update_vsyscall() did not provide the wall_to_monotoinc offset,
so arch specific implementations tend to reference wall_to_monotonic
directly. This limits future cleanups in the timekeeping core, so
this patch fixes the update_vsyscall interface to provide
wall_to_monotonic, allowing wall_to_monotonic to be made static
as planned in Documentation/feature-removal-schedule.txt
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Anton Blanchard <anton@samba.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Tony Luck <tony.luck@intel.com>
LKML-Reference: <1279068988-21864-7-git-send-email-johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

Now that all arches have been converted over to use generic time via
clocksources or arch_gettimeoffset(), we can remove the GENERIC_TIME
config option and simplify the generic code.
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <1279068988-21864-4-git-send-email-johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

After accidentally misusing timespec_add_safe, I wanted to make sure
we don't accidently trip over that issue again, so I created a simple
timespec_add() function which we can use to replace the instances
of timespec_add_safe() that don't want the overflow detection.
Signed-off-by: NJohn Stultz <johnstul@us.ibm.com>
LKML-Reference: <1279068988-21864-3-git-send-email-johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

The kdb code should not toggle the sysrq state in case an end user
wants to try and resume the normal kernel execution.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Acked-by: NDmitry Torokhov <dmitry.torokhov@gmail.com>

Immediately following an exit from the kdb shell the kgdb_connected
variable should be set to zero, unless there are breakpoints planted.
If the kgdb_connected variable is not zeroed out with kdb, it is
impossible to turn off kdb.

This patch is merely a work around for now, the real fix will check
for the breakpoints.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

In the process of merging kdb to the mainline, the kdb lsmod command
stopped printing the base load address of kernel modules.  This is
needed for using kdb in conjunction with external tools such as gdb.

Simply restore the functionality by adding a kdb_printf for the base
load address of the kernel modules.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

The gdbserial protocol handler should return an empty packet instead
of an error string when ever it responds to a command it does not
implement.

The problem cases come from a debugger client sending
qTBuffer, qTStatus, qSearch, qSupported.

The incorrect response from the gdbstub leads the debugger clients to
not function correctly.  Recent versions of gdb will not detach correctly as a result of this behavior.
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>
Signed-off-by: NDongdong Deng <dongdong.deng@windriver.com>

Without this patch the "ll" linked-list traversal command won't
terminate when you hit q/Q.
Signed-off-by: NMartin Hicks <mort@sgi.com>
Signed-off-by: NJason Wessel <jason.wessel@windriver.com>

With commits 08677214 and 59be5a8e, alloc_bootmem()/free_bootmem() and
friends use the early_res functions for memory management when
NO_BOOTMEM is enabled. This patch adds the kmemleak calls in the
corresponding code paths for bootmem allocations.
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
Acked-by: NPekka Enberg <penberg@cs.helsinki.fi>
Acked-by: NYinghai Lu <yinghai@kernel.org>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: stable@kernel.org

We should initialize the module dynamic debug datastructures
only after determining that the module is not loaded yet. This
fixes a bug that introduced in 2.6.35-rc2, where when a trying
to load a module twice, we also load it's dynamic printing data
twice which causes all sorts of nasty issues. Also handle
the dynamic debug cleanup later on failure.
Signed-off-by: NYehuda Sadeh <yehuda@hq.newdream.net>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (removed a #ifdef)
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Commit 0224cf4c (sched: Intoduce get_cpu_iowait_time_us())
broke things by not making sure preemption was indeed disabled
by the callers of nr_iowait_cpu() which took the iowait value of
the current cpu.

