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  1. 25 5月, 2011 9 次提交
  3. 19 5月, 2011 1 次提交
    • G
      drivercore: revert addition of of_match to struct device · b1608d69
      由 Grant Likely 提交于 
      Commit b826291c, "drivercore/dt: add a match table pointer to struct
device" added an of_match pointer to struct device to cache the
of_match_table entry discovered at driver match time.  This was unsafe
because matching is not an atomic operation with probing a driver.  If
two or more drivers are attempted to be matched to a driver at the
same time, then the cached matching entry pointer could get
overwritten.

This patch reverts the of_match cache pointer and reworks all users to
call of_match_device() directly instead.
Signed-off-by: NGrant Likely <grant.likely@secretlab.ca>
      b1608d69
  5. 18 5月, 2011 2 次提交
  7. 17 5月, 2011 4 次提交
    • J
      scsi: remove performance regression due to async queue run · 9937a5e2
      由 Jens Axboe 提交于 
      Commit c21e6beb removed our queue request_fn re-enter
protection, and defaulted to always running the queues from
kblockd to be safe. This was a known potential slow down,
but should be safe.

Unfortunately this is causing big performance regressions for
some, so we need to improve this logic. Looking into the details
of the re-enter, the real issue is on requeue of requests.

Requeue of requests upon seeing a BUSY condition from the device
ends up re-running the queue, causing traces like this:

scsi_request_fn()
        scsi_dispatch_cmd()
                scsi_queue_insert()
                        __scsi_queue_insert()
                                scsi_run_queue()
					scsi_request_fn()
						...

potentially causing the issue we want to avoid. So special
case the requeue re-run of the queue, but improve it to offload
the entire run of local queue and starved queue from a single
workqueue callback. This is a lot better than potentially
kicking off a workqueue run for each device seen.

This also fixes the issue of the local device going into recursion,
since the above mentioned commit never moved that queue run out
of line.
Signed-off-by: NJens Axboe <jaxboe@fusionio.com>
      9937a5e2
    • Y
      PCI: Clear bridge resource flags if requested size is 0 · 93d2175d
      由 Yinghai Lu 提交于 
      During pci remove/rescan testing found:

  pci 0000:c0:03.0: PCI bridge to [bus c4-c9]
  pci 0000:c0:03.0:   bridge window [io  0x1000-0x0fff]
  pci 0000:c0:03.0:   bridge window [mem 0xf0000000-0xf00fffff]
  pci 0000:c0:03.0:   bridge window [mem 0xfc180000000-0xfc197ffffff 64bit pref]
  pci 0000:c0:03.0: device not available (can't reserve [io  0x1000-0x0fff])
  pci 0000:c0:03.0: Error enabling bridge (-22), continuing
  pci 0000:c0:03.0: enabling bus mastering
  pci 0000:c0:03.0: setting latency timer to 64
  pcieport 0000:c0:03.0: device not available (can't reserve [io  0x1000-0x0fff])
  pcieport: probe of 0000:c0:03.0 failed with error -22

This bug was caused by commit c8adf9a3 ("PCI: pre-allocate
additional resources to devices only after successful allocation of
essential resources.")

After that commit, pci_hotplug_io_size is changed to additional_io_size
from minium size.  So it will not go through resource_size(res) != 0
path, and will not be reset.

The root cause is: pci_bridge_check_ranges will set RESOURCE_IO flag for
pci bridge, and later if children do not need IO resource.  those bridge
resources will not need to be allocated.  but flags is still there.
that will confuse the the pci_enable_bridges later.

related code:

   static void assign_requested_resources_sorted(struct resource_list *head,
                                    struct resource_list_x *fail_head)
   {
           struct resource *res;
           struct resource_list *list;
           int idx;

           for (list = head->next; list; list = list->next) {
                   res = list->res;
                   idx = res - &list->dev->resource[0];
                   if (resource_size(res) && pci_assign_resource(list->dev, idx)) {
   ...
                           reset_resource(res);
                   }
           }
   }

At last, We have to clear the flags in pbus_size_mem/io when requested
size == 0 and !add_head.  becasue this case it will not go through
adjust_resources_sorted().

Just make size1 = size0 when !add_head. it will make flags get cleared.

At the same time when requested size == 0, add_size != 0, will still
have in head and add_list.  because we do not clear the flags for it.

