usb: musb: Reselect index reg in interrupt context

commit 39287076e46d2c19aaceaa6f0a44168ae4d257ec upstream.

musb INDEX register is getting modified/corrupted during temporary
un-locking in a SMP system. Set this register with proper value
after re-acquiring the lock

Scenario:
---------
CPU1 is handling a data transfer completion interrupt received for
the CLASS1 EP
CPU2 is handling a CLASS2 thread which is queuing data to musb for
transfer

Below is the error sequence:

         CPU1                   |             CPU2
--------------------------------------------------------------------
Data transfer completion inter- |
rupt recieved.                  |
                                |
musb INDEX reg set to CLASS1 EP |
                                |
musb LOCK is acquired.          |
                                |
                                | CLASS2 thread queues data.
                                |
                                | CLASS2 thread tries to acquire musb
                                | LOCK but lock is already taken by
                                | CLASS1, so CLASS2 thread is
                                | spinning.
                                |
From Interrupt Context musb     |
giveback function is called     |
                                |
The giveback function releases  | CLASS2 thread now acquires LOCK
LOCK                            |
                                |
ClASS1 Request's completion cal-| ClASS2 schedules the data transfer and
lback is called                 | sets the MUSB INDEX to Class2 EP number
                                |
Interrupt handler for CLASS1 EP |
tries to acquire LOCK and is    |
spinning                        |
                                |
Interrupt for Class1 EP acquires| Class2 completes the scheduling etc and
the MUSB LOCK                   | releases the musb LOCK
                                |
Interrupt for Class1 EP schedul-|
es the next data transfer       |
but musb INDEX register is still|
set to CLASS2 EP                |

Since the MUSB INDEX register is set to a different endpoint, we
read and modify the wrong registers. Hence data transfer will not
happen properly. This results in unpredictable behavior

So, the MUSB INDEX register is set to proper value again when
interrupt re-acquires the lock

Signed-off-by: Supriya Karanth <supriya.karanth@stericsson.com>
Signed-off-by: Praveena Nadahally <praveen.nadahally@stericsson.com>
Reviewed-by: srinidhi kasagar <srinidhi.kasagar@stericsson.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
usb: gadgetfs: return number of bytes on ep0 read request

commit 85b4b3c8c189e0159101f7628a71411af072ff69 upstream.

A read from GadgetFS endpoint 0 during the data stage of a control
request would always return 0 on success (as returned by
wait_event_interruptible) despite having written data into the user
buffer.
This patch makes it correctly set the return value to the number of
bytes read.

Signed-off-by: Thomas Faber <thfabba@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB: gadget: Make g_hid device class conform to spec.

commit 33d2832ab0149a26418d360af3c444969a63fb28 upstream.

HID devices should specify this in their interface descriptors, not in the
device descriptor. This fixes a "missing hardware id" bug under Windows 7 with
a VIA VL800 (3.0) controller.

Signed-off-by: Orjan Friberg <of@flatfrog.com>
Cc: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
futex: Cover all PI opcodes with cmpxchg enabled check

commit 59263b513c11398cd66a52d4c5b2b118ce1e0359 upstream.

Some of the newer futex PI opcodes do not check the cmpxchg enabled
variable and call unconditionally into the handling functions. Cover
all PI opcodes in a separate check.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
sysfs: Fix memory leak in sysfs_sd_setsecdata().

commit 93518dd2ebafcc761a8637b2877008cfd748c202 upstream.

This patch fixies follwing two memory leak patterns that reported by kmemleak.
sysfs_sd_setsecdata() is called during sys_lsetxattr() operation.
It checks sd->s_iattr is NULL or not. Then if it is NULL, it calls
sysfs_init_inode_attrs() to allocate memory.
That code is this.

iattrs = sd->s_iattr;
if (!iattrs)
                iattrs = sysfs_init_inode_attrs(sd);

The iattrs recieves sysfs_init_inode_attrs()'s result,  but sd->s_iattr
doesn't know the address. so it needs to set correct address to
sd->s_iattr to free memory in other function.

