Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

Signed-off-by: NAl Viro <viro@zeniv.linux.org.uk>

By modyfing genlmsg_put() to take a genl_family and by adding
genlmsg_put_reply() the process of constructing the netlink
and generic netlink headers is simplified.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Acked-by: NPaul Moore <paul.moore@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NThomas Graf <tgraf@suug.ch>
Acked-by: NPaul Moore <paul.moore@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Account for the netlink message header size directly in nlmsg_new()
instead of relying on the caller calculate it correctly.

Replaces error handling of message construction functions when
constructing notifications with bug traps since a failure implies
a bug in calculating the size of the skb.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Acked-by: NPaul Moore <paul.moore@hp.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Show the drivers, which belong to the module:
  $ ls -l /sys/module/usbcore/drivers/
  hub -> ../../../bus/usb/drivers/hub
  usb -> ../../../bus/usb/drivers/usb
  usbfs -> ../../../bus/usb/drivers/usbfs
Signed-off-by: NKay Sievers <kay.sievers@vrfy.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

The return value of create_write_pipe()/create_read_pipe() should be
checked by IS_ERR().
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This fixes a problem with gcc4 mis-compiling the stack unwind code under
-Os, which resulted in 'stuck' messages whenever an assembly routine was
encountered.

(The second hunk is trivial cleanup.)
Signed-off-by: NJan Beulich <jbeulich@novell.com>

Introduce spin_lock_irqsave_nested(); implementation from:
 http://lkml.org/lkml/2006/6/1/122
Patch from:
 http://lkml.org/lkml/2006/9/13/258

[akpm@osdl.org: two compile fixes]
Signed-off-by: NArjan van de Ven <arjan@linux.intel.com>
Signed-off-by: NJiri Kosina <jikos@jikos.cz>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The return value of copy_process() should be checked by IS_ERR().
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This reverts commit f72fa707, and solves
the problem that it tried to fix by simply making "__do_IRQ()" call the
note_interrupt() function without the lock held, the way everybody else
does.

It should be noted that all interrupt handling code must never allow the
descriptor actors to be entered "recursively" (that's why we do all the
magic IRQ_PENDING stuff in the first place), so there actually is
exclusion at that much higher level, even in the absense of locking.
Acked-by: NVivek Goyal <vgoyal@in.ibm.com>
Acked-by: NPavel Emelianov <xemul@openvz.org>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Adrian Bunk <bunk@stusta.de>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

lockdep got confused by certain locks in modules:

 INFO: trying to register non-static key.
 the code is fine but needs lockdep annotation.
 turning off the locking correctness validator.

 Call Trace:
  [<ffffffff8026f40d>] dump_trace+0xaa/0x3f2
  [<ffffffff8026f78f>] show_trace+0x3a/0x60
  [<ffffffff8026f9d1>] dump_stack+0x15/0x17
  [<ffffffff802abfe8>] __lock_acquire+0x724/0x9bb
  [<ffffffff802ac52b>] lock_acquire+0x4d/0x67
  [<ffffffff80267139>] rt_spin_lock+0x3d/0x41
  [<ffffffff8839ed3f>] :ip_conntrack:__ip_ct_refresh_acct+0x131/0x174
  [<ffffffff883a1334>] :ip_conntrack:udp_packet+0xbf/0xcf
  [<ffffffff8839f9af>] :ip_conntrack:ip_conntrack_in+0x394/0x4a7
  [<ffffffff8023551f>] nf_iterate+0x41/0x7f
  [<ffffffff8025946a>] nf_hook_slow+0x64/0xd5
  [<ffffffff802369a2>] ip_rcv+0x24e/0x506
  [...]

Steven Rostedt found the bug: static_obj() check did not take
PERCPU_ENOUGH_ROOM into account, so in-module DEFINE_PER_CPU-area locks
were triggering this message.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I got an oops when booting 2.6.19-rc5-mm1 on my ia64 machine.

Below is the log.

