Commit Graph

9791 Commits

Author SHA1 Message Date
Linus Torvalds
fa7eadab4b Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  mutex: Fix optimistic spinning vs. BKL
2010-05-30 12:35:15 -07:00
Linus Torvalds
bc7d352c5e Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf tui: Fix last use_browser problem related to .perfconfig
  perf symbols: Add the build id cache to the vmlinux path
  perf tui: Reset use_browser if stdout is not a tty
  ring-buffer: Move zeroing out excess in page to ring buffer code
  ring-buffer: Reset "real_end" when page is filled
2010-05-30 12:35:01 -07:00
Rafael J. Wysocki
e9a5f426b8 CPU: Avoid using unititialized error variable in disable_nonboot_cpus()
If there's only one CPU online when disable_nonboot_cpus() is called,
the error variable will not be initialized and that may lead to
erroneous behavior.  Fix this issue by initializing error in
disable_nonboot_cpus() as appropriate.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-30 09:06:00 -07:00
Linus Torvalds
35926ff5fb Revert "cpusets: randomize node rotor used in cpuset_mem_spread_node()"
This reverts commit 0ac0c0d0f8, which
caused cross-architecture build problems for all the wrong reasons.
IA64 already added its own version of __node_random(), but the fact is,
there is nothing architectural about the function, and the original
commit was just badly done. Revert it, since no fix is forthcoming.

Requested-by: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-30 09:00:03 -07:00
Linus Torvalds
b612a05537 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client:
  ceph: clean up on forwarded aborted mds request
  ceph: fix leak of osd authorizer
  ceph: close out mds, osd connections before stopping auth
  ceph: make lease code DN specific
  fs/ceph: Use ERR_CAST
  ceph: renew auth tickets before they expire
  ceph: do not resend mon requests on auth ticket renewal
  ceph: removed duplicated #includes
  ceph: avoid possible null dereference
  ceph: make mds requests killable, not interruptible
  sched: add wait_for_completion_killable_timeout
2010-05-30 08:56:39 -07:00
Sage Weil
0aa12fb439 sched: add wait_for_completion_killable_timeout
Add missing _killable_timeout variant for wait_for_completion that will
return when a timeout expires or the task is killed.

CC: Ingo Molnar <mingo@elte.hu>
CC: Andreas Herrmann <andreas.herrmann3@amd.com>
CC: Thomas Gleixner <tglx@linutronix.de>
CC: Mike Galbraith <efault@gmx.de>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Sage Weil <sage@newdream.net>
2010-05-29 09:12:30 -07:00
Linus Torvalds
29d03fa12b Merge branch 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'timers-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  posix_timer: Fix error path in timer_create
  hrtimer: Avoid double seqlock
  timers: Move local variable into else section
  timers: Fix slack calculation really
2010-05-28 10:16:27 -07:00
Al Viro
ea635c64e0 Fix racy use of anon_inode_getfd() in perf_event.c
once anon_inode_getfd() is called, you can't expect *anything* about
struct file that descriptor points to - another thread might be doing
whatever it likes with descriptor table at that point.

Cc: stable <stable@kernel.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-27 22:03:08 -04:00
Linus Torvalds
c5617b200a Merge branch 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip
* 'perf-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (61 commits)
  tracing: Add __used annotation to event variable
  perf, trace: Fix !x86 build bug
  perf report: Support multiple events on the TUI
  perf annotate: Fix up usage of the build id cache
  x86/mmiotrace: Remove redundant instruction prefix checks
  perf annotate: Add TUI interface
  perf tui: Remove annotate from popup menu after failure
  perf report: Don't start the TUI if -D is used
  perf: Fix getline undeclared
  perf: Optimize perf_tp_event_match()
  perf: Remove more code from the fastpath
  perf: Optimize the !vmalloc backed buffer
  perf: Optimize perf_output_copy()
  perf: Fix wakeup storm for RO mmap()s
  perf-record: Share per-cpu buffers
  perf-record: Remove -M
  perf: Ensure that IOC_OUTPUT isn't used to create multi-writer buffers
  perf, trace: Optimize tracepoints by using per-tracepoint-per-cpu hlist to track events
  perf, trace: Optimize tracepoints by removing IRQ-disable from perf/tracepoint interaction
  perf tui: Allow disabling the TUI on a per command basis in ~/.perfconfig
  ...
2010-05-27 15:23:47 -07:00
Andrey Vagin
45e0fffc8a posix_timer: Fix error path in timer_create
Move CLOCK_DISPATCH(which_clock, timer_create, (new_timer)) after all
posible EFAULT erros.