unreferenced object 0xffff880250b73e60 (size 32):
  comm "systemd", pid 1, jiffies 4294683888 (age 94.553s)
  hex dump (first 32 bytes):
    73 79 73 74 65 6d 5f 75 3a 6f 62 6a 65 63 74 5f  system_u:object_
    72 3a 73 79 73 66 73 5f 74 3a 73 30 00 00 00 00  r:sysfs_t:s0....
  backtrace:
    [<ffffffff814cb1d0>] kmemleak_alloc+0x73/0x98
    [<ffffffff811270ab>] __kmalloc+0x100/0x12c
    [<ffffffff8120775a>] context_struct_to_string+0x106/0x210
    [<ffffffff81207cc1>] security_sid_to_context_core+0x10b/0x129
    [<ffffffff812090ef>] security_sid_to_context+0x10/0x12
    [<ffffffff811fb0da>] selinux_inode_getsecurity+0x7d/0xa8
    [<ffffffff811fb127>] selinux_inode_getsecctx+0x22/0x2e
    [<ffffffff811f4d62>] security_inode_getsecctx+0x16/0x18
    [<ffffffff81191dad>] sysfs_setxattr+0x96/0x117
    [<ffffffff811542f0>] __vfs_setxattr_noperm+0x73/0xd9
    [<ffffffff811543d9>] vfs_setxattr+0x83/0xa1
    [<ffffffff811544c6>] setxattr+0xcf/0x101
    [<ffffffff81154745>] sys_lsetxattr+0x6a/0x8f
    [<ffffffff814efda9>] system_call_fastpath+0x16/0x1b
    [<ffffffffffffffff>] 0xffffffffffffffff
unreferenced object 0xffff88024163c5a0 (size 96):
  comm "systemd", pid 1, jiffies 4294683888 (age 94.553s)
  hex dump (first 32 bytes):
    00 00 00 00 ed 41 00 00 00 00 00 00 00 00 00 00  .....A..........
    00 00 00 00 00 00 00 00 0c 64 42 4f 00 00 00 00  .........dBO....
  backtrace:
    [<ffffffff814cb1d0>] kmemleak_alloc+0x73/0x98
    [<ffffffff81127402>] kmem_cache_alloc_trace+0xc4/0xee
    [<ffffffff81191cbe>] sysfs_init_inode_attrs+0x2a/0x83
    [<ffffffff81191dd6>] sysfs_setxattr+0xbf/0x117
    [<ffffffff811542f0>] __vfs_setxattr_noperm+0x73/0xd9
    [<ffffffff811543d9>] vfs_setxattr+0x83/0xa1
    [<ffffffff811544c6>] setxattr+0xcf/0x101
    [<ffffffff81154745>] sys_lsetxattr+0x6a/0x8f
    [<ffffffff814efda9>] system_call_fastpath+0x16/0x1b
    [<ffffffffffffffff>] 0xffffffffffffffff
`

Signed-off-by: Masami Ichikawa <masami256@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
TTY: Wrong unicode value copied in con_set_unimap()

commit 4a4c61b7ce26bfc9d49ea4bd121d52114bad9f99 upstream.

Bugzilla 40012: PIO_UNIMAP bug: error updating Unicode-to-font map
https://bugzilla.kernel.org/show_bug.cgi?id=40012

The unicode font map for the virtual console is a 32x32x64 table which
allocates rows dynamically as entries are added.  The unicode value
increases sequentially and should count all entries even in empty
rows.  The defect is when copying the unicode font map in con_set_unimap(),
the unicode value is not incremented properly.  The wrong unicode value
is entered in the new font map.

Signed-off-by: Liz Clark <liz.clark@hp.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
USB: serial: fix console error reporting

commit 548dd4b6da8a8e428453d55f7fa7b8a46498d147 upstream.

Do not report errors in write path if port is used as a console as this
may trigger the same error (and error report) resulting in a loop.

Reported-by: Stephen Hemminger <shemminger@vyatta.com>
Signed-off-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: fsl_udc_core: Fix scheduling while atomic dump message

commit c5cc5ed86667d4ae74fe40ee4ed893f4b46aba05 upstream.

