linux-toradex.git/kernel/fork.c, branch v2.6.23.12

sched: keep utime/stime monotonic

2007-11-16T16:12:44+00:00

sched: 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.

Combined backport for 2.6.23 of the following patches from mainline:
commit 73a2bcb0edb9ffb0b007b3546b430e2c6e415eee
Author: Peter Zijlstra 
  sched: keep utime/stime monotonic

commit 9301899be75b464ef097f0b5af7af6d9bd8f68a7
Author: Balbir Singh 
  sched: fix /proc//stat stime/utime monotonicity, part 2

Signed-off-by: Frans Pop 
CC: Peter Zijlstra 
CC: Balbir Singh 
Signed-off-by: Greg Kroah-Hartman

signalfd simplification

2007-09-20T20:19:59+00:00

This simplifies signalfd code, by avoiding it to remain attached to the
sighand during its lifetime.

In this way, the signalfd remain attached to the sighand only during
poll(2) (and select and epoll) and read(2).  This also allows to remove
all the custom "tsk == current" checks in kernel/signal.c, since
dequeue_signal() will only be called by "current".

I think this is also what Ben was suggesting time ago.

The external effect of this, is that a thread can extract only its own
private signals and the group ones.  I think this is an acceptable
behaviour, in that those are the signals the thread would be able to
fetch w/out signalfd.

Signed-off-by: Davide Libenzi 
Signed-off-by: Linus Torvalds

mm: Remove slab destructors from kmem_cache_create().

2007-07-20T01:11:58+00:00

Slab destructors were no longer supported after Christoph's
c59def9f222d44bb7e2f0a559f2906191a0862d7 change. They've been
BUGs for both slab and slub, and slob never supported them
either.

This rips out support for the dtor pointer from kmem_cache_create()
completely and fixes up every single callsite in the kernel (there were
about 224, not including the slab allocator definitions themselves,
or the documentation references).

Signed-off-by: Paul Mundt

lguest: the host code

2007-07-19T17:04:52+00:00

This is the code for the "lg.ko" module, which allows lguest guests to
be launched.

[akpm@linux-foundation.org: update for futex-new-private-futexes]
[akpm@linux-foundation.org: build fix]
[jmorris@namei.org: lguest: use hrtimers]
[akpm@linux-foundation.org: x86_64 build fix]
Signed-off-by: Rusty Russell 
Cc: Andi Kleen 
Cc: Eric Dumazet 
Cc: Thomas Gleixner 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

lguest: export symbols for lguest as a module

2007-07-19T17:04:52+00:00

lguest does some fairly lowlevel things to support a host, which
normal modules don't need:

math_state_restore:
	When the guest triggers a Device Not Available fault, we need
	to be able to restore the FPU

__put_task_struct:
	We need to hold a reference to another task for inter-guest
	I/O, and put_task_struct() is an inline function which calls
	__put_task_struct.

access_process_vm:
	We need to access another task for inter-guest I/O.

map_vm_area & __get_vm_area:
	We need to map the switcher shim (ie. monitor) at 0xFFC01000.

Signed-off-by: Rusty Russell 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

coredump masking: add an interface for core dump filter

2007-07-19T17:04:47+00:00

This patch adds an interface to set/reset flags which determines each memory
segment should be dumped or not when a core file is generated.

/proc//coredump_filter file is provided to access the flags.  You can
change the flag status for a particular process by writing to or reading from
the file.

The flag status is inherited to the child process when it is created.

Signed-off-by: Hidehiro Kawai 
Cc: Alan Cox 
Cc: David Howells 
Cc: Hugh Dickins 
Cc: Nick Piggin 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Freezer: make kernel threads nonfreezable by default

2007-07-17T17:23:02+00:00

Currently, the freezer treats all tasks as freezable, except for the kernel
threads that explicitly set the PF_NOFREEZE flag for themselves.  This
approach is problematic, since it requires every kernel thread to either
set PF_NOFREEZE explicitly, or call try_to_freeze(), even if it doesn't
care for the freezing of tasks at all.

It seems better to only require the kernel threads that want to or need to
be frozen to use some freezer-related code and to remove any
freezer-related code from the other (nonfreezable) kernel threads, which is
done in this patch.