After this, we will get right result:

  pci 0000:c0:03.0: PCI bridge to [bus c4-c9]
  pci 0000:c0:03.0:   bridge window [io  disabled]
  pci 0000:c0:03.0:   bridge window [mem 0xf0000000-0xf00fffff]
  pci 0000:c0:03.0:   bridge window [mem 0xfc180000000-0xfc197ffffff 64bit pref]
  pci 0000:c0:03.0: enabling bus mastering
  pci 0000:c0:03.0: setting latency timer to 64
  pcieport 0000:c0:03.0: setting latency timer to 64
  pcieport 0000:c0:03.0: irq 160 for MSI/MSI-X
  pcieport 0000:c0:03.0: Signaling PME through PCIe PME interrupt
  pci 0000:c4:00.0: Signaling PME through PCIe PME interrupt
  pcie_pme 0000:c0:03.0:pcie01: service driver pcie_pme loaded
  aer 0000:c0:03.0:pcie02: service driver aer loaded
  pciehp 0000:c0:03.0:pcie04: Hotplug Controller:

v3: more simple fix. also fix one typo in pbus_size_mem
Signed-off-by: NYinghai Lu <yinghai@kernel.org>
Reviewed-by: NRam Pai <linuxram@us.ibm.com>
Cc: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      93d2175d
    • T
      vmxnet3: Fix inconsistent LRO state after initialization · ebde6f8a
      由 Thomas Jarosch 提交于 
      During initialization of vmxnet3, the state of LRO
gets out of sync with netdev->features.

This leads to very poor TCP performance in a IP forwarding
setup and is hitting many VMware users.

Simplified call sequence:
1. vmxnet3_declare_features() initializes "adapter->lro" to true.

2. The kernel automatically disables LRO if IP forwarding is enabled,
so vmxnet3_set_flags() gets called. This also updates netdev->features.

3. Now vmxnet3_setup_driver_shared() is called. "adapter->lro" is still
set to true and LRO gets enabled again, even though
netdev->features shows it's disabled.

Fix it by updating "adapter->lro", too.

The private vmxnet3 adapter flags are scheduled for removal
in net-next, see commit a0d2730c
"net: vmxnet3: convert to hw_features".

Patch applies to 2.6.37 / 2.6.38 and 2.6.39-rc6.

Please CC: comments.
Signed-off-by: NThomas Jarosch <thomas.jarosch@intra2net.com>
Acked-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      ebde6f8a
    • B
      sfc: Fix oops in register dump after mapping change · 867955f5
      由 Ben Hutchings 提交于 
      Commit 747df225 ('sfc: Always map MCDI
shared memory as uncacheable') introduced a separate mapping for the
MCDI shared memory (MC_TREG_SMEM).  This means we can no longer easily
include it in the register dump.  Since it is not particularly useful
in debugging, substitute a recognisable dummy value.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      867955f5
  9. 16 5月, 2011 4 次提交
    • C
      Revert "mmc: fix a race between card-detect rescan and clock-gate work instances" · 86f315bb
      由 Chris Ball 提交于 
      This reverts commit 26fc8775, which has
been reported to cause boot/resume-time crashes for some users:

https://bbs.archlinux.org/viewtopic.php?id=118751.
Signed-off-by: NChris Ball <cjb@laptop.org>
Cc: <stable@kernel.org>
      86f315bb
    • C
      drm: Take lock around probes for drm_fb_helper_hotplug_event · 752d2635
      由 Chris Wilson 提交于 
      We need to hold the dev->mode_config.mutex whilst detecting the output
status. But we also need to drop it for the call into
drm_fb_helper_single_fb_probe(), which indirectly acquires the lock when
attaching the fbcon.