Oops 11012296146944 [1]
Modules linked in: binfmt_misc dm_mirror dm_multipath dm_mod thermal processor f
an container button sg eepro100 e100 mii

Pid: 0, CPU 0, comm:              swapper
psr : 0000121008022038 ifs : 800000000000040b ip  : [<a0000001000e1411>]    Not
tainted
ip is at __do_IRQ+0x371/0x3e0
unat: 0000000000000000 pfs : 000000000000040b rsc : 0000000000000003
rnat: 656960155aa56aa5 bsps: a00000010058b890 pr  : 656960155aa55a65
ldrs: 0000000000000000 ccv : 0000000000000000 fpsr: 0009804c0270033f
csd : 0000000000000000 ssd : 0000000000000000
b0  : a0000001000e1390 b6  : a0000001005beac0 b7  : e00000007f01aa00
f6  : 000000000000000000000 f7  : 0ffe69090000000000000
f8  : 1000a9090000000000000 f9  : 0ffff8000000000000000
f10 : 1000a908ffffff6f70000 f11 : 1003e0000000000000909
r1  : a000000100fbbff0 r2  : 0000000000010002 r3  : 0000000000010001
r8  : fffffffffffbffff r9  : a000000100bd8060 r10 : a000000100dd83b8
r11 : fffffffffffeffff r12 : a000000100bcbbb0 r13 : a000000100bc4000
r14 : 0000000000010000 r15 : 0000000000010000 r16 : a000000100c01aa8
r17 : a000000100d2c350 r18 : 0000000000000000 r19 : a000000100d2c300
r20 : a000000100c01a88 r21 : 0000000080010100 r22 : a000000100c01ac0
r23 : a0000001000108e0 r24 : e000000477980004 r25 : 0000000000000000
r26 : 0000000000000000 r27 : e00000000913400c r28 : e0000004799ee51c
r29 : e0000004778b87f0 r30 : a000000100d2c300 r31 : a00000010005c7e0

Call Trace:
 [<a000000100014600>] show_stack+0x40/0xa0
                                sp=a000000100bcb760 bsp=a000000100bc4f40
 [<a000000100014f00>] show_regs+0x840/0x880
                                sp=a000000100bcb930 bsp=a000000100bc4ee8
 [<a000000100037fb0>] die+0x250/0x320
                                sp=a000000100bcb930 bsp=a000000100bc4ea0
 [<a00000010005e5f0>] ia64_do_page_fault+0x8d0/0xa20
                                sp=a000000100bcb950 bsp=a000000100bc4e50
 [<a00000010000caa0>] ia64_leave_kernel+0x0/0x290
                                sp=a000000100bcb9e0 bsp=a000000100bc4e50
 [<a0000001000e1410>] __do_IRQ+0x370/0x3e0
                                sp=a000000100bcbbb0 bsp=a000000100bc4df0
 [<a000000100011f50>] ia64_handle_irq+0x170/0x220
                                sp=a000000100bcbbb0 bsp=a000000100bc4dc0
 [<a00000010000caa0>] ia64_leave_kernel+0x0/0x290
                                sp=a000000100bcbbb0 bsp=a000000100bc4dc0
 [<a000000100012390>] ia64_pal_call_static+0x90/0xc0
                                sp=a000000100bcbd80 bsp=a000000100bc4d78
 [<a000000100015630>] default_idle+0x90/0x160
                                sp=a000000100bcbd80 bsp=a000000100bc4d58
 [<a000000100014290>] cpu_idle+0x1f0/0x440
                                sp=a000000100bcbe20 bsp=a000000100bc4d18
 [<a000000100009980>] rest_init+0xc0/0xe0
                                sp=a000000100bcbe20 bsp=a000000100bc4d00
 [<a0000001009f8ea0>] start_kernel+0x6a0/0x6c0
                                sp=a000000100bcbe20 bsp=a000000100bc4ca0
 [<a0000001000089f0>] __end_ivt_text+0x6d0/0x6f0
                                sp=a000000100bcbe30 bsp=a000000100bc4c00
 <0>Kernel panic - not syncing: Aiee, killing interrupt handler!

The root cause is that some irq_chip variables, especially ia64_msi_chip,
initiate their memeber end to point to NULL. __do_IRQ doesn't check
if irq_chip->end is null and just calls it after processing the interrupt.

As irq_chip->end is called at many places, so I fix it by reinitiating
irq_chip->end to dummy_irq_chip.end, e.g., a noop function.
Signed-off-by: NZhang Yanmin <yanmin.zhang@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This reverts commit 0130b0b3.