*_timer_create may allocate/get resources.
(for example posix_cpu_timer_create does get_task_struct)

[ tglx: fold the remove crappy comment patch into this ]

Signed-off-by: Andrey Vagin <avagin@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: <stable@kernel.org>
Reviewed-by: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-05-27 22:38:15 +02:00
Linus Torvalds
00b9b0af58 Avoid warning when CPU hotplug isn't enabled
Commit e9fb7631eb ("cpu-hotplug: introduce cpu_notify(),
__cpu_notify(), cpu_notify_nofail()") also introduced this annoying
warning:

  kernel/cpu.c:157: warning: 'cpu_notify_nofail' defined but not used

when CONFIG_HOTPLUG_CPU wasn't set.

So move that helper inside the #ifdef CONFIG_HOTPLUG_CPU region, and
simplify it while at it.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 10:32:08 -07:00
Lee Schermerhorn
3dd6b5fb43 numa: in-kernel profiling: use cpu_to_mem() for per cpu allocations
In kernel profiling requires that we be able to allocate "local" memory
for each cpu.  Use "cpu_to_mem()" instead of "cpu_to_node()" to support
memoryless nodes.

Depends on the "numa_mem_id()" patch.

Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Tejun Heo <tj@kernel.org>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Nick Piggin <npiggin@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Eric Whitney <eric.whitney@hp.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: <linux-arch@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:57 -07:00
Anton Blanchard
5b530fc183 panic: call console_verbose() in panic
Most distros turn the console verbosity down and that means a backtrace
after a panic never makes it to the console.  I assume we haven't seen
this because a panic is often preceeded by an oops which will have called
console_verbose.  There are however a lot of places we call panic
directly, and they are broken.

Use console_verbose like we do in the oops path to ensure a directly
called panic will print a backtrace.

Signed-off-by: Anton Blanchard <anton@samba.org>
Acked-by: Greg Kroah-Hartman <gregkh@suse.de>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:53 -07:00
Oleg Nesterov
f106eee100 pids: fix fork_idle() to setup ->pids correctly
copy_process(pid => &init_struct_pid) doesn't do attach_pid/etc.

It shouldn't, but this means that the idle threads run with the wrong
pids copied from the caller's task_struct. In x86 case the caller is
either kernel_init() thread or keventd.

In particular, this means that after the series of cpu_up/cpu_down an
idle thread (which never exits) can run with .pid pointing to nowhere.

Change fork_idle() to initialize idle->pids[] correctly. We only set
.pid = &init_struct_pid but do not add .node to list, INIT_TASK() does
the same for the boot-cpu idle thread (swapper).

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Eric Biederman <ebiederm@xmission.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Mathias Krause <Mathias.Krause@secunet.com>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:52 -07:00
Hedi Berriche
72680a191b pids: increase pid_max based on num_possible_cpus
On a system with a substantial number of processors, the early default
pid_max of 32k will not be enough.  A system with 1664 CPU's, there are
25163 processes started before the login prompt.  It's estimated that with
2048 CPU's we will pass the 32k limit.  With 4096, we'll reach that limit
very early during the boot cycle, and processes would stall waiting for an
available pid.

This patch increases the early maximum number of pids available, and
increases the minimum number of pids that can be set during runtime.

[akpm@linux-foundation.org: fix warnings]
Signed-off-by: Hedi Berriche <hedi@sgi.com>
Signed-off-by: Mike Travis <travis@sgi.com>
Signed-off-by: Robin Holt <holt@sgi.com>
Acked-by: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Pavel Machek <pavel@ucw.cz>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Greg KH <gregkh@suse.de>
Cc: Rik van Riel <riel@redhat.com>
Cc: John Stoffel <john@stoffel.org>
Cc: Jack Steiner <steiner@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:51 -07:00
Lai Jiangshan
79a6cdeb7e cpuhotplug: do not need cpu_hotplug_begin() when CONFIG_HOTPLUG_CPU=n
Since when CONFIG_HOTPLUG_CPU=n, get_online_cpus() do nothing, so we don't
need cpu_hotplug_begin() either.