When loading g_ether gadget, there is below message:

Backtrace:
[<80012248>] (dump_backtrace+0x0/0x10c) from [<803cb42c>] (dump_stack+0x18/0x1c)
r7:00000000 r6:80512000 r5:8052bef8 r4:80513f30
[<803cb414>] (dump_stack+0x0/0x1c) from [<8000feb4>] (show_regs+0x44/0x50)
[<8000fe70>] (show_regs+0x0/0x50) from [<8004c840>] (__schedule_bug+0x68/0x84)
r5:8052bef8 r4:80513f30
[<8004c7d8>] (__schedule_bug+0x0/0x84) from [<803cd0e4>] (__schedule+0x4b0/0x528)
r5:8052bef8 r4:809aad00
[<803ccc34>] (__schedule+0x0/0x528) from [<803cd214>] (_cond_resched+0x44/0x58)
[<803cd1d0>] (_cond_resched+0x0/0x58) from [<800a9488>] (dma_pool_alloc+0x184/0x250)
 r5:9f9b4000 r4:9fb4fb80
 [<800a9304>] (dma_pool_alloc+0x0/0x250) from [<802a8ad8>] (fsl_req_to_dtd+0xac/0x180)
[<802a8a2c>] (fsl_req_to_dtd+0x0/0x180) from [<802a8ce4>] (fsl_ep_queue+0x138/0x274)
[<802a8bac>] (fsl_ep_queue+0x0/0x274) from [<7f004328>] (composite_setup+0x2d4/0xfac [g_ether])
[<7f004054>] (composite_setup+0x0/0xfac [g_ether]) from [<802a9bb4>] (fsl_udc_irq+0x8dc/0xd38)
[<802a92d8>] (fsl_udc_irq+0x0/0xd38) from [<800704f8>] (handle_irq_event_percpu+0x54/0x188)
[<800704a4>] (handle_irq_event_percpu+0x0/0x188) from [<80070674>] (handle_irq_event+0x48/0x68)
[<8007062c>] (handle_irq_event+0x0/0x68) from [<800738ec>] (handle_level_irq+0xb4/0x138)
 r5:80514f94 r4:80514f40
 [<80073838>] (handle_level_irq+0x0/0x138) from [<8006ffa4>] (generic_handle_irq+0x38/0x44)
 r7:00000012 r6:80510b1c r5:80529860 r4:80512000
 [<8006ff6c>] (generic_handle_irq+0x0/0x44) from [<8000f4c4>] (handle_IRQ+0x54/0xb4)
[<8000f470>] (handle_IRQ+0x0/0xb4) from [<800085b8>] (tzic_handle_irq+0x64/0x94)
 r9:412fc085 r8:00000000 r7:80513f30 r6:00000001 r5:00000000
 r4:00000000
 [<80008554>] (tzic_handle_irq+0x0/0x94) from [<8000e680>] (__irq_svc+0x40/0x60)

The reason of above dump message is calling dma_poll_alloc with can-schedule
mem_flags at atomic context.

To fix this problem, below changes are made:
- fsl_req_to_dtd doesn't need to be protected by spin_lock_irqsave,
as struct usb_request can be access at process context. Move lock
to beginning of hardware visit (fsl_queue_td).
- Change the memory flag which using to allocate dTD descriptor buffer,
the memory flag can be from gadget layer.

It is tested at i.mx51 bbg board with g_mass_storage, g_ether, g_serial.

Signed-off-by: Peter Chen <peter.chen@freescale.com>
Acked-by: Li Yang <leoli@freescale.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
usb: Fix build error due to dma_mask is not at pdev_archdata at ARM

commit e90fc3cb087ce5c5f81e814358222cd6d197b5db upstream.

When build i.mx platform with imx_v6_v7_defconfig, and after adding
USB Gadget support, it has below build error:

CC      drivers/usb/host/fsl-mph-dr-of.o
drivers/usb/host/fsl-mph-dr-of.c: In function 'fsl_usb2_device_register':
drivers/usb/host/fsl-mph-dr-of.c:97: error: 'struct pdev_archdata'
has no member named 'dma_mask'

It has discussed at: http://www.spinics.net/lists/linux-usb/msg57302.html

For PowerPC, there is dma_mask at struct pdev_archdata, but there is
no dma_mask at struct pdev_archdata for ARM. The pdev_archdata is
related to specific platform, it should NOT be accessed by
cross platform drivers, like USB.