Failure to do so exposes a race with normal output probing. Detected by
adding some warnings that the mutex is held to the backend detect routines:

[   17.772456] WARNING: at drivers/gpu/drm/i915/intel_crt.c:471 intel_crt_detect+0x3e/0x373 [i915]()
[   17.772458] Hardware name: Latitude E6400
[   17.772460] Modules linked in: ....
[   17.772582] Pid: 11, comm: kworker/0:1 Tainted: G        W 2.6.38.4-custom.2 #8
[   17.772584] Call Trace:
[   17.772591]  [<ffffffff81046af5>] ? warn_slowpath_common+0x78/0x8c
[   17.772603]  [<ffffffffa03f3e5c>] ? intel_crt_detect+0x3e/0x373 [i915]
[   17.772612]  [<ffffffffa0355d49>] ?  drm_helper_probe_single_connector_modes+0xbf/0x2af [drm_kms_helper]
[   17.772619]  [<ffffffffa03534d5>] ?  drm_fb_helper_probe_connector_modes+0x39/0x4d [drm_kms_helper]
[   17.772625]  [<ffffffffa0354760>] ?  drm_fb_helper_hotplug_event+0xa5/0xc3 [drm_kms_helper]
[   17.772633]  [<ffffffffa035577f>] ? output_poll_execute+0x146/0x17c [drm_kms_helper]
[   17.772638]  [<ffffffff81193c01>] ? cfq_init_queue+0x247/0x345
[   17.772644]  [<ffffffffa0355639>] ? output_poll_execute+0x0/0x17c [drm_kms_helper]
[   17.772648]  [<ffffffff8105b540>] ? process_one_work+0x193/0x28e
[   17.772652]  [<ffffffff8105c6bc>] ? worker_thread+0xef/0x172
[   17.772655]  [<ffffffff8105c5cd>] ? worker_thread+0x0/0x172
[   17.772658]  [<ffffffff8105c5cd>] ? worker_thread+0x0/0x172
[   17.772663]  [<ffffffff8105f767>] ? kthread+0x7a/0x82
[   17.772668]  [<ffffffff8100a724>] ? kernel_thread_helper+0x4/0x10
[   17.772671]  [<ffffffff8105f6ed>] ? kthread+0x0/0x82
[   17.772674]  [<ffffffff8100a720>] ? kernel_thread_helper+0x0/0x10
Reported-by: NFrederik Himpe <fhimpe@telenet.be>
References: https://bugs.freedesktop.org/show_bug.cgi?id=36394Signed-off-by: NChris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: NDave Airlie <airlied@redhat.com>
      752d2635
    • A
      drm/i915: Revert i915.semaphore=1 default from 47ae63e0 · 8eea1be1
      由 Andy Lutomirski 提交于 
      My Q67 / i7-2600 box has rev09 Sandy Bridge graphics.  It hangs
instantly when GNOME loads and it hangs so hard the reset button
doesn't work.  Setting i915.semaphore=0 fixes it.

Semaphores were disabled in a1656b90
in 2.6.38 and were re-enabled by

commit 47ae63e0
Merge: c59a333f 467cffba
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Mon Mar 7 12:32:44 2011 +0000

    Merge branch 'drm-intel-fixes' into drm-intel-next

    Apply the trivial conflicting regression fixes, but keep GPU semaphores
    enabled.

    Conflicts:
        drivers/gpu/drm/i915/i915_drv.h
        drivers/gpu/drm/i915/i915_gem_execbuffer.c

(It's worth noting that the offending change is i915_drv.c,
 which is not a conflict.)
Signed-off-by: NAndy Lutomirski <luto@mit.edu>
Acked-by: NKeith Packard <keithp@keithp.com>
Signed-off-by: NDave Airlie <airlied@redhat.com>
      8eea1be1
    • F
      vga_switcheroo: don't toggle-switch devices · a67b8887
      由 Florian Mickler 提交于 
      If the requested device is already active, ignore the request.

This restores the original behaviour of the interface. The change was
probably an unintended side effect of

commit 66b37c67 vga_switcheroo: split switching into two stages

which did not take into account to duplicate the !active check in the split-off
stage2.

Fix this by factoring that check out of stage1 into the debugfs_write routine.

References: https://bugzilla.kernel.org/show_bug.cgi?id=34252Reported-by: NIgor Murzov <e-mail@date.by>
Tested-by: NIgor Murzov <e-mail@date.by>
Signed-off-by: NFlorian Mickler <florian@mickler.org>
Signed-off-by: NDave Airlie <airlied@redhat.com>
      a67b8887
  11. 15 5月, 2011 4 次提交
    • T
      libata: fix oops when LPM is used with PMP · 5f6f12cc
      由 Tejun Heo 提交于 
      ae01b249 (libata: Implement ATA_FLAG_NO_DIPM and apply it to mcp65)
added ATA_FLAG_NO_DIPM and made ata_eh_set_lpm() check the flag.
However, @ap is NULL if @link points to a PMP link and thus the
unconditional @ap->flags dereference leads to the following oops.