This patch moves cpu_hotplug_begin()/cpu_hotplug_done() into the code
block of CONFIG_HOTPLUG_CPU=y.

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
Cc: Gautham R Shenoy <ego@in.ibm.com>
Cc: Ingo Molnar <mingo@elte.hu>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:48 -07:00
Akinobu Mita
80b5184cc5 kernel/: convert cpu notifier to return encapsulate errno value
By the previous modification, the cpu notifier can return encapsulate
errno value.  This converts the cpu notifiers for kernel/*.c

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:48 -07:00
Akinobu Mita
e6bde73b07 cpu-hotplug: return better errno on cpu hotplug failure
Currently, onlining or offlining a CPU failure by one of the cpu notifiers
error always cause -EINVAL error.  (i.e.  writing 0 or 1 to
/sys/devices/system/cpu/cpuX/online gets EINVAL)

To get better error reporting rather than always getting -EINVAL, This
changes cpu_notify() to return -errno value with notifier_to_errno() and
fix the callers.  Now that cpu notifiers can return encapsulate errno
value.

Currently, all cpu hotplug notifiers return NOTIFY_OK, NOTIFY_BAD, or
NOTIFY_DONE.  So cpu_notify() can returns 0 or -EPERM with this change for
now.

(notifier_to_errno(NOTIFY_OK) == 0, notifier_to_errno(NOTIFY_DONE) == 0,
notifier_to_errno(NOTIFY_BAD) == -EPERM)

Forthcoming patches convert several cpu notifiers to return encapsulate
errno value with notifier_from_errno().

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:47 -07:00
Akinobu Mita
e9fb7631eb cpu-hotplug: introduce cpu_notify(), __cpu_notify(), cpu_notify_nofail()
No functional change.  These are just wrappers of
raw_cpu_notifier_call_chain.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:47 -07:00
Oleg Nesterov
b3ac022cb9 proc: turn signal_struct->count into "int nr_threads"
No functional changes, just s/atomic_t count/int nr_threads/.

With the recent changes this counter has a single user, get_nr_threads()
And, none of its callers need the really accurate number of threads, not
to mention each caller obviously races with fork/exit.  It is only used to
report this value to the user-space, except first_tid() uses it to avoid
the unnecessary while_each_thread() loop in the unlikely case.

It is a bit sad we need a word in struct signal_struct for this, perhaps
we can change get_nr_threads() to approximate the number of threads using
signal->live and kill ->nr_threads later.

[akpm@linux-foundation.org: coding-style fixes]
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:47 -07:00
Oleg Nesterov
5089a97680 proc_sched_show_task(): use get_nr_threads()
Trivial, use get_nr_threads() helper to read signal->count which we are
going to change.

Like other callers, proc_sched_show_task() doesn't need the exactly
precise nr_threads.

David said:

: Note that get_nr_threads() isn't completely equivalent (it can return 0
: where proc_sched_show_task() will display a 1).  But I don't think this
: should be a problem.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:47 -07:00
Oleg Nesterov
6e1be45aa6 check_unshare_flags: kill the bogus CLONE_SIGHAND/sig->count check
check_unshare_flags(CLONE_SIGHAND) adds CLONE_THREAD to *flags_ptr if the
task is multithreaded to ensure unshare_thread() will fail.

Not only this is a bit strange way to return the error, this is absolutely
meaningless.  If signal->count > 1 then sighand->count must be also > 1,
and unshare_sighand() will fail anyway.

In fact, all CLONE_THREAD/SIGHAND/VM checks inside sys_unshare() do not
look right.  Fortunately this code doesn't really work anyway.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Veaceslav Falico <vfalico@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:47 -07:00
Oleg Nesterov
97101eb41d exit: move taskstats_tgid_free() from __exit_signal() to free_signal_struct()
Move taskstats_tgid_free() from __exit_signal() to free_signal_struct().

