linux-toradex.git/kernel, branch v3.3-rc7

Revert "CPU hotplug, cpusets, suspend: Don't touch cpusets during suspend/resume"

2012-03-07T16:21:19+00:00

This reverts commit 8f2f748b0656257153bcf0941df8d6060acc5ca6.

It causes some odd regression that we have not figured out, and it's too
late in the -rc series to try to figure it out now.

As reported by Konstantin Khlebnikov, it causes consistent hangs on his
laptop (Thinkpad x220: 2x cores + HT).  They can be avoided by adding
calls to "rebuild_sched_domains();" in cpuset_cpu_[in]active() for the
CPU_{ONLINE/DOWN_FAILED/DOWN_PREPARE}_FROZEN cases, but it's not at all
clear why, and it makes no sense.

Konstantin's config doesn't even have CONFIG_CPUSETS enabled, just to
make things even more interesting.  So it's not the cpusets, it's just
the scheduling domains.

So until this is understood, revert.

Bisected-reported-and-tested-by: Konstantin Khlebnikov 
Acked-by: Peter Zijlstra 
Acked-by: Ingo Molnar 
Acked-by: Srivatsa S. Bhat 
Signed-off-by: Linus Torvalds

genirq: Clear action->thread_mask if IRQ_ONESHOT is not set

2012-03-07T00:46:39+00:00

Xommit ac5637611(genirq: Unmask oneshot irqs when thread was not woken)
fails to unmask when a !IRQ_ONESHOT threaded handler is handled by
handle_level_irq.

This happens because thread_mask is or'ed unconditionally in
irq_wake_thread(), but for !IRQ_ONESHOT interrupts never cleared.  So
the check for !desc->thread_active fails and keeps the interrupt
disabled.

Keep the thread_mask zero for !IRQ_ONESHOT interrupts.

Document the thread_mask magic while at it.

Reported-and-tested-by: Sven Joachim 
Reported-and-tested-by: Stefan Lippers-Hollmann 
Cc: stable@vger.kernel.org
Signed-off-by: Thomas Gleixner 
Signed-off-by: Linus Torvalds

hung_task: fix the broken rcu_lock_break() logic

2012-03-05T23:49:42+00:00

check_hung_uninterruptible_tasks()->rcu_lock_break() introduced by
"softlockup: check all tasks in hung_task" commit ce9dbe24 looks
absolutely wrong.

	- rcu_lock_break() does put_task_struct(). If the task has exited
	  it is not safe to even read its ->state, nothing protects this
	  task_struct.

	- The TASK_DEAD checks are wrong too. Contrary to the comment, we
	  can't use it to check if the task was unhashed. It can be unhashed
	  without TASK_DEAD, or it can be valid with TASK_DEAD.

	  For example, an autoreaping task can do release_task(current)
	  long before it sets TASK_DEAD in do_exit().

	  Or, a zombie task can have ->state == TASK_DEAD but release_task()
	  was not called, and in this case we must not break the loop.

Change this code to check pid_alive() instead, and do this before we drop
the reference to the task_struct.

Note: while_each_thread() under rcu_read_lock() is not really safe, it can
livelock.  This will be fixed later, but fortunately in this case the
"max_count" logic saves us anyway.

Signed-off-by: Oleg Nesterov 
Acked-by: Frederic Weisbecker 
Acked-by: Mandeep Singh Baines 
Acked-by: Paul E. McKenney 
Cc: Tetsuo Handa 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

vfork: kill PF_STARTING

2012-03-05T23:49:42+00:00

Previously it was (ab)used by utrace.  Then it was wrongly used by the
scheduler code.

Currently it is not used, kill it before it finds the new erroneous user.

Signed-off-by: Oleg Nesterov 
Acked-by: Tejun Heo 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

coredump_wait: don't call complete_vfork_done()

2012-03-05T23:49:42+00:00

Now that CLONE_VFORK is killable, coredump_wait() no longer needs
complete_vfork_done().  zap_threads() should find and kill all tasks with
the same ->mm, this includes our parent if ->vfork_done is set.

mm_release() becomes the only caller, unexport complete_vfork_done().