This resulted in a heap of preempt warnings. Cure this by making
nr_iowait_cpu() take a cpu number and fix up the callers to pass
in the right number.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Arjan van de Ven <arjan@infradead.org>
Cc: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Cc: Rafael J. Wysocki <rjw@sisk.pl>
Cc: Maxim Levitsky <maximlevitsky@gmail.com>
Cc: Len Brown <len.brown@intel.com>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Jiri Slaby <jslaby@suse.cz>
Cc: linux-pm@lists.linux-foundation.org
LKML-Reference: <1277968037.1868.120.camel@laptop>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

futex_find_get_task is currently used (through lookup_pi_state) from two
contexts, futex_requeue and futex_lock_pi_atomic.  None of the paths
looks it needs the credentials check, though.  Different (e)uids
shouldn't matter at all because the only thing that is important for
shared futex is the accessibility of the shared memory.

The credentail check results in glibc assert failure or process hang (if
glibc is compiled without assert support) for shared robust pthread
mutex with priority inheritance if a process tries to lock already held
lock owned by a process with a different euid:

pthread_mutex_lock.c:312: __pthread_mutex_lock_full: Assertion `(-(e)) != 3 || !robust' failed.

The problem is that futex_lock_pi_atomic which is called when we try to
lock already held lock checks the current holder (tid is stored in the
futex value) to get the PI state.  It uses lookup_pi_state which in turn
gets task struct from futex_find_get_task.  ESRCH is returned either
when the task is not found or if credentials check fails.

futex_lock_pi_atomic simply returns if it gets ESRCH.  glibc code,
however, doesn't expect that robust lock returns with ESRCH because it
should get either success or owner died.
Signed-off-by: NMichal Hocko <mhocko@suse.cz>
Acked-by: NDarren Hart <dvhltc@us.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Nick Piggin <npiggin@suse.de>
Cc: Alexey Kuznetsov <kuznet@ms2.inr.ac.ru>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When crashkernel is not enabled, "echo 0 > /sys/kernel/kexec_crash_size"
OOPSes the kernel in crash_shrink_memory.  This happens when
crash_shrink_memory tries to release the 'crashk_res' resource which are
not reserved.  Also value of "/sys/kernel/kexec_crash_size" shows as 1,
which should be 0.

This patch fixes the OOPS in crash_shrink_memory and shows
"/sys/kernel/kexec_crash_size" as 0 when crash kernel memory is not
reserved.
Signed-off-by: NPavan Naregundi <pavan@linux.vnet.ibm.com>
Reviewed-by: NWANG Cong <xiyou.wangcong@gmail.com>
Cc: Simon Horman <horms@verge.net.au>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

GCC 4.4.1 on ARM has been observed to replace the while loop in
sched_avg_update with a call to uldivmod, resulting in the
following build failure at link-time:

kernel/built-in.o: In function `sched_avg_update':
 kernel/sched.c:1261: undefined reference to `__aeabi_uldivmod'
 kernel/sched.c:1261: undefined reference to `__aeabi_uldivmod'
make: *** [.tmp_vmlinux1] Error 1

This patch introduces a fake data hazard to the loop body to
prevent the compiler optimising the loop away.
Signed-off-by: NWill Deacon <will.deacon@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NPeter Zijlstra <peterz@infradead.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Russell King <rmk@arm.linux.org.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: <stable@kernel.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Because cgroup_fork() is ran before sched_fork() [ from copy_process() ]
and the child's pid is not yet visible the child is pinned to its
cgroup. Therefore we can silence this warning.

A nicer solution would be moving cgroup_fork() to right after
dup_task_struct() and exclude PF_STARTING from task_subsys_state().
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: NLi Zefan <lizf@cn.fujitsu.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

The task_group() function returns a pointer that must be protected
by either RCU, the ->alloc_lock, or the cgroup lock (see the
rcu_dereference_check() in task_subsys_state(), which is invoked by
task_group()).  The wake_affine() function currently does none of these,
which means that a concurrent update would be within its rights to free
the structure returned by task_group().  Because wake_affine() uses this
structure only to compute load-balancing heuristics, there is no reason
to acquire either of the two locks.