This way signal->stats never points to nowhere and we can read ->stats
lockless.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Veaceslav Falico <vfalico@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:46 -07:00
Oleg Nesterov
a705be6b5e kill the obsolete thread_group_cputime_free() helper
Kill the empty thread_group_cputime_free() helper.  It was needed to free
the per-cpu data which we no longer have.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Veaceslav Falico <vfalico@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:46 -07:00
Oleg Nesterov
d40e48e02f exit: __exit_signal: use thread_group_leader() consistently
Cleanup:

- Add the boolean, group_dead = thread_group_leader(), for clarity.

- Do not test/set sig == NULL to detect the all-dead case, use this
  boolean.

- Pass this boolen to __unhash_process() and use it instead of another
  thread_group_leader() call which needs ->group_leader.

  This can be considered as microoptimization, but hopefully this also
  allows us do do other cleanups later.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Roland McGrath <roland@redhat.com>
Cc: Veaceslav Falico <vfalico@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:46 -07:00
Oleg Nesterov
b7b8ff6373 signals: kill the awful task_rq_unlock_wait() hack
Now that task->signal can't go away we can revert the horrible hack added
by ad474caca3 ("fix for
account_group_exec_runtime(), make sure ->signal can't be freed under
rq->lock").

And we can do more cleanups sched_stats.h/posix-cpu-timers.c later.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:46 -07:00
Oleg Nesterov
4ada856fb0 signals: clear signal->tty when the last thread exits
When the last thread exits signal->tty is freed, but the pointer is not
cleared and points to nowhere.

This is OK.  Nobody should use signal->tty lockless, and it is no longer
possible to take ->siglock.  However this looks wrong even if correct, and
the nice OOPS is better than subtle and hard to find bugs.

Change __exit_signal() to clear signal->tty under ->siglock.

Note: __exit_signal() needs more cleanups.  It should not check "sig !=
NULL" to detect the all-dead case and we have the same issues with
signal->stats.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: Peter Zijlstra <peterz@infradead.org>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:46 -07:00
Oleg Nesterov
ea6d290ca3 signals: make task_struct->signal immutable/refcountable
We have a lot of problems with accessing task_struct->signal, it can
"disappear" at any moment.  Even current can't use its ->signal safely
after exit_notify().  ->siglock helps, but it is not convenient, not
always possible, and sometimes it makes sense to use task->signal even
after this task has already dead.

This patch adds the reference counter, sigcnt, into signal_struct.  This
reference is owned by task_struct and it is dropped in
__put_task_struct().  Perhaps it makes sense to export
get/put_signal_struct() later, but currently I don't see the immediate
reason.

Rename __cleanup_signal() to free_signal_struct() and unexport it.  With
the previous changes it does nothing except kmem_cache_free().

Change __exit_signal() to not clear/free ->signal, it will be freed when
the last reference to any thread in the thread group goes away.

Note:
	- when the last thead exits signal->tty can point to nowhere, see
	  the next patch.

	- with or without this patch signal_struct->count should go away,
	  or at least it should be "int nr_threads" for fs/proc. This will
	  be addressed later.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Alan Cox <alan@linux.intel.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:46 -07:00
Oleg Nesterov
4dec2a91fd fork/exit: move tty_kref_put() outside of __cleanup_signal()
tty_kref_put() has two callsites in copy_process() paths,

	1. if copy_process() suceeds it is called before we copy
	   signal->tty from parent

	2. otherwise it is called from __cleanup_signal() under
	   bad_fork_cleanup_signal: label

In both cases tty_kref_put() is not right and unneeded because we don't
have the balancing tty_kref_get().  Fortunately, this is harmless because
this can only happen without CLONE_THREAD, and in this case signal->tty
must be NULL.

Remove tty_kref_put() from copy_process() and __cleanup_signal(), and
change another caller of __cleanup_signal(), __exit_signal(), to call
tty_kref_put() by hand.

