When looking at a performance problem on PowerPC, I noticed some awful code
generation:

c00000000051fc98:       3b 60 00 01     li      r27,1
...
c00000000051fca0:       3b 80 00 00     li      r28,0
...
c00000000051fcdc:       93 61 00 70     stw     r27,112(r1)
c00000000051fce0:       93 81 00 74     stw     r28,116(r1)
c00000000051fce4:       81 21 00 70     lwz     r9,112(r1)
c00000000051fce8:       80 01 00 74     lwz     r0,116(r1)
c00000000051fcec:       7d 29 07 b4     extsw   r9,r9
c00000000051fcf0:       7c 00 07 b4     extsw   r0,r0

c00000000051fcf4:       7c 20 04 ac     lwsync
c00000000051fcf8:       7d 60 f8 28     lwarx   r11,0,r31
c00000000051fcfc:       7c 0b 48 00     cmpw    r11,r9
c00000000051fd00:       40 c2 00 10     bne-    c00000000051fd10
c00000000051fd04:       7c 00 f9 2d     stwcx.  r0,0,r31
c00000000051fd08:       40 c2 ff f0     bne+    c00000000051fcf8
c00000000051fd0c:       4c 00 01 2c     isync

We create two constants, write them out to the stack, read them straight back
in and sign extend them. What a mess.

It turns out this bad code is a result of us defining atomic_t as a
volatile int.

We removed the volatile attribute from the powerpc atomic_t definition years
ago, but commit ea435467 (atomic_t: unify all
arch definitions) added it back in.

To dig up an old quote from Linus:

> The fact is, volatile on data structures is a bug. It's a wart in the C
> language. It shouldn't be used.
>
> Volatile accesses in *code* can be ok, and if we have "atomic_read()"
> expand to a "*(volatile int *)&(x)->value", then I'd be ok with that.
>
> But marking data structures volatile just makes the compiler screw up
> totally, and makes code for initialization sequences etc much worse.

And screw up it does :)

With the volatile removed, we see much more reasonable code generation:

c00000000051f5b8:       3b 60 00 01     li      r27,1
...
c00000000051f5c0:       3b 80 00 00     li      r28,0
...

c00000000051fc7c:       7c 20 04 ac     lwsync
c00000000051fc80:       7c 00 f8 28     lwarx   r0,0,r31
c00000000051fc84:       7c 00 d8 00     cmpw    r0,r27
c00000000051fc88:       40 c2 00 10     bne-    c00000000051fc98
c00000000051fc8c:       7f 80 f9 2d     stwcx.  r28,0,r31
c00000000051fc90:       40 c2 ff f0     bne+    c00000000051fc80
c00000000051fc94:       4c 00 01 2c     isync

Six instructions less.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

In preparation for removing volatile from the atomic_t definition, this
patch adds a volatile cast to all the atomic read functions.
Signed-off-by: Anton Blanchard <anton@samba.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
  rtnetlink: make SR-IOV VF interface symmetric
  sctp: delete active ICMP proto unreachable timer when free transport
  tcp: fix MD5 (RFC2385) support

* 'upstream' of git://ftp.linux-mips.org/pub/scm/upstream-linus:
  MIPS: Oprofile: Fix Loongson irq handler
  MIPS: N32: Use compat version for sys_ppoll.
  MIPS FPU emulator: allow Cause bits of FCSR to be writeable by ctc1

Now we have a set of nested attributes:

  IFLA_VFINFO_LIST (NESTED)
    IFLA_VF_INFO (NESTED)
      IFLA_VF_MAC
      IFLA_VF_VLAN
      IFLA_VF_TX_RATE

This allows a single set to operate on multiple attributes if desired.
Among other things, it means a dump can be replayed to set state.

The current interface has yet to be released, so this seems like
something to consider for 2.6.34.
Signed-off-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

transport may be free before ICMP proto unreachable timer expire, so
we should delete active ICMP proto unreachable timer when transport
is going away.
Signed-off-by: Wei Yongjun <yjwei@cn.fujitsu.com>
Acked-by: Vlad Yasevich <vladislav.yasevich@hp.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

TCP MD5 support uses percpu data for temporary storage. It currently
disables preemption so that same storage cannot be reclaimed by another
thread on same cpu.

