linux-stable.git/kernel, branch v3.4.8

futex: Forbid uaddr == uaddr2 in futex_wait_requeue_pi()

2012-08-09T15:31:53+00:00

commit 6f7b0a2a5c0fb03be7c25bd1745baa50582348ef upstream.

If uaddr == uaddr2, then we have broken the rule of only requeueing
from a non-pi futex to a pi futex with this call. If we attempt this,
as the trinity test suite manages to do, we miss early wakeups as
q.key is equal to key2 (because they are the same uaddr). We will then
attempt to dereference the pi_mutex (which would exist had the futex_q
been properly requeued to a pi futex) and trigger a NULL pointer
dereference.

Signed-off-by: Darren Hart 
Cc: Dave Jones 
Link: http://lkml.kernel.org/r/ad82bfe7f7d130247fbe2b5b4275654807774227.1342809673.git.dvhart@linux.intel.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

futex: Fix bug in WARN_ON for NULL q.pi_state

2012-08-09T15:31:53+00:00

commit f27071cb7fe3e1d37a9dbe6c0dfc5395cd40fa43 upstream.

The WARN_ON in futex_wait_requeue_pi() for a NULL q.pi_state was testing
the address (&q.pi_state) of the pointer instead of the value
(q.pi_state) of the pointer. Correct it accordingly.

Signed-off-by: Darren Hart 
Cc: Dave Jones 
Link: http://lkml.kernel.org/r/1c85d97f6e5f79ec389a4ead3e367363c74bd09a.1342809673.git.dvhart@linux.intel.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

futex: Test for pi_mutex on fault in futex_wait_requeue_pi()

2012-08-09T15:31:53+00:00

commit b6070a8d9853eda010a549fa9a09eb8d7269b929 upstream.

If fixup_pi_state_owner() faults, pi_mutex may be NULL. Test
for pi_mutex != NULL before testing the owner against current
and possibly unlocking it.

Signed-off-by: Darren Hart 
Cc: Dave Jones 
Cc: Dan Carpenter 
Link: http://lkml.kernel.org/r/dc59890338fc413606f04e5c5b131530734dae3d.1342809673.git.dvhart@linux.intel.com
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

posix_types.h: Cleanup stale __NFDBITS and related definitions

2012-08-09T15:31:39+00:00

commit 8ded2bbc1845e19c771eb55209aab166ef011243 upstream.

Recently, glibc made a change to suppress sign-conversion warnings in
FD_SET (glibc commit ceb9e56b3d1).  This uncovered an issue with the
kernel's definition of __NFDBITS if applications #include
 after including .  A build failure would
be seen when passing the -Werror=sign-compare and -D_FORTIFY_SOURCE=2
flags to gcc.

It was suggested that the kernel should either match the glibc
definition of __NFDBITS or remove that entirely.  The current in-kernel
uses of __NFDBITS can be replaced with BITS_PER_LONG, and there are no
uses of the related __FDELT and __FDMASK defines.  Given that, we'll
continue the cleanup that was started with commit 8b3d1cda4f5f
("posix_types: Remove fd_set macros") and drop the remaining unused
macros.

Additionally, linux/time.h has similar macros defined that expand to
nothing so we'll remove those at the same time.

Reported-by: Jeff Law 
Suggested-by: Linus Torvalds 
Signed-off-by: Josh Boyer 
[ .. and fix up whitespace as per akpm ]
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

workqueue: perform cpu down operations from low priority cpu_notifier()

2012-08-09T15:31:37+00:00

commit 6575820221f7a4dd6eadecf7bf83cdd154335eda upstream.

Currently, all workqueue cpu hotplug operations run off
CPU_PRI_WORKQUEUE which is higher than normal notifiers.  This is to
ensure that workqueue is up and running while bringing up a CPU before
other notifiers try to use workqueue on the CPU.

Per-cpu workqueues are supposed to remain working and bound to the CPU
for normal CPU_DOWN_PREPARE notifiers.  This holds mostly true even
with workqueue offlining running with higher priority because
workqueue CPU_DOWN_PREPARE only creates a bound trustee thread which
runs the per-cpu workqueue without concurrency management without
explicitly detaching the existing workers.

However, if the trustee needs to create new workers, it creates
unbound workers which may wander off to other CPUs while
CPU_DOWN_PREPARE notifiers are in progress.  Furthermore, if the CPU
down is cancelled, the per-CPU workqueue may end up with workers which
aren't bound to the CPU.

While reliably reproducible with a convoluted artificial test-case
involving scheduling and flushing CPU burning work items from CPU down
notifiers, this isn't very likely to happen in the wild, and, even
when it happens, the effects are likely to be hidden by the following
successful CPU down.

Fix it by using different priorities for up and down notifiers - high
priority for up operations and low priority for down operations.

Workqueue cpu hotplug operations will soon go through further cleanup.

Signed-off-by: Tejun Heo 
Acked-by: "Rafael J. Wysocki" 
Signed-off-by: Greg Kroah-Hartman

ftrace: Disable function tracing during suspend/resume and hibernation, again

2012-08-09T15:31:29+00:00

commit 443772d408a25af62498793f6f805ce3c559309a upstream.

If function tracing is enabled for some of the low-level suspend/resume
functions, it leads to triple fault during resume from suspend, ultimately
ending up in a reboot instead of a resume (or a total refusal to come out
of suspended state, on some machines).

This issue was explained in more detail in commit f42ac38c59e0a03d (ftrace:
disable tracing for suspend to ram). However, the changes made by that commit
got reverted by commit cbe2f5a6e84eebb (tracing: allow tracing of
suspend/resume & hibernation code again). So, unfortunately since things are
not yet robust enough to allow tracing of low-level suspend/resume functions,
suspend/resume is still broken when ftrace is enabled.