I hope this change makes sense by itself, but it is also needed to make
->signal refcountable.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Alan Cox <alan@linux.intel.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Greg KH <greg@kroah.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:46 -07:00
Oleg Nesterov
d30fda3551 posix-cpu-timers: avoid "task->signal != NULL" checks
Preparation to make task->signal immutable, no functional changes.

posix-cpu-timers.c checks task->signal != NULL to ensure this task is
alive and didn't pass __exit_signal().  This is correct but we are going
to change the lifetime rules for ->signal and never reset this pointer.

Change the code to check ->sighand instead, it doesn't matter which
pointer we check under tasklist, they both are cleared simultaneously.

As Roland pointed out, some of these changes are not strictly needed and
probably it makes sense to revert them later, when ->signal will be pinned
to task_struct.  But this patch tries to ensure the subsequent changes in
fork/exit can't make any visible impact on posix cpu timers.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:46 -07:00
Oleg Nesterov
4a59994297 exit: avoid sig->count in __exit_signal() to detect the group-dead case
Change __exit_signal() to check thread_group_leader() instead of
atomic_dec_and_test(&sig->count).  This must be equivalent, the group
leader must be released only after all other threads have exited and
passed __exit_signal().

Henceforth sig->count is not actually used, except in fs/proc for
get_nr_threads/etc.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:46 -07:00
Oleg Nesterov
d344193a05 exit: avoid sig->count in de_thread/__exit_signal synchronization
de_thread() and __exit_signal() use signal_struct->count/notify_count for
synchronization.  We can simplify the code and use ->notify_count only.
Instead of comparing these two counters, we can change de_thread() to set
->notify_count = nr_of_sub_threads, then change __exit_signal() to
dec-and-test this counter and notify group_exit_task.

Note that __exit_signal() checks "notify_count > 0" just for symmetry with
exit_notify(), we could just check it is != 0.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:46 -07:00
Oleg Nesterov
09faef11df exit: change zap_other_threads() to count sub-threads
Change zap_other_threads() to return the number of other sub-threads found
on ->thread_group list.

Other changes are cosmetic:

	- change the code to use while_each_thread() helper

	- remove the obsolete comment about SIGKILL/SIGSTOP

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:46 -07:00
Oleg Nesterov
9c33916844 exit: exit_notify() can trust signal->notify_count < 0
signal_struct->count in its current form must die.

- it has no reasons to be atomic_t

- it looks like a reference counter, but it is not

- otoh, we really need to make task->signal refcountable, just look at
  the extremely ugly task_rq_unlock_wait() called from __exit_signals().

- we should change the lifetime rules for task->signal, it should be
  pinned to task_struct.  We have a lot of code which can be simplified
  after that.

- it is not needed!  while the code is correct, any usage of this
  counter is artificial, except fs/proc uses it correctly to show the
  number of threads.

This series removes the usage of sig->count from exit pathes.

This patch:

Now that Veaceslav changed copy_signal() to use zalloc(), exit_notify()
can just check notify_count < 0 to ensure the execing sub-threads needs
the notification from us.  No need to do other checks, notify_count != 0
must always mean ->group_exit_task != NULL is waiting for us.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Cc: Veaceslav Falico <vfalico@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:45 -07:00
Oleg Nesterov
04b1c384fb call_usermodehelper: UMH_WAIT_EXEC ignores kernel_thread() failure
UMH_WAIT_EXEC should report the error if kernel_thread() fails, like
UMH_WAIT_PROC does.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:45 -07:00
Oleg Nesterov
d47419cd96 call_usermodehelper: simplify/fix UMH_NO_WAIT case
__call_usermodehelper(UMH_NO_WAIT) has 2 problems:

	- if kernel_thread() fails, call_usermodehelper_freeinfo()
	  is not called.

	- for unknown reason UMH_NO_WAIT has UMH_WAIT_PROC logic,
	  we spawn yet another thread which waits until the user
	  mode application exits.

Change the UMH_NO_WAIT code to use ____call_usermodehelper() instead of
wait_for_helper(), and do call_usermodehelper_freeinfo() unconditionally.
We can rely on CLONE_VFORK, do_fork(CLONE_VFORK) until the child exits or
execs.