We also have to make sure a softirq handler wont try to use also same
context. Various bug reports demonstrated corruptions.

Fix is to disable preemption and BH.
Reported-by: Bhaskar Dutta <bhaskie@gmail.com>
Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

    
    The interrupt enable bit for the performance counters is in the Control
    Register $24, not in the counter register.
    loongson2_perfcount_handler(), we need to use
Reported-by: Xu Hengyang <hengyang@mail.ustc.edu.cn>
Signed-off-by: Wu Zhangjin <wuzhangjin@gmail.com>
    Cc: linux-mips@linux-mips.org
    Patchwork: http://patchwork.linux-mips.org/patch/1198/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

---

    
    The sys_ppoll() takes struct 'struct timespec'. This is different for the
    N32 and N64 ABIs. Use the compat version to do the proper conversions.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
    To: linux-mips@linux-mips.org
    Patchwork: http://patchwork.linux-mips.org/patch/1210/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

---

    
    In the FPU emulator code of the MIPS, the Cause bits of the FCSR register
    are not currently writeable by the ctc1 instruction.  In odd corner cases,
    this can cause problems.  For example, a case existed where a divide-by-zero
    exception was generated by the FPU, and the signal handler attempted to
    restore the FPU registers to their state before the exception occurred.  In
    this particular setup, writing the old value to the FCSR register would
    cause another divide-by-zero exception to occur immediately.  The solution
    is to change the ctc1 instruction emulator code to allow the Cause bits of
    the FCSR register to be writeable.  This is the behaviour of the hardware
    that the code is emulating.
    
    This problem was found by Shane McDonald, but the credit for the fix goes
    to Kevin Kissell.  In Kevin's words:
    
    I submit that the bug is indeed in that ctc_op:  case of the emulator.  The
    Cause bits (17:12) are supposed to be writable by that instruction, but the
    CTC1 emulation won't let them be updated by the instruction.  I think that
    actually if you just completely removed lines 387-388 [...] things would
    work a good deal better.  At least, it would be a more accurate emulation of
    the architecturally defined FPU.  If I wanted to be really, really pedantic
    (which I sometimes do), I'd also protect the reserved bits that aren't
    necessarily writable.
Signed-off-by: Shane McDonald <mcdonald.shane@gmail.com>
    To: anemo@mba.ocn.ne.jp
    To: kevink@paralogos.com
    To: sshtylyov@mvista.com
    Patchwork: http://patchwork.linux-mips.org/patch/1205/Signed-off-by: Ralf Baechle <ralf@linux-mips.org>

---

* git://git.kernel.org/pub/scm/linux/kernel/git/mason/btrfs-unstable:
  Btrfs: check for read permission on src file in the clone ioctl

mempool_alloc() can return null in atomic case.
Signed-off-by: Denis Kirjanov <kirjanov@gmail.com>
Cc: Joern Engel <joern@logfs.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

As we were using an internal dma flushing routine, this patch changes to
the DMA API flush_kernel_dcache_page().  Driver is able to compile now.

[akpm@linux-foundation.org: flush_kernel_dcache_page() comes before kunmap_atomic()]
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
Cc: James Bottomley <James.Bottomley@HansenPartnership.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

The existing code would have allowed you to clone a file that was
only open for writing
Signed-off-by: Chris Mason <chris.mason@oracle.com>

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6:
  JFS: Free sbi memory in error path
  fs/sysv: dereferencing ERR_PTR()
  Fix double-free in logfs
  Fix the regression created by "set S_DEAD on unlink()..." commit

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 record: Add a fallback to the reference relocation symbol

I spotted the missing kfree() while removing the BKL.