The patch causes all kernel threads to be nonfreezable by default (ie.  to
have PF_NOFREEZE set by default) and introduces the set_freezable()
function that should be called by the freezable kernel threads in order to
unset PF_NOFREEZE.  It also makes all of the currently freezable kernel
threads call set_freezable(), so it shouldn't cause any (intentional)
change of behaviour to appear.  Additionally, it updates documentation to
describe the freezing of tasks more accurately.

[akpm@linux-foundation.org: build fixes]
Signed-off-by: Rafael J. Wysocki 
Acked-by: Nigel Cunningham 
Cc: Pavel Machek 
Cc: Oleg Nesterov 
Cc: Gautham R Shenoy 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

user namespace: add unshare

2007-07-16T16:05:47+00:00

This patch enables the unshare of user namespaces.

It adds a new clone flag CLONE_NEWUSER and implements copy_user_ns() which
resets the current user_struct and adds a new root user (uid == 0)

For now, unsharing the user namespace allows a process to reset its
user_struct accounting and uid 0 in the new user namespace should be contained
using appropriate means, for instance selinux

The plan, when the full support is complete (all uid checks covered), is to
keep the original user's rights in the original namespace, and let a process
become uid 0 in the new namespace, with full capabilities to the new
namespace.

Signed-off-by: Serge E. Hallyn 
Signed-off-by: Cedric Le Goater 
Acked-by: Pavel Emelianov 
Cc: Herbert Poetzl 
Cc: Kirill Korotaev 
Cc: Eric W. Biederman 
Cc: Chris Wright 
Cc: Stephen Smalley 
Cc: James Morris 
Cc: Andrew Morgan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

user namespace: add the framework

2007-07-16T16:05:47+00:00

Basically, it will allow a process to unshare its user_struct table,
resetting at the same time its own user_struct and all the associated
accounting.

A new root user (uid == 0) is added to the user namespace upon creation.
Such root users have full privileges and it seems that theses privileges
should be controlled through some means (process capabilities ?)

The unshare is not included in this patch.

Changes since [try #4]:
	- Updated get_user_ns and put_user_ns to accept NULL, and
	  get_user_ns to return the namespace.

Changes since [try #3]:
	- moved struct user_namespace to files user_namespace.{c,h}

Changes since [try #2]:
	- removed struct user_namespace* argument from find_user()

Changes since [try #1]:
	- removed struct user_namespace* argument from find_user()
	- added a root_user per user namespace

Signed-off-by: Cedric Le Goater 
Signed-off-by: Serge E. Hallyn 
Acked-by: Pavel Emelianov 
Cc: Herbert Poetzl 
Cc: Kirill Korotaev 
Cc: Eric W. Biederman 
Cc: Chris Wright 
Cc: Stephen Smalley 
Cc: James Morris 
Cc: Andrew Morgan 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Audit: add TTY input auditing

2007-07-16T16:05:47+00:00

Add TTY input auditing, used to audit system administrator's actions.  This is
required by various security standards such as DCID 6/3 and PCI to provide
non-repudiation of administrator's actions and to allow a review of past
actions if the administrator seems to overstep their duties or if the system
becomes misconfigured for unknown reasons.  These requirements do not make it
necessary to audit TTY output as well.

Compared to an user-space keylogger, this approach records TTY input using the
audit subsystem, correlated with other audit events, and it is completely
transparent to the user-space application (e.g.  the console ioctls still
work).

TTY input auditing works on a higher level than auditing all system calls
within the session, which would produce an overwhelming amount of mostly
useless audit events.

Add an "audit_tty" attribute, inherited across fork ().  Data read from TTYs
by process with the attribute is sent to the audit subsystem by the kernel.
The audit netlink interface is extended to allow modifying the audit_tty
attribute, and to allow sending explanatory audit events from user-space (for
example, a shell might send an event containing the final command, after the
interactive command-line editing and history expansion is performed, which
might be difficult to decipher from the TTY input alone).

Because the "audit_tty" attribute is inherited across fork (), it would be set
e.g.  for sshd restarted within an audited session.  To prevent this, the
audit_tty attribute is cleared when a process with no open TTY file
descriptors (e.g.  after daemon startup) opens a TTY.

See https://www.redhat.com/archives/linux-audit/2007-June/msg00000.html for a
more detailed rationale document for an older version of this patch.

[akpm@linux-foundation.org: build fix]
Signed-off-by: Miloslav Trmac 
Cc: Al Viro 
Cc: Alan Cox 
Cc: Paul Fulghum 
Cc: Casey Schaufler 
Cc: Steve Grubb 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds