linux-toradex.git/kernel, branch v3.4.16

Revert "cgroup: Drop task_lock(parent) on cgroup_fork()"

2012-10-28T17:14:14+00:00

commit 9bb71308b8133d643648776243e4d5599b1c193d upstream.

This reverts commit 7e381b0eb1e1a9805c37335562e8dc02e7d7848c.

The commit incorrectly assumed that fork path always performed
threadgroup_change_begin/end() and depended on that for
synchronization against task exit and cgroup migration paths instead
of explicitly grabbing task_lock().

threadgroup_change is not locked when forking a new process (as
opposed to a new thread in the same process) and even if it were it
wouldn't be effective as different processes use different threadgroup
locks.

Revert the incorrect optimization.

Signed-off-by: Tejun Heo 
LKML-Reference: <20121008020000.GB2575@localhost>
Acked-by: Li Zefan 
Bitterly-Acked-by: Frederic Weisbecker 
Signed-off-by: Greg Kroah-Hartman

Revert "cgroup: Remove task_lock() from cgroup_post_fork()"

2012-10-28T17:14:14+00:00

commit d87838321124061f6c935069d97f37010fa417e6 upstream.

This reverts commit 7e3aa30ac8c904a706518b725c451bb486daaae9.

The commit incorrectly assumed that fork path always performed
threadgroup_change_begin/end() and depended on that for
synchronization against task exit and cgroup migration paths instead
of explicitly grabbing task_lock().

threadgroup_change is not locked when forking a new process (as
opposed to a new thread in the same process) and even if it were it
wouldn't be effective as different processes use different threadgroup
locks.

Revert the incorrect optimization.

Signed-off-by: Tejun Heo 
LKML-Reference: <20121008020000.GB2575@localhost>
Acked-by: Li Zefan 
Cc: Frederic Weisbecker 
Signed-off-by: Greg Kroah-Hartman

cgroup: notify_on_release may not be triggered in some cases

2012-10-28T17:14:14+00:00

commit 1f5320d5972aa50d3e8d2b227b636b370e608359 upstream.

notify_on_release must be triggered when the last process in a cgroup is
move to another. But if the first(and only) process in a cgroup is moved to
another, notify_on_release is not triggered.

	# mkdir /cgroup/cpu/SRC
	# mkdir /cgroup/cpu/DST
	#
	# echo 1 >/cgroup/cpu/SRC/notify_on_release
	# echo 1 >/cgroup/cpu/DST/notify_on_release
	#
	# sleep 300 &
	[1] 8629
	#
	# echo 8629 >/cgroup/cpu/SRC/tasks
	# echo 8629 >/cgroup/cpu/DST/tasks
	-> notify_on_release for /SRC must be triggered at this point,
	   but it isn't.

This is because put_css_set() is called before setting CGRP_RELEASABLE
in cgroup_task_migrate(), and is a regression introduce by the
commit:74a1166d(cgroups: make procs file writable), which was merged
into v3.0.

Acked-by: Li Zefan 
Cc: Ben Blum 
Signed-off-by: Daisuke Nishimura 
Signed-off-by: Tejun Heo 
Signed-off-by: Greg Kroah-Hartman

use clamp_t in UNAME26 fix

2012-10-28T17:14:13+00:00

commit 31fd84b95eb211d5db460a1dda85e004800a7b52 upstream.

The min/max call needed to have explicit types on some architectures
(e.g. mn10300). Use clamp_t instead to avoid the warning:

  kernel/sys.c: In function 'override_release':
  kernel/sys.c:1287:10: warning: comparison of distinct pointer types lacks a cast [enabled by default]

Reported-by: Fengguang Wu 
Signed-off-by: Kees Cook 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

kernel/sys.c: fix stack memory content leak via UNAME26

2012-10-28T17:14:13+00:00

commit 2702b1526c7278c4d65d78de209a465d4de2885e upstream.

Calling uname() with the UNAME26 personality set allows a leak of kernel
stack contents.  This fixes it by defensively calculating the length of
copy_to_user() call, making the len argument unsigned, and initializing
the stack buffer to zero (now technically unneeded, but hey, overkill).

CVE-2012-0957

Reported-by: PaX Team 
Signed-off-by: Kees Cook 
Cc: Andi Kleen 
Cc: PaX Team 
Cc: Brad Spengler 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

kdb,vt_console: Fix missed data due to pager overruns

2012-10-21T16:27:59+00:00

commit 17b572e82032bc246324ce136696656b66d4e3f1 upstream.

It is possible to miss data when using the kdb pager.  The kdb pager
does not pay attention to the maximum column constraint of the screen
or serial terminal.  This result is not incrementing the shown lines
correctly and the pager will print more lines that fit on the screen.
Obviously that is less than useful when using a VGA console where you
cannot scroll back.

The pager will now look at the kdb_buffer string to see how many
characters are printed.  It might not be perfect considering you can
output ASCII that might move the cursor position, but it is a
substantially better approximation for viewing dmesg and trace logs.

This also means that the vt screen needs to set the kdb COLUMNS
variable.