The code for pdev_archdata should be useless, as for PowerPC,
it has already gotten the value for pdev->dev.dma_mask at function
arch_setup_pdev_archdata of arch/powerpc/kernel/setup-common.c.

Tested-by: Ramneek Mehresh <ramneek.mehresh@freescale.com>
Signed-off-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
math: Introduce div64_long

commit f910381a55cdaa097030291f272f6e6e4380c39a upstream.

Add a div64_long macro which is used to devide a 64bit number by a long (which
can be 4 bytes on 32bit systems and 8 bytes on 64bit systems).

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Cc: johnstul@us.ibm.com
Link: http://lkml.kernel.org/r/1331829374-31543-1-git-send-email-levinsasha928@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
ntp: Fix integer overflow when setting time

commit a078c6d0e6288fad6d83fb6d5edd91ddb7b6ab33 upstream.

'long secs' is passed as divisor to div_s64, which accepts a 32bit
divisor. On 64bit machines that value is trimmed back from 8 bytes
back to 4, causing a divide by zero when the number is bigger than
(1 << 32) - 1 and all 32 lower bits are 0.

Use div64_long() instead.

Signed-off-by: Sasha Levin <levinsasha928@gmail.com>
Cc: johnstul@us.ibm.com
Link: http://lkml.kernel.org/r/1331829374-31543-2-git-send-email-levinsasha928@gmail.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
genirq: Fix long-term regression in genirq irq_set_irq_type() handling

commit a09b659cd68c10ec6a30cb91ebd2c327fcd5bfe5 upstream.

In 2008, commit 0c5d1eb77a8be ("genirq: record trigger type") modified the
way set_irq_type() handles the 'no trigger' condition.  However, this has
an adverse effect on PCMCIA support on Intel StrongARM and probably PXA
platforms.

PCMCIA has several status signals on the socket which can trigger
interrupts; some of these status signals depend on the card's mode
(whether it is configured in memory or IO mode).  For example, cards have
a 'Ready/IRQ' signal: in memory mode, this provides an indication to
PCMCIA that the card has finished its power up initialization.  In IO
mode, it provides the device interrupt signal.  Other status signals
switch between on-board battery status and loud speaker output.

In classical PCMCIA implementations, where you have a specific socket
controller, the controller provides a method to mask interrupts from the
socket, and importantly ignore any state transitions on the pins which
correspond with interrupts once masked.  This masking prevents unwanted
events caused by the removal and application of socket power being
forwarded.

However, on platforms where there is no socket controller, the PCMCIA
status and interrupt signals are routed to standard edge-triggered GPIOs.
These GPIOs can be configured to interrupt on rising edge, falling edge,
or never.  This is where the problems start.

Edge triggered interrupts are required to record events while disabled via
the usual methods of {free,request,disable,enable}_irq() to prevent
problems with dropped interrupts (eg, the 8390 driver uses disable_irq()
to defer the delivery of interrupts).  As a result, these interfaces can
not be used to implement the desired behaviour.

The side effect of this is that if the 'Ready/IRQ' GPIO is disabled via
disable_irq() on suspend, and enabled via enable_irq() after resume, we
will record the state transitions caused by powering events as valid
interrupts, and foward them to the card driver, which may attempt to
access a card which is not powered up.

This leads delays resume while drivers spin in their interrupt handlers,
and complaints from drivers before they realize what's happened.

Moreover, in the case of the 'Ready/IRQ' signal, this is requested and
freed by the card driver itself; the PCMCIA core has no idea whether the
interrupt is requested, and, therefore, whether a call to disable_irq()
would be valid.  (We tried this around 2.4.17 / 2.5.1 kernel era, and
ended up throwing it out because of this problem.)

Therefore, it was decided back in around 2002 to disable the edge
triggering instead, resulting in all state transitions on the GPIO being
ignored.  That's what we actually need the hardware to do.

The commit above changes this behaviour; it explicitly prevents the 'no
trigger' state being selected.

The reason that request_irq() does not accept the 'no trigger' state is
for compatibility with existing drivers which do not provide their desired
triggering configuration.  The set_irq_type() function is 'new' and not
used by non-trigger aware drivers.

