mm: mempolicy: Let vma_merge and vma_split handle vma->vm_policy linkages

commit 05f144a0d5c2207a0349348127f996e104ad7404 upstream.

Dave Jones' system call fuzz testing tool "trinity" triggered the
following bug error with slab debugging enabled

    =============================================================================
    BUG numa_policy (Not tainted): Poison overwritten
    -----------------------------------------------------------------------------

    INFO: 0xffff880146498250-0xffff880146498250. First byte 0x6a instead of 0x6b
    INFO: Allocated in mpol_new+0xa3/0x140 age=46310 cpu=6 pid=32154
     __slab_alloc+0x3d3/0x445
     kmem_cache_alloc+0x29d/0x2b0
     mpol_new+0xa3/0x140
     sys_mbind+0x142/0x620
     system_call_fastpath+0x16/0x1b
    INFO: Freed in __mpol_put+0x27/0x30 age=46268 cpu=6 pid=32154
     __slab_free+0x2e/0x1de
     kmem_cache_free+0x25a/0x260
     __mpol_put+0x27/0x30
     remove_vma+0x68/0x90
     exit_mmap+0x118/0x140
     mmput+0x73/0x110
     exit_mm+0x108/0x130
     do_exit+0x162/0xb90
     do_group_exit+0x4f/0xc0
     sys_exit_group+0x17/0x20
     system_call_fastpath+0x16/0x1b
    INFO: Slab 0xffffea0005192600 objects=27 used=27 fp=0x          (null) flags=0x20000000004080
    INFO: Object 0xffff880146498250 @offset=592 fp=0xffff88014649b9d0

This implied a reference counting bug and the problem happened during
mbind().

mbind() applies a new memory policy to a range and uses mbind_range() to
merge existing VMAs or split them as necessary.  In the event of splits,
mpol_dup() will allocate a new struct mempolicy and maintain existing
reference counts whose rules are documented in
Documentation/vm/numa_memory_policy.txt .

The problem occurs with shared memory policies.  The vm_op->set_policy
increments the reference count if necessary and split_vma() and
vma_merge() have already handled the existing reference counts.
However, policy_vma() screws it up by replacing an existing
vma->vm_policy with one that potentially has the wrong reference count
leading to a premature free.  This patch removes the damage caused by
policy_vma().

With this patch applied Dave's trinity tool runs an mbind test for 5
minutes without error.  /proc/slabinfo reported that there are no
numa_policy or shared_policy_node objects allocated after the test
completed and the shared memory region was deleted.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Cc: Dave Jones <davej@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Stephen Wilson <wilsons@start.ca>
Cc: Christoph Lameter <cl@linux.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
md: using GFP_NOIO to allocate bio for flush request

commit b5e1b8cee7ad58a15d2fa79bcd7946acb592602d upstream.

A flush request is usually issued in transaction commit code path, so
using GFP_KERNEL to allocate memory for flush request bio falls into
the classic deadlock issue.

This is suitable for any -stable kernel to which it applies as it
avoids a possible deadlock.

Signed-off-by: Shaohua Li <shli@fusionio.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Add missing call to uart_update_timeout()

commit 8b979f7c6bf13a57e7b6002f1175312a44773960 upstream.

This patch fixes a problem reported here:
http://article.gmane.org/gmane.linux.ports.arm.kernel/155242/match=auart

Signed-off-by: Lothar Waßmann <LW@KARO-electronics.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
8250.c: less than 2400 baud fix.

commit f9a9111b540fd67db5dab332f4b83d86c90e27b1 upstream.

We noticed that we were loosing data at speed less than 2400 baud.
It turned out our (TI16750 compatible) uart with 64 byte outgoing fifo
was truncated to 16 byte (bit 5 sets fifo len) when modifying the fcr
reg.
The input code still fills the buffer with 64 bytes if I remember
correctly and thus data is lost.
Our fix was to remove whiping of the fcr content and just add the
TRIGGER_1 which we want for latency.
I can't see why this would not work on less than 2400 always, for all
uarts ...
Otherwise one would have to make sure the filling of the fifo re-checks
the current state of available fifo size (urrk).

Signed-off-by: Christian Melki <christian.melki@ericsson.se>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
8250_pci: fix pch uart matching

commit aaa10eb1d0034eccc096f583fe308f0921617598 upstream.

The rules used to make 8250_pci "ignore" the PCH uarts are lacking pci subids
entries, preventing it to match and thus is breaking serial port support for
theses systems.

This has been tested on a nanoETXexpress-TT, which has a specifici uart clock.

Tested-by: Erwan Velu <Erwan.Velu@zodiacaerospace.com>
[stable@: please apply to 3.0-stable, 3.2-stable and 3.3-stable]
Signed-off-by: Arnaud Patard <apatard@hupstream.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tty: Allow uart_register/unregister/register

commit 1e66cded334e6cea596c72f6f650eec351b1e959 upstream.

This is legitimate but because we don't clear the drv->state pointer in the
unregister code causes a bogus BUG().

Resolves-bug: https://bugzilla.kernel.org/show_bug.cgi?id=42880
Signed-off-by: Alan Cox <alan@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>