[akpm@linux-foundation.org: avoid multiple returns so it doesn't happen again]
Signed-off-by: Jan Blunck <jblunck@suse.de>
Cc: Dave Kleikamp <shaggy@austin.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

I moved the dir_put_page() inside the if condition so we don't dereference
"page", if it's an ERR_PTR().
Signed-off-by: Dan Carpenter <error27@gmail.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

iput() is needed *until* we'd done successful d_alloc_root()
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

1) i_flags simply doesn't work for mount/unlink race prevention;
we may have many links to file and rm on one of those obviously
shouldn't prevent bind on top of another later on.  To fix it
right way we need to mark _dentry_ as unsuitable for mounting
upon; new flag (DCACHE_CANT_MOUNT) is protected by d_flags and
i_mutex on the inode in question.  Set it (with dont_mount(dentry))
in unlink/rmdir/etc., check (with cant_mount(dentry)) in places
in namespace.c that used to check for S_DEAD.  Setting S_DEAD
is still needed in places where we used to set it (for directories
getting killed), since we rely on it for readdir/rmdir race
prevention.

2) rename()/mount() protection has another bogosity - we unhash
the target before we'd checked that it's not a mountpoint.  Fixed.

3) ancient bogosity in pivot_root() - we locked i_mutex on the
right directory, but checked S_DEAD on the different (and wrong)
one.  Noticed and fixed.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

* master.kernel.org:/home/rmk/linux-2.6-arm:
  ARM: 6126/1: ARM mpcore_wdt: fix build failure and other fixes
  ARM: 6125/1: ARM TWD: move TWD registers to common header
  ARM: 6110/1: Fix Thumb-2 kernel builds when UACCESS_WITH_MEMCPY is enabled
  ARM: 6112/1: Use the Inner Shareable I-cache and BTB ops on ARMv7 SMP
  ARM: 6111/1: Implement read/write for ownership in the ARMv6 DMA cache ops
  ARM: 6106/1: Implement copy_to_user_page() for noMMU
  ARM: 6105/1: Fix the __arm_ioremap_caller() definition in nommu.c

Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, mrst: Don't blindly access extended config space

If the kernel is large or the profiling step small, /proc/profile
leaks data and readprofile shows silly stats, until readprofile -r
has reset the buffer: clear the prof_buffer when it is vmalloc()ed.
Signed-off-by: Hugh Dickins <hughd@google.com>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

My old address will shut down in a couple of weeks: update the tree.
Signed-off-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: Hugh Dickins <hughd@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Do not blindly access extended configuration space unless we actively
know we're on a Moorestown platform.  The fixed-size BAR capability
lives in the extended configuration space, and thus is not applicable
if the configuration space isn't appropriately sized.

This fixes booting certain VMware configurations with CONFIG_MRST=y.

Moorestown will add a fake PCI-X 266 capability to advertise the
presence of extended configuration space.
Reported-and-tested-by: Petr Vandrovec <petr@vandrovec.name>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Acked-by: Jacob Pan <jacob.jun.pan@intel.com>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
LKML-Reference: <AANLkTiltKUa3TrKR1M51eGw8FLNoQJSLT0k0_K5X3-OJ@mail.gmail.com>

Merge branch 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'x86-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  x86, cacheinfo: Turn off L3 cache index disable feature in virtualized environments
  x86, k8: Fix build error when K8_NB is disabled
  x86, amd: Check X86_FEATURE_OSVW bit before accessing OSVW MSRs
  x86: Fix fake apicid to node mapping for numa emulation

When running a quest kernel on xen we get:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000038
IP: [<ffffffff8142f2fb>] cpuid4_cache_lookup_regs+0x2ca/0x3df
PGD 0
Oops: 0000 [#1] SMP
last sysfs file:
CPU 0
Modules linked in:

Pid: 0, comm: swapper Tainted: G        W  2.6.34-rc3 #1 /HVM domU
RIP: 0010:[<ffffffff8142f2fb>]  [<ffffffff8142f2fb>] cpuid4_cache_lookup_regs+0x
2ca/0x3df
RSP: 0018:ffff880002203e08  EFLAGS: 00010046
RAX: 0000000000000000 RBX: 0000000000000003 RCX: 0000000000000060
RDX: 0000000000000000 RSI: 0000000000000040 RDI: 0000000000000000
RBP: ffff880002203ed8 R08: 00000000000017c0 R09: ffff880002203e38
R10: ffff8800023d5d40 R11: ffffffff81a01e28 R12: ffff880187e6f5c0
R13: ffff880002203e34 R14: ffff880002203e58 R15: ffff880002203e68
FS:  0000000000000000(0000) GS:ffff880002200000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
CR2: 0000000000000038 CR3: 0000000001a3c000 CR4: 00000000000006f0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
Process swapper (pid: 0, threadinfo ffffffff81a00000, task ffffffff81a44020)
Stack:
 ffffffff810d7ecb ffff880002203e20 ffffffff81059140 ffff880002203e30
<0> ffffffff810d7ec9 0000000002203e40 000000000050d140 ffff880002203e70
<0> 0000000002008140 0000000000000086 ffff880040020140 ffffffff81068b8b
Call Trace:
 <IRQ>
 [<ffffffff810d7ecb>] ? sync_supers_timer_fn+0x0/0x1c
 [<ffffffff81059140>] ? mod_timer+0x23/0x25
 [<ffffffff810d7ec9>] ? arm_supers_timer+0x34/0x36
 [<ffffffff81068b8b>] ? hrtimer_get_next_event+0xa7/0xc3
 [<ffffffff81058e85>] ? get_next_timer_interrupt+0x19a/0x20d
 [<ffffffff8142fa23>] get_cpu_leaves+0x5c/0x232
 [<ffffffff8106a7b1>] ? sched_clock_local+0x1c/0x82
 [<ffffffff8106a9a0>] ? sched_clock_tick+0x75/0x7a
 [<ffffffff8107748c>] generic_smp_call_function_single_interrupt+0xae/0xd0
 [<ffffffff8101f6ef>] smp_call_function_single_interrupt+0x18/0x27
 [<ffffffff8100a773>] call_function_single_interrupt+0x13/0x20
 <EOI>
 [<ffffffff8143c468>] ? notifier_call_chain+0x14/0x63
 [<ffffffff810295c6>] ? native_safe_halt+0xc/0xd
 [<ffffffff810114eb>] ? default_idle+0x36/0x53
 [<ffffffff81008c22>] cpu_idle+0xaa/0xe4
 [<ffffffff81423a9a>] rest_init+0x7e/0x80
 [<ffffffff81b10dd2>] start_kernel+0x40e/0x419
 [<ffffffff81b102c8>] x86_64_start_reservations+0xb3/0xb7
 [<ffffffff81b103c4>] x86_64_start_kernel+0xf8/0x107
Code: 14 d5 40 ff ae 81 8b 14 02 31 c0 3b 15 47 1c 8b 00 7d 0e 48 8b 05 36 1c 8b
 00 48 63 d2 48 8b 04 d0 c7 85 5c ff ff ff 00 00 00 00 <8b> 70 38 48 8d 8d 5c ff
 ff ff 48 8b 78 10 ba c4 01 00 00 e8 eb
RIP  [<ffffffff8142f2fb>] cpuid4_cache_lookup_regs+0x2ca/0x3df
 RSP <ffff880002203e08>
CR2: 0000000000000038
---[ end trace a7919e7f17c0a726 ]---

The L3 cache index disable feature of AMD CPUs has to be disabled if the
kernel is running as guest on top of a hypervisor because northbridge
devices are not available to the guest. Currently, this fixes a boot
crash on top of Xen. In the future this will become an issue on KVM as
well.

Check if northbridge devices are present and do not enable the feature
if there are none.