Therefore, revert this change, and restore previously working platforms
back to their former state.

Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
Cc: linux@arm.linux.org.uk
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
genirq: Fix incorrect check for forced IRQ thread handler

commit 540b60e24f3f4781d80e47122f0c4486a03375b8 upstream.

We do not want a bitwise AND between boolean operands

Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Link: http://lkml.kernel.org/r/20120309135912.GA2114@dhcp-26-207.brq.redhat.com
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
rtc: Disable the alarm in the hardware (v2)

commit 41c7f7424259ff11009449f87c95656f69f9b186 upstream.

Currently, the RTC code does not disable the alarm in the hardware.

This means that after a sequence such as the one below (the files are in the
RTC sysfs), the box will boot up after 2 minutes even though we've
asked for the alarm to be turned off.

	# echo $((`cat since_epoch`)+120) > wakealarm
	# echo 0 > wakealarm
	# poweroff

Fix this by disabling the alarm when there are no timers to run.

The original version of this patch was reverted. This version
disables the irq directly instead of setting a disabled timer
in the future.

Cc: John Stultz <john.stultz@linaro.org>
Signed-off-by: Rabin Vincent <rabin.vincent@stericsson.com>
[Merged in the second revision from Rabin]
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
mm: thp: fix pmd_bad() triggering in code paths holding mmap_sem read mode

commit 1a5a9906d4e8d1976b701f889d8f35d54b928f25 upstream.

In some cases it may happen that pmd_none_or_clear_bad() is called with
the mmap_sem hold in read mode.  In those cases the huge page faults can
allocate hugepmds under pmd_none_or_clear_bad() and that can trigger a
false positive from pmd_bad() that will not like to see a pmd
materializing as trans huge.

It's not khugepaged causing the problem, khugepaged holds the mmap_sem
in write mode (and all those sites must hold the mmap_sem in read mode
to prevent pagetables to go away from under them, during code review it
seems vm86 mode on 32bit kernels requires that too unless it's
restricted to 1 thread per process or UP builds).  The race is only with
the huge pagefaults that can convert a pmd_none() into a
pmd_trans_huge().

Effectively all these pmd_none_or_clear_bad() sites running with
mmap_sem in read mode are somewhat speculative with the page faults, and
the result is always undefined when they run simultaneously.  This is
probably why it wasn't common to run into this.  For example if the
madvise(MADV_DONTNEED) runs zap_page_range() shortly before the page
fault, the hugepage will not be zapped, if the page fault runs first it
will be zapped.

Altering pmd_bad() not to error out if it finds hugepmds won't be enough
to fix this, because zap_pmd_range would then proceed to call
zap_pte_range (which would be incorrect if the pmd become a
pmd_trans_huge()).

The simplest way to fix this is to read the pmd in the local stack
(regardless of what we read, no need of actual CPU barriers, only
compiler barrier needed), and be sure it is not changing under the code
that computes its value.  Even if the real pmd is changing under the
value we hold on the stack, we don't care.  If we actually end up in
zap_pte_range it means the pmd was not none already and it was not huge,
and it can't become huge from under us (khugepaged locking explained
above).

All we need is to enforce that there is no way anymore that in a code
path like below, pmd_trans_huge can be false, but pmd_none_or_clear_bad
can run into a hugepmd.  The overhead of a barrier() is just a compiler
tweak and should not be measurable (I only added it for THP builds).  I
don't exclude different compiler versions may have prevented the race
too by caching the value of *pmd on the stack (that hasn't been
verified, but it wouldn't be impossible considering
pmd_none_or_clear_bad, pmd_bad, pmd_trans_huge, pmd_none are all inlines
and there's no external function called in between pmd_trans_huge and
pmd_none_or_clear_bad).

		if (pmd_trans_huge(*pmd)) {
			if (next-addr != HPAGE_PMD_SIZE) {
				VM_BUG_ON(!rwsem_is_locked(&tlb->mm->mmap_sem));
				split_huge_page_pmd(vma->vm_mm, pmd);
			} else if (zap_huge_pmd(tlb, vma, pmd, addr))
				continue;
			/* fall through */
		}
		if (pmd_none_or_clear_bad(pmd))

Because this race condition could be exercised without special
privileges this was reported in CVE-2012-1179.