Therefore, this commit introduces an RCU read-side critical section that
starts before the first call to task_group() and ends after the last use
of the "tg" pointer returned from task_group().  Thanks to Li Zefan for
pointing out the need to extend the RCU read-side critical section from
that proposed by the original patch.
Signed-off-by: NDaniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: NPaul E. McKenney <paulmck@linux.vnet.ibm.com>

Commit e7097159 ("sched: Optimize unused cgroup configuration") introduced
an imbalanced scheduling bug.

If we do not use CGROUP, function update_h_load won't update h_load. When the
system has a large number of tasks far more than logical CPU number, the
incorrect cfs_rq[cpu]->h_load value will cause load_balance() to pull too
many tasks to the local CPU from the busiest CPU. So the busiest CPU keeps
going in a round robin. That will hurt performance.

The issue was found originally by a scientific calculation workload that
developed by Yanmin. With that commit, the workload performance drops
about 40%.

 CPU  before    after

 00   : 2       : 7
 01   : 1       : 7
 02   : 11      : 6
 03   : 12      : 7
 04   : 6       : 6
 05   : 11      : 7
 06   : 10      : 6
 07   : 12      : 7
 08   : 11      : 6
 09   : 12      : 6
 10   : 1       : 6
 11   : 1       : 6
 12   : 6       : 6
 13   : 2       : 6
 14   : 2       : 6
 15   : 1       : 6
Reviewed-by: NYanmin zhang <yanmin.zhang@intel.com>
Signed-off-by: NAlex Shi <alex.shi@intel.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1276754893.9452.5442.camel@debian>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Chris Wedgwood reports that 39c0cbe2 (sched: Rate-limit nohz) causes a
serial console regression, unresponsiveness, and indeed it does. The
reason is that the nohz code is skipped even when the tick was already
stopped before the nohz_ratelimit(cpu) condition changed.

Move the nohz_ratelimit() check to the other conditions which prevent
long idle sleeps.
Reported-by: NChris Wedgwood <cw@f00f.org>
Tested-by: NBrian Bloniarz <bmb@athenacr.com>
Signed-off-by: NMike Galbraith <efault@gmx.de>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Greg KH <gregkh@suse.de>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: OGAWA Hirofumi <hirofumi@mail.parknet.co.jp>
Cc: Jef Driesen <jefdriesen@telenet.be>
LKML-Reference: <1276790557.27822.516.camel@twins>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

With the addition of the code to shrink the kernel tracepoint
infrastructure, we lost kprobes being traced by perf. The reason
is that I tested if the "tp_event->class->perf_probe" existed before
enabling it. This prevents "ftrace only" events (like the function
trace events) from being enabled by perf.

Unfortunately, kprobe events do not use perf_probe. This causes
kprobes to be missed by perf. To fix this, we add the test to
see if "tp_event->class->reg" exists as well as perf_probe.

Normal trace events have only "perf_probe" but no "reg" function,
and kprobes and syscalls have the "reg" but no "perf_probe".
The ftrace unique events do not have either, so this is a valid
test. If a kprobe or syscall is not to be probed by perf, the
"reg" function is called anyway, and will return a failure and
prevent perf from probing it.
Reported-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Tested-by: NSrikar Dronamraju <srikar@linux.vnet.ibm.com>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NSteven Rostedt <rostedt@goodmis.org>

Saving platform non-volatile state may be required for suspend to RAM as
well as hibernation. Move it to more generic code.
Signed-off-by: NMatthew Garrett <mjg@redhat.com>
Acked-by: NRafael J. Wysocki <rjw@sisk.pl>
Tested-by: NMaxim Levitsky <maximlevitsky@gmail.com>
Signed-off-by: NLen Brown <len.brown@intel.com>

The set_type() function can change the chip implementation when the
trigger mode changes. That might result in using an non-initialized
irq chip when called from __setup_irq() or when called via
set_irq_type() on an already enabled irq. 

The set_irq_type() function should not be called on an enabled irq,
but because we forgot to put a check into it, we have a bunch of users
which grew the habit of doing that and it never blew up as the
function is serialized via desc->lock against all users of desc->chip
and they never hit the non-initialized irq chip issue.