So fix this by disabling function tracing during suspend/resume & hibernation.

Signed-off-by: Srivatsa S. Bhat 
Signed-off-by: Rafael J. Wysocki 
Signed-off-by: Greg Kroah-Hartman

ntp: Fix STA_INS/DEL clearing bug

2012-07-29T15:04:18+00:00

commit 6b1859dba01c7d512b72d77e3fd7da8354235189 upstream.

In commit 6b43ae8a619d17c4935c3320d2ef9e92bdeed05d, I
introduced a bug that kept the STA_INS or STA_DEL bit
from being cleared from time_status via adjtimex()
without forcing STA_PLL first.

Usually once the STA_INS is set, it isn't cleared
until the leap second is applied, so its unlikely this
affected anyone. However during testing I noticed it
took some effort to cancel a leap second once STA_INS
was set.

Signed-off-by: John Stultz 
Cc: Ingo Molnar 
Cc: Peter Zijlstra 
Cc: Richard Cochran 
Cc: Prarit Bhargava 
Link: http://lkml.kernel.org/r/1342156917-25092-2-git-send-email-john.stultz@linaro.org
Signed-off-by: Thomas Gleixner 
Signed-off-by: Greg Kroah-Hartman

timekeeping: Add missing update call in timekeeping_resume()

2012-07-19T15:59:00+00:00

This is a backport of 3e997130bd2e8c6f5aaa49d6e3161d4d29b43ab0

The leap second rework unearthed another issue of inconsistent data.

On timekeeping_resume() the timekeeper data is updated, but nothing
calls timekeeping_update(), so now the update code in the timer
interrupt sees stale values.

This has been the case before those changes, but then the timer
interrupt was using stale data as well so this went unnoticed for quite
some time.

Add the missing update call, so all the data is consistent everywhere.

Reported-by: Andreas Schwab 
Reported-and-tested-by: "Rafael J. Wysocki" 
Reported-and-tested-by: Martin Steigerwald 
Cc: John Stultz 
Cc: Ingo Molnar 
Cc: Peter Zijlstra ,
Cc: Prarit Bhargava 
Signed-off-by: Thomas Gleixner 
Signed-off-by: John Stultz 
Signed-off-by: Linus Torvalds 
Cc: Prarit Bhargava 
Cc: Thomas Gleixner 
Signed-off-by: John Stultz 
Signed-off-by: Greg Kroah-Hartman

hrtimer: Update hrtimer base offsets each hrtimer_interrupt

2012-07-19T15:59:00+00:00

This is a backport of 5baefd6d84163443215f4a99f6a20f054ef11236

The update of the hrtimer base offsets on all cpus cannot be made
atomically from the timekeeper.lock held and interrupt disabled region
as smp function calls are not allowed there.

clock_was_set(), which enforces the update on all cpus, is called
either from preemptible process context in case of do_settimeofday()
or from the softirq context when the offset modification happened in
the timer interrupt itself due to a leap second.

In both cases there is a race window for an hrtimer interrupt between
dropping timekeeper lock, enabling interrupts and clock_was_set()
issuing the updates. Any interrupt which arrives in that window will
see the new time but operate on stale offsets.

So we need to make sure that an hrtimer interrupt always sees a
consistent state of time and offsets.

ktime_get_update_offsets() allows us to get the current monotonic time
and update the per cpu hrtimer base offsets from hrtimer_interrupt()
to capture a consistent state of monotonic time and the offsets. The
function replaces the existing ktime_get() calls in hrtimer_interrupt().

The overhead of the new function vs. ktime_get() is minimal as it just
adds two store operations.

This ensures that any changes to realtime or boottime offsets are
noticed and stored into the per-cpu hrtimer base structures, prior to
any hrtimer expiration and guarantees that timers are not expired early.

Signed-off-by: John Stultz 
Reviewed-by: Ingo Molnar 
Acked-by: Peter Zijlstra 
Acked-by: Prarit Bhargava 
Link: http://lkml.kernel.org/r/1341960205-56738-8-git-send-email-johnstul@us.ibm.com
Signed-off-by: Thomas Gleixner 
Cc: Prarit Bhargava 
Cc: Thomas Gleixner 
Signed-off-by: John Stultz 
Signed-off-by: Greg Kroah-Hartman

timekeeping: Provide hrtimer update function

2012-07-19T15:59:00+00:00

This is a backport of f6c06abfb3972ad4914cef57d8348fcb2932bc3b

To finally fix the infamous leap second issue and other race windows
caused by functions which change the offsets between the various time
bases (CLOCK_MONOTONIC, CLOCK_REALTIME and CLOCK_BOOTTIME) we need a
function which atomically gets the current monotonic time and updates
the offsets of CLOCK_REALTIME and CLOCK_BOOTTIME with minimalistic
overhead. The previous patch which provides ktime_t offsets allows us
to make this function almost as cheap as ktime_get() which is going to
be replaced in hrtimer_interrupt().

Signed-off-by: Thomas Gleixner 
Reviewed-by: Ingo Molnar 
Acked-by: Peter Zijlstra 
Acked-by: Prarit Bhargava 
Signed-off-by: John Stultz 
Link: http://lkml.kernel.org/r/1341960205-56738-7-git-send-email-johnstul@us.ibm.com
Signed-off-by: Thomas Gleixner 
Cc: Prarit Bhargava 
Cc: Thomas Gleixner 
Signed-off-by: John Stultz 
Signed-off-by: Greg Kroah-Hartman