The race was identified and fully explained by Ulrich who debugged it.
I'm quoting his accurate explanation below, for reference.

====== start quote =======
      mapcount 0 page_mapcount 1
      kernel BUG at mm/huge_memory.c:1384!

    At some point prior to the panic, a "bad pmd ..." message similar to the
    following is logged on the console:

      mm/memory.c:145: bad pmd ffff8800376e1f98(80000000314000e7).

    The "bad pmd ..." message is logged by pmd_clear_bad() before it clears
    the page's PMD table entry.

        143 void pmd_clear_bad(pmd_t *pmd)
        144 {
    ->  145         pmd_ERROR(*pmd);
        146         pmd_clear(pmd);
        147 }

    After the PMD table entry has been cleared, there is an inconsistency
    between the actual number of PMD table entries that are mapping the page
    and the page's map count (_mapcount field in struct page). When the page
    is subsequently reclaimed, __split_huge_page() detects this inconsistency.

       1381         if (mapcount != page_mapcount(page))
       1382                 printk(KERN_ERR "mapcount %d page_mapcount %d\n",
       1383                        mapcount, page_mapcount(page));
    -> 1384         BUG_ON(mapcount != page_mapcount(page));

    The root cause of the problem is a race of two threads in a multithreaded
    process. Thread B incurs a page fault on a virtual address that has never
    been accessed (PMD entry is zero) while Thread A is executing an madvise()
    system call on a virtual address within the same 2 MB (huge page) range.

               virtual address space
              .---------------------.
              |                     |
              |                     |
            .-|---------------------|
            | |                     |
            | |                     |<-- B(fault)
            | |                     |
      2 MB  | |/////////////////////|-.
      huge <  |/////////////////////|  > A(range)
      page  | |/////////////////////|-'
            | |                     |
            | |                     |
            '-|---------------------|
              |                     |
              |                     |
              '---------------------'

    - Thread A is executing an madvise(..., MADV_DONTNEED) system call
      on the virtual address range "A(range)" shown in the picture.

    sys_madvise
      // Acquire the semaphore in shared mode.
      down_read(&current->mm->mmap_sem)
      ...
      madvise_vma
        switch (behavior)
        case MADV_DONTNEED:
             madvise_dontneed
               zap_page_range
                 unmap_vmas
                   unmap_page_range
                     zap_pud_range
                       zap_pmd_range
                         //
                         // Assume that this huge page has never been accessed.
                         // I.e. content of the PMD entry is zero (not mapped).
                         //
                         if (pmd_trans_huge(*pmd)) {
                             // We don't get here due to the above assumption.
                         }
                         //
                         // Assume that Thread B incurred a page fault and
             .---------> // sneaks in here as shown below.
             |           //
             |           if (pmd_none_or_clear_bad(pmd))
             |               {
             |                 if (unlikely(pmd_bad(*pmd)))
             |                     pmd_clear_bad
             |                     {
             |                       pmd_ERROR
             |                         // Log "bad pmd ..." message here.
             |                       pmd_clear
             |                         // Clear the page's PMD entry.
             |                         // Thread B incremented the map count
             |                         // in page_add_new_anon_rmap(), but
             |                         // now the page is no longer mapped
             |                         // by a PMD entry (-> inconsistency).
             |                     }
             |               }
             |
             v
    - Thread B is handling a page fault on virtual address "B(fault)" shown
      in the picture.

    ...
    do_page_fault
      __do_page_fault
        // Acquire the semaphore in shared mode.
        down_read_trylock(&mm->mmap_sem)
        ...
        handle_mm_fault
          if (pmd_none(*pmd) && transparent_hugepage_enabled(vma))
              // We get here due to the above assumption (PMD entry is zero).
              do_huge_pmd_anonymous_page
                alloc_hugepage_vma
                  // Allocate a new transparent huge page here.
                ...
                __do_huge_pmd_anonymous_page
                  ...
                  spin_lock(&mm->page_table_lock)
                  ...
                  page_add_new_anon_rmap
                    // Here we increment the page's map count (starts at -1).
                    atomic_set(&page->_mapcount, 0)
                  set_pmd_at
                    // Here we set the page's PMD entry which will be cleared
                    // when Thread A calls pmd_clear_bad().
                  ...
                  spin_unlock(&mm->page_table_lock)

    The mmap_sem does not prevent the race because both threads are acquiring
    it in shared mode (down_read).  Thread B holds the page_table_lock while
    the page's map count and PMD table entry are updated.  However, Thread A
    does not synchronize on that lock.