The easy fix for the __setup_irq() issue would be to move the
irq_chip_set_defaults(desc->chip) call after the trigger setting to
make sure that a chip change is covered.

But as we have already users, which do the type setting after
request_irq(), the safe fix for now is to call irq_chip_set_defaults()
from __irq_set_trigger() when desc->set_type() changed the irq chip.

It needs a deeper analysis whether we should refuse to change the chip
on an already enabled irq, but that'd be a large scale change to fix
all the existing users. So that's neither stable nor 2.6.35 material.
Reported-by: NEsben Haabendal <eha@doredevelopment.dk>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: linuxppc-dev <linuxppc-dev@ozlabs.org>
Cc: stable@kernel.org

PROVE_RCU has a few issues with the cpu_cgroup because the scheduler
typically holds rq->lock around the css rcu derefs but the generic
cgroup code doesn't (and can't) know about that lock.

Provide means to add extra checks to the css dereference and use that
in the scheduler to annotate its users.

The addition of rq->lock to these checks is correct because the
cgroup_subsys::attach() method takes the rq->lock for each task it
moves, therefore by holding that lock, we ensure the task is pinned to
the current cgroup and the RCU derefence is valid.

That leaves one genuine race in __sched_setscheduler() where we used
task_group() without holding any of the required locks and thus raced
with the cgroup code. Solve this by moving the check under the
appropriate lock.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Frederic reported that frequency driven swevents didn't work properly
and even caused a division-by-zero error.

It turns out there are two bugs, the division-by-zero comes from a
failure to deal with that in perf_calculate_period().

The other was more interesting and turned out to be a wrong comparison
in perf_adjust_period(). The comparison was between an s64 and u64 and
got implicitly converted to an unsigned comparison. The problem is
that period_left is typically < 0, so it ended up being always true.

Cure this by making the local period variables s64.
Reported-by: NFrederic Weisbecker <fweisbec@gmail.com>
Tested-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: <stable@kernel.org>
LKML-Reference: <new-submission>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Problem: it's hard to avoid an init routine stumbling over a
request_module these days.  And it's not clear it's always a bad idea:
for example, a module like kvm with dynamic dependencies on kvm-intel
or kvm-amd would be neater if it could simply request_module the right
one.

In this particular case, it's libcrc32c:

	libcrc32c_mod_init
	 crypto_alloc_shash
	  crypto_alloc_tfm
	   crypto_find_alg
	    crypto_alg_mod_lookup
	     crypto_larval_lookup
	      request_module

If another module is waiting inside resolve_symbol() for libcrc32c to
finish initializing (ie. bne2 depends on libcrc32c) then it does so
holding the module lock, and our request_module() can't make progress
until that is released.

Waiting inside resolve_symbol() without the lock isn't all that hard:
we just need to pass the -EBUSY up the call chain so we can sleep
where we don't hold the lock.  Error reporting is a bit trickier: we
need to copy the name of the unfinished module before releasing the
lock.

Other notes:
1) This also fixes a theoretical issue where a weak dependency would allow
   symbol version mismatches to be ignored.
2) We rename use_module to ref_module to make life easier for the only
   external user (the out-of-tree ksplice patches).
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Tim Abbot <tabbott@ksplice.com>
Tested-by: NBrandon Philips <bphilips@suse.de>

It disabled preempt so it was "safe", but nothing stops another module
slipping in before this module is added to the global list now we don't
hold the lock the whole time.

So we check this just after we check for duplicate modules, and just
before we put the module in the global list.

(find_symbol finds symbols in coming and going modules, too).
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

I think Rusty may have made the lock a bit _too_ finegrained there, and
didn't add it to some places that needed it. It looks, for example, like
PATCH 1/2 actually drops the lock in places where it's needed
("find_module()" is documented to need it, but now load_module() didn't
hold it at all when it did the find_module()).