With or without this patch UMH_NO_WAIT does not report the error if
kernel_thread() fails, this is correct since the caller doesn't wait for
result.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:45 -07:00
Oleg Nesterov
7d64224217 wait_for_helper: SIGCHLD from user-space can lead to use-after-free
1. wait_for_helper() calls allow_signal(SIGCHLD) to ensure the child
   can't autoreap itself.

   However, this means that a spurious SIGCHILD from user-space can
   set TIF_SIGPENDING and:

   	- kernel_thread() or sys_wait4() can fail due to signal_pending()

   	- worse, wait4() can fail before ____call_usermodehelper() execs
   	  or exits. In this case the caller may kfree(subprocess_info)
   	  while the child still uses this memory.

   Change the code to use SIG_DFL instead of magic "(void __user *)2"
   set by allow_signal(). This means that SIGCHLD won't be delivered,
   yet the child won't autoreap itsefl.

   The problem is minor, only root can send a signal to this kthread.

2. If sys_wait4(&ret) fails it doesn't populate "ret", in this case
   wait_for_helper() reports a random value from uninitialized var.

   With this patch sys_wait4() should never fail, but still it makes
   sense to initialize ret = -ECHILD so that the caller can notice
   the problem.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:45 -07:00
Oleg Nesterov
363da4022c call_usermodehelper: no need to unblock signals
____call_usermodehelper() correctly calls flush_signal_handlers() to set
SIG_DFL, but sigemptyset(->blocked) and recalc_sigpending() are not
needed.

This kthread was forked by workqueue thread, all signals must be unblocked
and ignored, no pending signal is possible.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:45 -07:00
Oleg Nesterov
c70a626d3e umh: creds: kill subprocess_info->cred logic
Now that nobody ever changes subprocess_info->cred we can kill this member
and related code.  ____call_usermodehelper() always runs in the context of
freshly forked kernel thread, it has the proper ->cred copied from its
parent kthread, keventd.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:45 -07:00
Oleg Nesterov
685bfd2c48 umh: creds: convert call_usermodehelper_keys() to use subprocess_info->init()
call_usermodehelper_keys() uses call_usermodehelper_setkeys() to change
subprocess_info->cred in advance.  Now that we have info->init() we can
change this code to set tgcred->session_keyring in context of execing
kernel thread.

Note: since currently call_usermodehelper_keys() is never called with
UMH_NO_WAIT, call_usermodehelper_keys()->key_get() and umh_keys_cleanup()
are not really needed, we could rely on install_session_keyring_to_cred()
which does key_get() on success.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: David Howells <dhowells@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:45 -07:00
Neil Horman
898b374af6 exec: replace call_usermodehelper_pipe with use of umh init function and resolve limit
The first patch in this series introduced an init function to the
call_usermodehelper api so that processes could be customized by caller.
This patch takes advantage of that fact, by customizing the helper in
do_coredump to create the pipe and set its core limit to one (for our
recusrsion check).  This lets us clean up the previous uglyness in the
usermodehelper internals and factor call_usermodehelper out entirely.
While I'm at it, we can also modify the helper setup to look for a core
limit value of 1 rather than zero for our recursion check

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:44 -07:00
Neil Horman
a06a4dc3a0 kmod: add init function to usermodehelper
About 6 months ago, I made a set of changes to how the core-dump-to-a-pipe
feature in the kernel works.  We had reports of several races, including
some reports of apps bypassing our recursion check so that a process that
was forked as part of a core_pattern setup could infinitely crash and
refork until the system crashed.

We fixed those by improving our recursion checks.  The new check basically
refuses to fork a process if its core limit is zero, which works well.

Unfortunately, I've been getting grief from maintainer of user space
programs that are inserted as the forked process of core_pattern.  They
contend that in order for their programs (such as abrt and apport) to
work, all the running processes in a system must have their core limits
set to a non-zero value, to which I say 'yes'.  I did this by design, and
think thats the right way to do things.

But I've been asked to ease this burden on user space enough times that I
thought I would take a look at it.  The first suggestion was to make the
recursion check fail on a non-zero 'special' number, like one.  That way
the core collector process could set its core size ulimit to 1, and enable
the kernel's recursion detection.  This isn't a bad idea on the surface,
but I don't like it since its opt-in, in that if a program like abrt or
apport has a bug and fails to set such a core limit, we're left with a
recursively crashing system again.