Sergey Vlasov points out (and Vadim Lobanov concurs) that the bug it was
supposed to fix must be some unrelated memory corruption, and the "fix"
actually causes more problems:

  "However, the new code does not look safe in all cases.  If some other
   task has opened more files while dup_fd() released oldf->file_lock, the
   new code will update open_files to the new larger value.  But newf was
   allocated with the old smaller value of open_files, therefore subsequent
   accesses to newf may try to write into unallocated memory."

so revert it.

Cc: Sharyathi Nagesh <sharyath@in.ibm.com>
Cc: Sergey Vlasov <vsu@altlinux.ru>
Cc: Vadim Lobanov <vlobanov@speakeasy.net>
Cc: Andrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

When we get a mismatch between handlers on the same IRQ, all we get is "IRQ
handler type mismatch for IRQ n".  Let's print the name of the
presently-registered handler with which we got the mismatch.

Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

While testing kernel on machine with "irqpoll" option I've caught such a
lockup:

	__do_IRQ()
	   spin_lock(&desc->lock);
           desc->chip->ack(); /* IRQ is ACKed */
	note_interrupt()
	misrouted_irq()
	handle_IRQ_event()
           if (...)
	      local_irq_enable_in_hardirq();
	/* interrupts are enabled from now */
	...
	__do_IRQ() /* same IRQ we've started from */
	   spin_lock(&desc->lock); /* LOCKUP */

Looking at misrouted_irq() code I've found that a potential deadlock like
this can also take place:

1CPU:
__do_IRQ()
   spin_lock(&desc->lock); /* irq = A */
misrouted_irq()
   for (i = 1; i < NR_IRQS; i++) {
      spin_lock(&desc->lock); /* irq = B */
      if (desc->status & IRQ_INPROGRESS) {

2CPU:
__do_IRQ()
   spin_lock(&desc->lock); /* irq = B */
misrouted_irq()
   for (i = 1; i < NR_IRQS; i++) {
      spin_lock(&desc->lock); /* irq = A */
      if (desc->status & IRQ_INPROGRESS) {

As the second lock on both CPUs is taken before checking that this irq is
being handled in another processor this may cause a deadlock.  This issue
is only theoretical.

I propose the attached patch to fix booth problems: when trying to handle
misrouted IRQ active desc->lock may be unlocked.
Acked-by: NIngo Molnar <mingo@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

On running the Stress Test on machine for more than 72 hours following
error message was observed.

0:mon> e
cpu 0x0: Vector: 300 (Data Access) at [c00000007ce2f7f0]
    pc: c000000000060d90: .dup_fd+0x240/0x39c
    lr: c000000000060d6c: .dup_fd+0x21c/0x39c
    sp: c00000007ce2fa70
   msr: 800000000000b032
   dar: ffffffff00000028
 dsisr: 40000000
  current = 0xc000000074950980
  paca    = 0xc000000000454500
    pid   = 27330, comm = bash

0:mon> t
[c00000007ce2fa70] c000000000060d28 .dup_fd+0x1d8/0x39c (unreliable)
[c00000007ce2fb30] c000000000060f48 .copy_files+0x5c/0x88
[c00000007ce2fbd0] c000000000061f5c .copy_process+0x574/0x1520
[c00000007ce2fcd0] c000000000062f88 .do_fork+0x80/0x1c4
[c00000007ce2fdc0] c000000000011790 .sys_clone+0x5c/0x74
[c00000007ce2fe30] c000000000008950 .ppc_clone+0x8/0xc

The problem is because of race window.  When if(expand) block is executed in
dup_fd unlocking of oldf->file_lock give a window for fdtable in oldf to be
modified.  So actual open_files in oldf may not match with open_files
variable.

Cc: Vadim Lobanov <vlobanov@speakeasy.net>
Cc: <stable@kernel.org>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Since it is becoming clear that there are just enough users of the binary
sysctl interface that completely removing the binary interface from the kernel
will not be an option for foreseeable future, we need to find a way to address
the sysctl maintenance issues.

The basic problem is that sysctl requires one central authority to allocate
sysctl numbers, or else conflicts and ABI breakage occur.  The proc interface
to sysctl does not have that problem, as names are not densely allocated.

By not terminating a sysctl table until I have neither a ctl_name nor a
procname, it becomes simple to add sysctl entries that don't show up in the
binary sysctl interface.  Which allows people to avoid allocating a binary
sysctl value when not needed.