Rather than adding a new "module_loading" list, I think we should be able
to just use the existing "modules" list, and just fix up the locking a
bit.

In fact, maybe we could just move the "look up existing module" a bit
later - optimistically assuming that the module doesn't exist, and then
just undoing the work if it turns out that we were wrong, just before
adding ourselves to the list.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Kay Sievers <kay.sievers@vrfy.org> reports that we still have some
contention over module loading which is slowing boot.

Linus also disliked a previous "drop lock and regrab" patch to fix the
bne2 "gave up waiting for init of module libcrc32c" message.

This is more ambitious: we only grab the lock where we need it.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Brandon Philips <brandon@ifup.org>
Cc: Kay Sievers <kay.sievers@vrfy.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>

These were placed in the header in ef665c1a to get the various
SYSFS/MODULE config combintations to compile.

That may have been necessary then, but it's not now.  These functions
are all local to module.c.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Randy Dunlap <randy.dunlap@oracle.com>

This means a little extra work, but is more logical: we don't put
anything in sysfs until we're about to put the module into the
global list an parse its parameters.

This also gives us a logical place to put duplicate module detection
in the next patch.
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>

Linus changed the structure, and luckily this didn't compile any more.
Reported-by: NStephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Cc: Jason Wessel <jason.wessel@windriver.com>
Cc: Martin Hicks <mort@sgi.com>

When adding a module that depends on another one, we used to create a
one-way list of "modules_which_use_me", so that module unloading could
see who needs a module.

It's actually quite simple to make that list go both ways: so that we
not only can see "who uses me", but also see a list of modules that are
"used by me".

In fact, we always wanted that list in "module_unload_free()": when we
unload a module, we want to also release all the other modules that are
used by that module.  But because we didn't have that list, we used to
first iterate over all modules, and then iterate over each "used by me"
list of that module.

By making the list two-way, we simplify module_unload_free(), and it
allows for some trivial fixes later too.
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (cleaned & rebased)

The commit 80b5184c ("kernel/: convert cpu
notifier to return encapsulate errno value") changed the return value of
cpu notifier callbacks.

Those callbacks don't return NOTIFY_BAD on failures anymore.  But there
are a few callbacks which are called directly at init time and checking
the return value.

I forgot to change BUG_ON checking by the direct callers in the commit.
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Child groups should have a greater depth than their parents.  Prior to
this change, the parent would incorrectly report zero memory usage for
child cgroups when use_hierarchy is enabled.

test script:
  mount -t cgroup none /cgroups -o memory
  cd /cgroups
  mkdir cg1

  echo 1 > cg1/memory.use_hierarchy
  mkdir cg1/cg11

  echo $$ > cg1/cg11/tasks
  dd if=/dev/zero of=/tmp/foo bs=1M count=1

  echo
  echo CHILD
  grep cache cg1/cg11/memory.stat

  echo
  echo PARENT
  grep cache cg1/memory.stat

  echo $$ > tasks
  rmdir cg1/cg11 cg1
  cd /
  umount /cgroups

Using fae9c791, a recent patch that changed alloc_css_id() depth computation,
the parent incorrectly reports zero usage:
  root@ubuntu:~# ./test
  1+0 records in
  1+0 records out
  1048576 bytes (1.0 MB) copied, 0.0151844 s, 69.1 MB/s

  CHILD
  cache 1048576
  total_cache 1048576

  PARENT
  cache 0
  total_cache 0

With this patch, the parent correctly includes child usage:
  root@ubuntu:~# ./test
  1+0 records in
  1+0 records out
  1048576 bytes (1.0 MB) copied, 0.0136827 s, 76.6 MB/s

  CHILD
  cache 1052672
  total_cache 1052672

  PARENT
  cache 0
  total_cache 1052672
Signed-off-by: NGreg Thelen <gthelen@google.com>
Acked-by: NPaul Menage <menage@google.com>
Acked-by: NKAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Acked-by: NLi Zefan <lizf@cn.fujitsu.com>
Cc: <stable@kernel.org>		[2.6.34.x]
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

task_struct->pesonality is "unsigned int", but sys_personality() paths use
"unsigned long pesonality".  This means that every assignment or
comparison is not right.  In particular, if this argument does not fit
into "unsigned int" __set_personality() changes the caller's personality
and then sys_personality() returns -EINVAL.