Signed-off-by: Oleg Nesterov 
Acked-by: Tejun Heo 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

vfork: make it killable

2012-03-05T23:49:42+00:00

Make vfork() killable.

Change do_fork(CLONE_VFORK) to do wait_for_completion_killable().  If it
fails we do not return to the user-mode and never touch the memory shared
with our child.

However, in this case we should clear child->vfork_done before return, we
use task_lock() in do_fork()->wait_for_vfork_done() and
complete_vfork_done() to serialize with each other.

Note: now that we use task_lock() we don't really need completion, we
could turn task->vfork_done into "task_struct *wake_up_me" but this needs
some complications.

NOTE: this and the next patches do not affect in-kernel users of
CLONE_VFORK, kernel threads run with all signals ignored including
SIGKILL/SIGSTOP.

However this is obviously the user-visible change.  Not only a fatal
signal can kill the vforking parent, a sub-thread can do execve or
exit_group() and kill the thread sleeping in vfork().

Signed-off-by: Oleg Nesterov 
Acked-by: Tejun Heo 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

vfork: introduce complete_vfork_done()

2012-03-05T23:49:42+00:00

No functional changes.

Move the clear-and-complete-vfork_done code into the new trivial helper,
complete_vfork_done().

Signed-off-by: Oleg Nesterov 
Acked-by: Tejun Heo 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kprobes: return proper error code from register_kprobe()

2012-03-05T23:49:42+00:00

register_kprobe() aborts if the address of the new request falls in a
prohibited area (such as ftrace pouch, __kprobes annotated functions,
non-kernel text addresses, jump label text).  We however don't return the
right error on this abort, resulting in a silent failure - incorrect
adding/reporting of kprobes ('perf probe do_fork+18' or 'perf probe
mcount' for instance).

In V2 we are incorporating Masami Hiramatsu's  feedback.

This patch fixes it by returning -EINVAL upon failure.

While we are here, rename the label used for exit to be more appropriate.

Signed-off-by: Ananth N Mavinakayanahalli 
Signed-off-by: Prashanth K Nageshappa 
Acked-by: Masami Hiramatsu 
Cc: Jason Baron 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kmsg_dump: don't run on non-error paths by default

2012-03-05T23:49:42+00:00

Since commit 04c6862c055f ("kmsg_dump: add kmsg_dump() calls to the
reboot, halt, poweroff and emergency_restart paths"), kmsg_dump() gets
run on normal paths including poweroff and reboot.

This is less than ideal given pstore implementations that can only
represent single backtraces, since a reboot may overwrite a stored oops
before it's been picked up by userspace.  In addition, some pstore
backends may have low performance and provide a significant delay in
reboot as a result.

This patch adds a printk.always_kmsg_dump kernel parameter (which can also
be changed from userspace).  Without it, the code will only be run on
failure paths rather than on normal paths.  The option can be enabled in
environments where there's a desire to attempt to audit whether or not a
reboot was cleanly requested or not.

Signed-off-by: Matthew Garrett 
Acked-by: Seiji Aguchi 
Cc: Seiji Aguchi 
Cc: David Woodhouse 
Cc: Marco Stornelli 
Cc: Artem Bityutskiy 
Cc: KOSAKI Motohiro 
Cc: Vivek Goyal 
Cc: Don Zickus 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branches 'core-urgent-for-linus', 'perf-urgent-for-linus' and 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2012-03-02T19:38:43+00:00

Pulling latest branches from Ingo:

* 'core-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  memblock: Fix size aligning of memblock_alloc_base_nid()

* 'perf-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  perf probe: Ensure offset provided is not greater than function length without DWARF info too
  perf tools: Ensure comm string is properly terminated
  perf probe: Ensure offset provided is not greater than function length
  perf evlist: Return first evsel for non-sample event on old kernel
  perf/hwbp: Fix a possible memory leak

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  CPU hotplug, cpusets, suspend: Don't touch cpusets during suspend/resume