So I've come up with this.  What I've done is modify the
call_usermodehelper api such that an extra parameter is added, a function
pointer which will be called by the user helper task, after it forks, but
before it exec's the required process.  This will give the caller the
opportunity to get a call back in the processes context, allowing it to do
whatever it needs to to the process in the kernel prior to exec-ing the
user space code.  In the case of do_coredump, this callback is ues to set
the core ulimit of the helper process to 1.  This elimnates the opt-in
problem that I had above, as it allows the ulimit for core sizes to be set
to the value of 1, which is what the recursion check looks for in
do_coredump.

This patch:

Create new function call_usermodehelper_fns() and allow it to assign both
an init and cleanup function, as we'll as arbitrary data.

The init function is called from the context of the forked process and
allows for customization of the helper process prior to calling exec.  Its
return code gates the continuation of the process, or causes its exit.
Also add an arbitrary data pointer to the subprocess_info struct allowing
for data to be passed from the caller to the new process, and the
subsequent cleanup process

Also, use this patch to cleanup the cleanup function.  It currently takes
an argp and envp pointer for freeing, which is ugly.  Lets instead just
make the subprocess_info structure public, and pass that to the cleanup
and init routines

Signed-off-by: Neil Horman <nhorman@tuxdriver.com>
Reviewed-by: Oleg Nesterov <oleg@redhat.com>
Cc: Andi Kleen <andi@firstfloor.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:44 -07:00
Oleg Nesterov
065add3941 signals: check_kill_permission(): don't check creds if same_thread_group()
Andrew Tridgell reports that aio_read(SIGEV_SIGNAL) can fail if the
notification from the helper thread races with setresuid(), see
http://samba.org/~tridge/junkcode/aio_uid.c

This happens because check_kill_permission() doesn't permit sending a
signal to the task with the different cred->xids.  But there is not any
security reason to check ->cred's when the task sends a signal (private or
group-wide) to its sub-thread.  Whatever we do, any thread can bypass all
security checks and send SIGKILL to all threads, or it can block a signal
SIG and do kill(gettid(), SIG) to deliver this signal to another
sub-thread.  Not to mention that CLONE_THREAD implies CLONE_VM.

Change check_kill_permission() to avoid the credentials check when the
sender and the target are from the same thread group.

Also, move "cred = current_cred()" down to avoid calling get_current()
twice.

Note: David Howells pointed out we could relax this even more, the
CLONE_SIGHAND (without CLONE_THREAD) case probably does not need
these checks too.

Roland said:
: The glibc (libpthread) that does set*id across threads has
: been in use for a while (2.3.4?), probably in distro's using kernels as old
: or older than any active -stable streams.  In the race in question, this
: kernel bug is breaking valid POSIX application expectations.

Reported-by: Andrew Tridgell <tridge@samba.org>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Jakub Jelinek <jakub@redhat.com>
Cc: James Morris <jmorris@namei.org>
Cc: Roland McGrath <roland@redhat.com>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Cc: <stable@kernel.org>		[all kernel versions]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:44 -07:00
Oleg Nesterov
e0129ef91e ptrace: PTRACE_GETFDPIC: fix the unsafe usage of child->mm
Now that Mike Frysinger unified the FDPIC ptrace code, we can fix the
unsafe usage of child->mm in ptrace_request(PTRACE_GETFDPIC).

We have the reference to task_struct, and ptrace_check_attach() verified
the tracee is stopped.  But nothing can protect from SIGKILL after that,
we must not assume child->mm != NULL.

Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Acked-by: Mike Frysinger <vapier.adi@gmail.com>
Acked-by: David Howells <dhowells@redhat.com>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Greg Ungerer <gerg@snapgear.com>
Acked-by: Roland McGrath <roland@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:44 -07:00
Mike Frysinger
9c1a125921 ptrace: unify FDPIC implementations
The Blackfin/FRV/SuperH guys all have the same exact FDPIC ptrace code in
their arch handlers (since they were probably copied & pasted).  Since
these ptrace interfaces are an arch independent aspect of the FDPIC code,
unify them in the common ptrace code so new FDPIC ports don't need to copy
and paste this fundamental stuff yet again.