====== end quote =======

[akpm@linux-foundation.org: checkpatch fixes]
Reported-by: Ulrich Obergfell <uobergfe@redhat.com>
Signed-off-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Hugh Dickins <hughd@google.com>
Cc: Dave Jones <davej@redhat.com>
Acked-by: Larry Woodman <lwoodman@redhat.com>
Acked-by: Rik van Riel <riel@redhat.com>
Cc: Mark Salter <msalter@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Conflicts:
	arch/x86/kernel/vm86_32.c
bootmem/sparsemem: remove limit constraint in alloc_bootmem_section

commit f5bf18fa22f8c41a13eb8762c7373eb3a93a7333 upstream.

While testing AMS (Active Memory Sharing) / CMO (Cooperative Memory
Overcommit) on powerpc, we tripped the following:

  kernel BUG at mm/bootmem.c:483!
  cpu 0x0: Vector: 700 (Program Check) at [c000000000c03940]
      pc: c000000000a62bd8: .alloc_bootmem_core+0x90/0x39c
      lr: c000000000a64bcc: .sparse_early_usemaps_alloc_node+0x84/0x29c
      sp: c000000000c03bc0
     msr: 8000000000021032
    current = 0xc000000000b0cce0
    paca    = 0xc000000001d80000
      pid   = 0, comm = swapper
  kernel BUG at mm/bootmem.c:483!
  enter ? for help
  [c000000000c03c80] c000000000a64bcc
  .sparse_early_usemaps_alloc_node+0x84/0x29c
  [c000000000c03d50] c000000000a64f10 .sparse_init+0x12c/0x28c
  [c000000000c03e20] c000000000a474f4 .setup_arch+0x20c/0x294
  [c000000000c03ee0] c000000000a4079c .start_kernel+0xb4/0x460
  [c000000000c03f90] c000000000009670 .start_here_common+0x1c/0x2c

This is

        BUG_ON(limit && goal + size > limit);

and after some debugging, it seems that

	goal = 0x7ffff000000
	limit = 0x80000000000

and sparse_early_usemaps_alloc_node ->
sparse_early_usemaps_alloc_pgdat_section calls

	return alloc_bootmem_section(usemap_size() * count, section_nr);

This is on a system with 8TB available via the AMS pool, and as a quirk
of AMS in firmware, all of that memory shows up in node 0.  So, we end
up with an allocation that will fail the goal/limit constraints.

In theory, we could "fall-back" to alloc_bootmem_node() in
sparse_early_usemaps_alloc_node(), but since we actually have HOTREMOVE
defined, we'll BUG_ON() instead.  A simple solution appears to be to
unconditionally remove the limit condition in alloc_bootmem_section,
meaning allocations are allowed to cross section boundaries (necessary
for systems of this size).

Johannes Weiner pointed out that if alloc_bootmem_section() no longer
guarantees section-locality, we need check_usemap_section_nr() to print
possible cross-dependencies between node descriptors and the usemaps
allocated through it.  That makes the two loops in
sparse_early_usemaps_alloc_node() identical, so re-factor the code a
bit.

[akpm@linux-foundation.org: code simplification]
Signed-off-by: Nishanth Aravamudan <nacc@us.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Anton Blanchard <anton@au1.ibm.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Ben Herrenschmidt <benh@kernel.crashing.org>
Cc: Robert Jennings <rcj@linux.vnet.ibm.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
hugetlbfs: avoid taking i_mutex from hugetlbfs_read()

commit a05b0855fd15504972dba2358e5faa172a1e50ba upstream.