Turn this argument into "unsigned int" and avoid overflows.  Obviously,
this is the user-visible change, we just ignore the upper bits.  But this
can't break the sane application.

There is another thing which can confuse the poorly written applications.
User-space thinks that this syscall returns int, not long.  This means
that the returned value can be negative and look like the error code.  But
note that libc won't be confused and thus errno won't be set, and with
this patch the user-space can never get -1 unless sys_personality() really
fails.  And, most importantly, the negative RET != -1 is only possible if
that app previously called personality(RET).
Pointed-out-by: NWenming Zhang <wezhang@redhat.com>
Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NOleg Nesterov <oleg@redhat.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Frederic reported that because swevents handling doesn't disable IRQs
anymore, we can get a recursion of perf_adjust_period(), once from
overflow handling and once from the tick.

If both call ->disable, we get a double hlist_del_rcu() and trigger
a LIST_POISON2 dereference.

Since we don't actually need to stop/start a swevent to re-programm
the hardware (lack of hardware to program), simply nop out these
callbacks for the swevent pmu.
Reported-by: NFrederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1275557609.27810.35218.camel@twins>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

This changes the interface to be based on bytes instead. The API
matches that of F_SETPIPE_SZ in that it rounds up the passed in
size so that the resulting page array is a power-of-2 in size.

The proc file is renamed to /proc/sys/fs/pipe-max-size to
reflect this change.
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>

In commit e9fb7631 ("cpu-hotplug: introduce cpu_notify(),
__cpu_notify(), cpu_notify_nofail()") the new helper functions access
cpu_chain.  As a result, it shouldn't be marked __cpuinitdata (via
section mismatch warning).

Alternatively, the helper functions should be forced inline, or marked
__ref or __cpuinit.  In the meantime, this patch silences the warning
the trivial way.
Signed-off-by: NDaniel J Blueman <daniel.blueman@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Mike reports that since e9e9250b (sched: Scale down cpu_power due to RT
tasks), wake_affine() goes funny on RT tasks due to them still having a
!0 weight and wake_affine() still subtracts that from the rq weight.

Since nobody should be using se->weight for RT tasks, set the value to
zero. Also, since we now use ->cpu_power to normalize rq weights to
account for RT cpu usage, add that factor into the imbalance computation.
Reported-by: NMike Galbraith <efault@gmx.de>
Tested-by: NMike Galbraith <efault@gmx.de>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
LKML-Reference: <1275316109.27810.22969.camel@twins>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Rafael sees a sometimes crash at precpu_modfree from kernel/module.c; it
only occurred with another (since-reverted) patch, but that patch simply
changed timing to uncover this bug, it was otherwise unrelated.

The comment about the mod being freed is self-explanatory, but neither
Tejun nor I read it.  This bug was introduced in 259354de, after it
had previously been fixed in 6e2b7574.  How embarrassing.
Reported-by: N"Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: NRusty Russell <rusty@rustcorp.com.au>
Embarrassingly-Acked-by: NTejun Heo <tj@kernel.org>
Cc: Masami Hiramatsu <mhiramat@redhat.com>
Tested-by: N"Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Fix blktrace.c kernel-doc warnings:
 Warning(kernel/trace/blktrace.c:858): No description found for parameter 'ignore'
 Warning(kernel/trace/blktrace.c:890): No description found for parameter 'ignore'
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Cc: Jens Axboe <jens.axboe@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20100529114507.c466fc1e.randy.dunlap@oracle.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>