Signed-off-by: Mike Frysinger <vapier@gentoo.org>
Acked-by: Roland McGrath <roland@redhat.com>
Acked-by: David Howells <dhowells@redhat.com>
Acked-by: Paul Mundt <lethal@linux-sh.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:44 -07:00
Jack Steiner
0ac0c0d0f8 cpusets: randomize node rotor used in cpuset_mem_spread_node()
Some workloads that create a large number of small files tend to assign
too many pages to node 0 (multi-node systems).  Part of the reason is that
the rotor (in cpuset_mem_spread_node()) used to assign nodes starts at
node 0 for newly created tasks.

This patch changes the rotor to be initialized to a random node number of
the cpuset.

[akpm@linux-foundation.org: fix layout]
[Lee.Schermerhorn@hp.com: Define stub numa_random() for !NUMA configuration]
Signed-off-by: Jack Steiner <steiner@sgi.com>
Signed-off-by: Lee Schermerhorn <lee.schermerhorn@hp.com>
Cc: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Paul Menage <menage@google.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Robin Holt <holt@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:44 -07:00
Jack Steiner
6adef3ebe5 cpusets: new round-robin rotor for SLAB allocations
We have observed several workloads running on multi-node systems where
memory is assigned unevenly across the nodes in the system.  There are
numerous reasons for this but one is the round-robin rotor in
cpuset_mem_spread_node().

For example, a simple test that writes a multi-page file will allocate
pages on nodes 0 2 4 6 ...  Odd nodes are skipped.  (Sometimes it
allocates on odd nodes & skips even nodes).

An example is shown below.  The program "lfile" writes a file consisting
of 10 pages.  The program then mmaps the file & uses get_mempolicy(...,
MPOL_F_NODE) to determine the nodes where the file pages were allocated.
The output is shown below:

	# ./lfile
	 allocated on nodes: 2 4 6 0 1 2 6 0 2

There is a single rotor that is used for allocating both file pages & slab
pages.  Writing the file allocates both a data page & a slab page
(buffer_head).  This advances the RR rotor 2 nodes for each page
allocated.

A quick confirmation seems to confirm this is the cause of the uneven
allocation:

	# echo 0 >/dev/cpuset/memory_spread_slab
	# ./lfile
	 allocated on nodes: 6 7 8 9 0 1 2 3 4 5

This patch introduces a second rotor that is used for slab allocations.

Signed-off-by: Jack Steiner <steiner@sgi.com>
Acked-by: Christoph Lameter <cl@linux-foundation.org>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Paul Menage <menage@google.com>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Robin Holt <holt@sgi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:44 -07:00
Kirill A. Shutemov
907860ed38 cgroups: make cftype.unregister_event() void-returning
Since we are unable to handle an error returned by
cftype.unregister_event() properly, let's make the callback
void-returning.

mem_cgroup_unregister_event() has been rewritten to be a "never fail"
function.  On mem_cgroup_usage_register_event() we save old buffer for
thresholds array and reuse it in mem_cgroup_usage_unregister_event() to
avoid allocation.

Signed-off-by: Kirill A. Shutemov <kirill@shutemov.name>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Phil Carmody <ext-phil.2.carmody@nokia.com>
Cc: Balbir Singh <balbir@linux.vnet.ibm.com>
Cc: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Paul Menage <menage@google.com>
Cc: Li Zefan <lizf@cn.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-05-27 09:12:44 -07:00
Stanislaw Gruszka
174bd1994e hrtimer: Avoid double seqlock
hrtimer_get_softirq_time() has it's own xtime lock protection, so it's
safe to use plain __current_kernel_time() and avoid the double seqlock
loop.

Signed-off-by: Stanislaw Gruszka <stf_xl@wp.pl>
LKML-Reference: <20100525214912.GA1934@r2bh72.net.upc.cz>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-05-26 16:15:37 +02:00
Thomas Gleixner
2abfb9e1d4 timers: Move local variable into else section
Fix nit-picking coding style detail.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
2010-05-26 16:07:13 +02:00