[ hpa: backported to 2.6.34 ]
Signed-off-by: Frank Arnold <frank.arnold@amd.com>
LKML-Reference: <1271945222-5283-3-git-send-email-bp@amd64.org>
Acked-by: Borislav Petkov <borislav.petkov@amd.com>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: <stable@kernel.org>

K8_NB depends on PCI and when the last is disabled (allnoconfig) we fail
at the final linking stage due to missing exported num_k8_northbridges.
Add a header stub for that.
Signed-off-by: Borislav Petkov <borislav.petkov@amd.com>
LKML-Reference: <20100503183036.GJ26107@aftab>
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Cc: <stable@kernel.org>

* 'for-linus' of git://git.infradead.org/users/eparis/notify:
  inotify: don't leak user struct on inotify release
  inotify: race use after free/double free in inotify inode marks
  inotify: clean up the inotify_add_watch out path
  Inotify: undefined reference to `anon_inode_getfd'

Manual merge to remove duplicate "select ANON_INODES" from Kconfig file

Merge branch 'davinci-fixes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-davinci

* 'davinci-fixes-for-linus-2' of git://git.kernel.org/pub/scm/linux/kernel/git/khilman/linux-davinci:
  DA830: fix USB 2.0 clock entry

DA8xx OHCI driver fails to load due to failing clk_get() call for the USB 2.0
clock. Arrange matching USB 2.0 clock by the clock name instead of the device.
(Adding another CLK() entry for "ohci.0" device won't do -- in the future I'll
also have to enable USB 2.0 clock to configure CPPI 4.1 module, in which case
I won't have any device at all.)
Signed-off-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Kevin Hilman <khilman@deeprootsystems.com>

inotify_new_group() receives a get_uid-ed user_struct and saves the
reference on group->inotify_data.user.  The problem is that free_uid() is
never called on it.

Issue seem to be introduced by 63c882a0 (inotify: reimplement inotify
using fsnotify) after 2.6.30.
Signed-off-by: Pavel Emelyanov <xemul@openvz.org>
Eric Paris <eparis@parisplace.org>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Eric Paris <eparis@redhat.com>

There is a race in the inotify add/rm watch code.  A task can find and
remove a mark which doesn't have all of it's references.  This can
result in a use after free/double free situation.

Task A					Task B
------------				-----------
inotify_new_watch()
 allocate a mark (refcnt == 1)
 add it to the idr
					inotify_rm_watch()
					 inotify_remove_from_idr()
					  fsnotify_put_mark()
					      refcnt hits 0, free
 take reference because we are on idr
 [at this point it is a use after free]
 [time goes on]
 refcnt may hit 0 again, double free

The fix is to take the reference BEFORE the object can be found in the
idr.
Signed-off-by: Eric Paris <eparis@redhat.com>
Cc: <stable@kernel.org>

inotify_add_watch explictly frees the unused inode mark, but it can just
use the generic code.  Just do that.
Signed-off-by: Eric Paris <eparis@redhat.com>

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net-2.6:
  vhost: fix barrier pairing

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/security-testing-2.6:
  mmap_min_addr check CAP_SYS_RAWIO only for write

* 'for-linus' of git://git.monstr.eu/linux-2.6-microblaze:
  microblaze: Fix module loading on system with WB cache
  microblaze: export assembly functions used by modules
  microblaze: Remove powerpc code from Microblaze port
  microblaze: Remove compilation warnings in cache macro
  microblaze: export assembly functions used by modules
  microblaze: fix get_user/put_user side-effects
  microblaze: re-enable interrupts before calling schedule

Redirecting directly to lsm, here's the patch discussed on lkml:
http://lkml.org/lkml/2010/4/22/219

The mmap_min_addr value is useful information for an admin to see without
being root ("is my system vulnerable to kernel NULL pointer attacks?") and
its setting is trivially easy for an attacker to determine by calling
mmap() in PAGE_SIZE increments starting at 0, so trying to keep it private
has no value.

Only require CAP_SYS_RAWIO if changing the value, not reading it.

Comment from Serge :

  Me, I like to write my passwords with light blue pen on dark blue
  paper, pasted on my window - if you're going to get my password, you're
  gonna get a headache.
Signed-off-by: Kees Cook <kees.cook@canonical.com>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
(cherry picked from commit 822cceec)