Signed-off-by: Jason Wessel 
Signed-off-by: Greg Kroah-Hartman

timers: Fix endless looping between cascade() and internal_add_timer()

2012-10-21T16:27:59+00:00

commit 26cff4e2aa4d666dc6a120ea34336b5057e3e187 upstream.

Adding two (or more) timers with large values for "expires" (they have
to reside within tv5 in the same list) leads to endless looping
between cascade() and internal_add_timer() in case CONFIG_BASE_SMALL
is one and jiffies are crossing the value 1 << 18. The bug was
introduced between 2.6.11 and 2.6.12 (and survived for quite some
time).

This patch ensures that when cascade() is called timers within tv5 are
not added endlessly to their own list again, instead they are added to
the next lower tv level tv4 (as expected).

Signed-off-by: Christian Hildner 
Reviewed-by: Jan Kiszka 
Link: http://lkml.kernel.org/r/98673C87CB31274881CFFE0B65ECC87B0F5FC1963E@DEFTHW99EA4MSX.ww902.siemens.net
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

module: taint kernel when lve module is loaded

2012-10-21T16:27:59+00:00

commit c99af3752bb52ba3aece5315279a57a477edfaf1 upstream.

Cloudlinux have a product called lve that includes a kernel module. This
was previously GPLed but is now under a proprietary license, but the
module continues to declare MODULE_LICENSE("GPL") and makes use of some
EXPORT_SYMBOL_GPL symbols. Forcibly taint it in order to avoid this.

Signed-off-by: Matthew Garrett 
Cc: Alex Lyashkov 
Signed-off-by: Rusty Russell 
Signed-off-by: Greg Kroah-Hartman

sched: Fix migration thread runtime bogosity

2012-10-12T20:39:01+00:00

commit 8f6189684eb4e85e6c593cd710693f09c944450a upstream.

Make stop scheduler class do the same accounting as other classes,

Migration threads can be caught in the act while doing exec balancing,
leading to the below due to use of unmaintained ->se.exec_start.  The
load that triggered this particular instance was an apparently out of
control heavily threaded application that does system monitoring in
what equated to an exec bomb, with one of the VERY frequently migrated
tasks being ps.

%CPU   PID USER     CMD
99.3    45 root     [migration/10]
97.7    53 root     [migration/12]
97.0    57 root     [migration/13]
90.1    49 root     [migration/11]
89.6    65 root     [migration/15]
88.7    17 root     [migration/3]
80.4    37 root     [migration/8]
78.1    41 root     [migration/9]
44.2    13 root     [migration/2]

Signed-off-by: Mike Galbraith 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1344051854.6739.19.camel@marge.simpson.net
Signed-off-by: Thomas Gleixner 
Cc: Steven Rostedt 
Signed-off-by: Greg Kroah-Hartman

CPU hotplug, cpusets, suspend: Don't modify cpusets during suspend/resume

2012-10-12T20:38:57+00:00

commit d35be8bab9b0ce44bed4b9453f86ebf64062721e upstream.

In the event of CPU hotplug, the kernel modifies the cpusets' cpus_allowed
masks as and when necessary to ensure that the tasks belonging to the cpusets
have some place (online CPUs) to run on. And regular CPU hotplug is
destructive in the sense that the kernel doesn't remember the original cpuset
configurations set by the user, across hotplug operations.

However, suspend/resume (which uses CPU hotplug) is a special case in which
the kernel has the responsibility to restore the system (during resume), to
exactly the same state it was in before suspend.

In order to achieve that, do the following:

1. Don't modify cpusets during suspend/resume. At all.
   In particular, don't move the tasks from one cpuset to another, and
   don't modify any cpuset's cpus_allowed mask. So, simply ignore cpusets
   during the CPU hotplug operations that are carried out in the
   suspend/resume path.

2. However, cpusets and sched domains are related. We just want to avoid
   altering cpusets alone. So, to keep the sched domains updated, build
   a single sched domain (containing all active cpus) during each of the
   CPU hotplug operations carried out in s/r path, effectively ignoring
   the cpusets' cpus_allowed masks.

   (Since userspace is frozen while doing all this, it will go unnoticed.)

3. During the last CPU online operation during resume, build the sched
   domains by looking up the (unaltered) cpusets' cpus_allowed masks.
   That will bring back the system to the same original state as it was in
   before suspend.

Ultimately, this will not only solve the cpuset problem related to suspend
resume (ie., restores the cpusets to exactly what it was before suspend, by
not touching it at all) but also speeds up suspend/resume because we avoid
running cpuset update code for every CPU being offlined/onlined.

Signed-off-by: Srivatsa S. Bhat 
Signed-off-by: Peter Zijlstra 
Cc: Linus Torvalds 
Cc: Andrew Morton 
Cc: Thomas Gleixner 
Link: http://lkml.kernel.org/r/20120524141611.3692.20155.stgit@srivatsabhat.in.ibm.com
Signed-off-by: Ingo Molnar 
Signed-off-by: Preeti U Murthy 
Signed-off-by: Greg Kroah-Hartman