I have audited the kernel code and in my reading I have not found a single
sysctl table that wasn't terminated by a completely zero filled entry.  So
this change in behavior should not affect anything.

I think this mechanism eases the pain enough that combined with a little
disciple we can solve the reoccurring sysctl ABI breakage.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Acked-by: NAlan Cox <alan@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Don't warn about libpthread's access to kernel.version.  When it receives
-ENOSYS it will read /proc/sys/kernel/version.

If anything else shows up print the sysctl number string.
Signed-off-by: NEric W. Biederman <ebiederm@xmission.com>
Cc: Cal Peake <cp@absolutedigital.net>
Cc: Alan Cox <alan@redhat.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Make the delayacct lock irqsave; this avoids the possible deadlock where
an interrupt is taken while holding the delayacct lock which needs to
take the delayacct lock.
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Cpu-hotplug locking has a minor race case caused because of setting the
variable "recursive" to NULL *after* releasing the cpu_bitmask_lock in the
function unlock_cpu_hotplug,instead of doing so before releasing the
cpu_bitmask_lock.

This was the cause of most of the recent false spurious lock_cpu_unlock
warnings.

This should fix the problem reported by Martin Lorenz reported in
http://lkml.org/lkml/2006/10/29/127.

Thanks to Srinivasa DS for pointing it out.
Signed-off-by: NGautham R Shenoy <ego@in.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

The previous commit (45c18b0b, aka "Fix
unlikely (but possible) race condition on task->user access") fixed a
potential oops due to __sigqueue_alloc() getting its "user" pointer out
of sync with switch_user(), and accessing a user pointer that had been
de-allocated on another CPU.

It still left another (much less serious) problem, where a concurrent
__sigqueue_alloc and swich_user could cause sigqueue_alloc to do signal
pending reference counting for a _different_ user than the one it then
actually ended up using.  No oops, but we'd end up with the wrong signal
accounting.

Another case of Oleg's eagle-eyes picking up the problem.

This is trivially fixed by just making sure we load whichever "user"
structure we decide to use (it doesn't matter _which_ one we pick, we
just need to pick one) just once.
Acked-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

There's a possible race condition when doing a "switch_uid()" from one
user to another, which could race with another thread doing a signal
allocation and looking at the old thread ->user pointer as it is freed.

This explains an oops reported by Lukasz Trabinski:
	http://permalink.gmane.org/gmane.linux.kernel/462241

We fix this by delaying the (reference-counted) freeing of the user
structure until the thread signal handler lock has been released, so
that we know that the signal allocation has either seen the new value or
has properly incremented the reference count of the old one.

Race identified by Oleg Nesterov.

Cc: Lukasz Trabinski <lukasz@wsisiz.edu.pl>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This is needed on bigendian 64bit architectures.
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Acked-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Add a swsusp debugging mode.  This does everything that's needed for a suspend
except for actually suspending.  So we can look in the log messages and work
out a) what code is being slow and b) which drivers are misbehaving.

(1)
# echo testproc > /sys/power/disk
# echo disk > /sys/power/state

This should turn off the non-boot CPU, freeze all processes, wait for 5
seconds and then thaw the processes and the CPU.

(2)
# echo test > /sys/power/disk
# echo disk > /sys/power/state

This should turn off the non-boot CPU, freeze all processes, shrink
memory, suspend all devices, wait for 5 seconds, resume the devices etc.

Cc: Pavel Machek <pavel@ucw.cz>
Cc: Stefan Seyfried <seife@suse.de>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Apparently FUTEX_FD is unfixably racy and nothing uses it (or if it does, it
shouldn't).

Add a warning printk, give any remaining users six months to migrate off it.

Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Acked-by: NThomas Gleixner <tglx@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

printk_ratelimit() has global state which makes it not useful for callers
which wish to perform ratelimiting at a particular frequency.

Add a printk_timed_ratelimit() which utilises caller-provided state storage to
permit more flexibility.

This function can in fact be used for things other than printk ratelimiting
and is perhaps poorly named.

Cc: Ulrich Drepper <drepper@redhat.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

If there are no listeners, taskstats_exit_send() just returns because
taskstats_exit_alloc() didn't allocate *tidstats.  This is wrong, each
sub-thread should do fill_tgid_exit() on exit, otherwise its ->delays is
not recorded in ->signal->stats and lost.

