, "newlink", AT_SYMLINK_FOLLOW)
    -> newlink is hardlink of file

The value of AT_SYMLINK_FOLLOW is determined by the definition we already
use in glibc.
Signed-off-by: NUlrich Drepper <drepper@redhat.com>
Acked-by: NAl Viro <viro@zeniv.linux.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

If you do a poll() call with timeout -1, the wait will be a big number
(depending on HZ) instead of infinite wait, since -1 is passed to the
msecs_to_jiffies function.
Signed-off-by: NFrode Isaksen <frode.isaksen@gmail.com>
Acked-by: NNishanth Aravamudan <nacc@us.ibm.com>
Cc: David Woodhouse <dwmw2@infradead.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

%s is only valid if array is known to contain NUL or precision is given and
does not exceed the size of array.
Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>
Cc: Roman Zippel <zippel@linux-m68k.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Update smbiod to use kthread instead of deprecated kernel_thread.

[akpm@osdl.org: cleanup]
Signed-off-by: NSerge E. Hallyn <serue@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

coverity found two needless checks in vfs_inode.c (cid #1165 and #1164)
In both cases inode is always NULL when we goto error; either because it
is still initialized to NULL or is set to NULL explicitly. This patch
simply removes these checks to save some code.
Signed-off-by: NEric Sesterhenn <snakebyte@gmx.de>
Acked-by: NEric Van Hensbergen <ericvh@gmail.com>
Cc: Ron Minnich <rminnich@lanl.gov>
Cc: Latchesar Ionkov <lucho@ionkov.net>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

VFS uses current->files pointer as lock owner ID, and it wouldn't be
prudent to expose this value to userspace.  So scramble it with XTEA using
a per connection random key, known only to the kernel.  Only one direction
needs to be implemented, since the ID is never sent in the reverse
direction.

The XTEA algorithm is implemented inline since it's simple enough to do so,
and this adds less complexity than if the crypto API were used.

Thanks to Jesper Juhl for the idea.
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add synchronous request interruption.  This is needed for file locking
operations which have to be interruptible.  However filesystem may implement
interruptibility of other operations (e.g.  like NFS 'intr' mount option).
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Rename the 'interrupted' flag to 'aborted', since it indicates exactly that,
and next patch will introduce an 'interrupted' flag for a
Signed-off-by: NMiklos Szeredi <miklos@szeredi.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>