Taking i_mutex in hugetlbfs_read() can result in deadlock with mmap as
explained below

 Thread A:
  read() on hugetlbfs
   hugetlbfs_read() called
    i_mutex grabbed
     hugetlbfs_read_actor() called
      __copy_to_user() called
       page fault is triggered
 Thread B, sharing address space with A:
  mmap() the same file
   ->mmap_sem is grabbed on task_B->mm->mmap_sem
    hugetlbfs_file_mmap() is called
     attempt to grab ->i_mutex and block waiting for A to give it up
 Thread A:
  pagefault handled blocked on attempt to grab task_A->mm->mmap_sem,
 which happens to be the same thing as task_B->mm->mmap_sem.  Block waiting
 for B to give it up.

AFAIU the i_mutex locking was added to hugetlbfs_read() as per
http://lkml.indiana.edu/hypermail/linux/kernel/0707.2/3066.html to take
care of the race between truncate and read.  This patch fixes this by
looking at page->mapping under lock_page() (find_lock_page()) to ensure
that the inode didn't get truncated in the range during a parallel read.

Ideally we can extend the patch to make sure we don't increase i_size in
mmap.  But that will break userspace, because applications will now have
to use truncate(2) to increase i_size in hugetlbfs.

Based on the original patch from Hillf Danton.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Cc: Hillf Danton <dhillf@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tcm_loop: Set residual field for SCSI commands

commit 6cf3fa6918baab0c447f1206f1cef9166ad04864 upstream.

If the target core signals an over- or under-run, tcm_loop should call
scsi_set_resid() to tell the SCSI midlayer about the residual data length.

The difference can be seen by doing something like

    strace -eioctl sg_raw -r 1024 /dev/sda 8 0 0 0 1 0 > /dev/null

and looking at the "resid=" part of the SG_IO ioctl -- after this patch,
the field is correctly reported as 512.

Signed-off-by: Roland Dreier <roland@purestorage.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
udlfb: remove sysfs framebuffer device with USB .disconnect()

commit ce880cb860f36694d2cdebfac9e6ae18176fe4c4 upstream.

The USB graphics card driver delays the unregistering of the framebuffer
device to a workqueue, which breaks the userspace visible remove uevent
sequence. Recent userspace tools started to support USB graphics card
hotplug out-of-the-box and rely on proper events sent by the kernel.

The framebuffer device is a direct child of the USB interface which is
removed immediately after the USB .disconnect() callback. But the fb device
in /sys stays around until its final cleanup, at a time where all the parent
devices have been removed already.

To work around that, we remove the sysfs fb device directly in the USB
.disconnect() callback and leave only the cleanup of the internal fb
data to the delayed work.

Before:
 add      /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2 (usb)
 add      /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0 (usb)
 add      /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/graphics/fb0 (graphics)
 remove   /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0 (usb)
 remove   /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2 (usb)
 remove   /2-1.2:1.0/graphics/fb0 (graphics)

After:
 add      /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2 (usb)
 add      /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0 (usb)
 add      /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/graphics/fb1 (graphics)
 remove   /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0/graphics/fb1 (graphics)
 remove   /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2/2-1.2:1.0 (usb)
 remove   /devices/pci0000:00/0000:00:1d.0/usb2/2-1/2-1.2 (usb)

Tested-by: Bernie Thompson <bernie@plugable.com>
Acked-by: Bernie Thompson <bernie@plugable.com>
Signed-off-by: Kay Sievers <kay.sievers@vrfy.org>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
tcm_fc: Fix fc_exch memory leak in ft_send_resp_status

commit 031ed4d565b31880a4136bb7366bc89f5b1dba7d upstream.

This patch fixes a bug in tcm_fc where fc_exch memory from fc_exch_mgr->ep_pool
is currently being leaked by ft_send_resp_status() usage.  Following current
code in ft_queue_status() response path, using lport->tt.seq_send() needs to be
followed by a lport->tt.exch_done() in order to release fc_exch memory back into
libfc_em kmem_cache.

ft_send_resp_status() code is currently used in pre submit se_cmd ft_send_work()
error exceptions, TM request setup exceptions, and main TM response callback
path in ft_queue_tm_resp().  This bugfix addresses the leak in these cases.

Cc: Mark D Rustad <mark.d.rustad@intel.com>
Cc: Kiran Patil <kiran.patil@intel.com>
Cc: Robert Love <robert.w.love@intel.com>
Cc: Andy Grover <agrover@redhat.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>