Q: We don't send TASKSTATS_TYPE_AGGR_TGID when single-threaded process
exits.  Is it good?  How can the listener figure out that it was actually a
process exit, not sub-thread?
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Balbir Singh <balbir@in.ibm.com>
Acked-by: NShailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Paranoid fix. The task can free its ->mm after the 'if (p->mm)' check.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

For ndiswrapper, don't set the module->taints flags, just set the kernel
global tainted flag.  This should allow ndiswrapper to continue to use GPL
symbols.
Signed-off-by: NRandy Dunlap <randy.dunlap@oracle.com>
Cc: Florin Malita <fmalita@gmail.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

prepare_reply() adds GENL_HDRLEN to the payload (genlmsg_total_size()),
but then it does genlmsg_put()->nlmsg_put().  This means we forget to
reserve a room for 'struct nlmsghdr'.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Thomas Graf <tgraf@suug.ch>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

'return genlmsg_cancel()' in taskstats_user_cmd/taskstats_exit_send
potentially leaks a skb.  Unless we pass 'rep_skb' to the netlink layer
we own sk_buff.  This means we should always do kfree_skb() on failure.

[ Thomas acked and pointed out missing return value in original version ]
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Acked-by: NThomas Graf <tgraf@suug.ch>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

This patch (as812) changes the kerneldoc comments explaining the return
values from queue_work(), queue_delayed_work(), and
queue_delayed_work_on().  The updated comments explain more accurately the
meaning of the return code and avoid suggesting that a 0 value means the
routine was unsuccessful.
Signed-off-by: NAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

_cpu_down() acquires `workqueue_mutex' on its process, but doen't release it
if __cpu_disable() fails.
Signed-off-by: NSatoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

I notice that the code which implements adjtime clears the time_adjust
value before using it.  The attached patch makes the obvious fix.
Acked-by: NRoman Zippel <zippel@linux-m68k.org>
Signed-off-by: NJim Houston <jim.houston@ccur.com>
Cc: John Stultz <johnstul@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

fill_tgid() should skip not only an already exited group leader.  If the
task has ->exit_state != 0 it already did exit_notify(), so it also did
fill_tgid_exit()->delayacct_add_tsk(->signal->stats) and we should skip it
to avoid a double accounting.

This patch doesn't close the race completely, but it cleanups the code.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

Remove tasklist_lock from taskstats.c. find_task_by_pid() is rcu-safe.
->siglock allows us to traverse subthread without tasklist.

Q: delay accounting looks wrong to me.  If sub-thread has already called
taskstats_exit_send() but didn't call release_task(self) yet it will be
accounted twice.  The window is big.  No?
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

signal_struct is (mostly) protected by ->sighand->siglock, I think we don't
need ->taskstats_lock to protect ->stats.  This also allows us to simplify the
locking in fill_tgid().
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

taskstats_tgid_free() is called on copy_process's error path. This is wrong.

	IF (clone_flags & CLONE_THREAD)
		We should not clear ->signal->taskstats, current uses it,
		it probably has a valid accumulated info.
	ELSE
		taskstats_tgid_init() set ->signal->taskstats = NULL,
		there is nothing to free.

Move the callsite to __exit_signal(). We don't need any locking, entire
thread group is exiting, nobody should have a reference to soon to be
released ->signal.
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>

1. ts = timespec_sub(uptime, current->group_leader->start_time);

   It is possible that current != tsk. Probably it was supposed
   to be 'tsk->group_leader->start_time. But why we are reading
   group_leader's start_time ? This accounting is per thread,
   not per procees, I changed this to 'tsk->start_time.
   Please corect me.

2. stats->ac_ppid = (tsk->parent) ? tsk->parent->pid : 0;

   tsk->parent never == NULL, and it is unsafe to dereference it.
   Both the task and it's parent may exit after the caller unlocks
   tasklist_lock, the memory could be unmapped (DEBUG_SLAB).
   (And we should use ->real_parent->tgid in fact).

Q: I don't understand the 'if (thread_group_leader(tsk))' check.
Why it is needed ?
Signed-off-by: NOleg Nesterov <oleg@tv-sign.ru>
Cc: Shailabh Nagar <nagar@watson.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Acked-by: NJay Lan <jlan@sgi.com>
Signed-off-by: NAndrew Morton <akpm@osdl.org>
Signed-off-by: NLinus Torvalds <torvalds@osdl.org>