  BUG: unable to handle kernel NULL pointer dereference at 0000000000000018
  IP: [<ffffffff813f98e1>] ata_eh_recover+0x9a1/0x1510
  ...
  Pid: 295, comm: scsi_eh_4 Tainted: P            2.6.38.5-core2 #1 System76, Inc. Serval Professional/Serval Professional
  RIP: 0010:[<ffffffff813f98e1>]  [<ffffffff813f98e1>] ata_eh_recover+0x9a1/0x1510
  RSP: 0018:ffff880132defbf0  EFLAGS: 00010246
  RAX: 0000000000000000 RBX: ffff880132f40000 RCX: 0000000000000000
  RDX: ffff88013377c000 RSI: ffff880132f40000 RDI: 0000000000000000
  RBP: ffff880132defce0 R08: ffff88013377dc58 R09: ffff880132defd98
  R10: 0000000000000000 R11: 00000000ffffffff R12: 0000000000000000
  R13: 0000000000000000 R14: ffff88013377c000 R15: 0000000000000000
  FS:  0000000000000000(0000) GS:ffff8800bf700000(0000) knlGS:0000000000000000
  CS:  0010 DS: 0000 ES: 0000 CR0: 000000008005003b
  CR2: 0000000000000018 CR3: 0000000001a03000 CR4: 00000000000406e0
  DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
  DR3: 0000000000000000 DR6: 00000000ffff0ff0 DR7: 0000000000000400
  Process scsi_eh_4 (pid: 295, threadinfo ffff880132dee000, task ffff880133b416c0)
  Stack:
   0000000000000000 ffff880132defcc0 0000000000000000 ffff880132f42738
   ffffffff813ee8f0 ffffffff813eefe0 ffff880132defd98 ffff88013377f190
   ffffffffa00b3e30 ffffffff813ef030 0000000032defc60 ffff880100000000
  Call Trace:
   [<ffffffff81400867>] sata_pmp_error_handler+0x607/0xc30
   [<ffffffffa00b273f>] ahci_error_handler+0x1f/0x70 [libahci]
   [<ffffffff813faade>] ata_scsi_error+0x5be/0x900
   [<ffffffff813cf724>] scsi_error_handler+0x124/0x650
   [<ffffffff810834b6>] kthread+0x96/0xa0
   [<ffffffff8100cd64>] kernel_thread_helper+0x4/0x10
  Code: 8b 95 70 ff ff ff b8 00 00 00 00 48 3b 9a 10 2e 00 00 48 0f 44 c2 48 89 85 70 ff ff ff 48 8b 8d 70 ff ff ff f6 83 69 02 00 00 01 <48> 8b 41 18 0f 85 48 01 00 00 48 85 c9 74 12 48 8b 51 08 48 83
  RIP  [<ffffffff813f98e1>] ata_eh_recover+0x9a1/0x1510
   RSP <ffff880132defbf0>
  CR2: 0000000000000018

Fix it by testing @link->ap->flags instead.

stable: ATA_FLAG_NO_DIPM was added during 2.6.39 cycle but was
        backported to 2.6.37 and 38.  This is a fix for that and thus
        also applicable to 2.6.37 and 38.
Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: N"Nathan A. Mourey II" <nmoureyii@ne.rr.com>
LKML-Reference: <1304555277.2059.2.camel@localhost.localdomain>
Cc: Connor H <cmdkhh@gmail.com>
Cc: stable@kernel.org
Signed-off-by: NJeff Garzik <jgarzik@pobox.com>
      5f6f12cc
    • T
      Revert "libata: ahci_start_engine compliant to AHCI spec" · 22fe9446
      由 Tejun Heo 提交于 
      This reverts commit 270dac35.

The commits causes command timeouts on AC plug/unplug.  It isn't yet
clear why.  As the commit was for a single rather obscure controller,
revert the change for now.

The problem was reported and bisected by Gu Rui in bug#34692.

 https://bugzilla.kernel.org/show_bug.cgi?id=34692

Also, reported by Rafael and Michael in the following thread.

 http://thread.gmane.org/gmane.linux.kernel/1138771Signed-off-by: NTejun Heo <tj@kernel.org>
Reported-by: NGu Rui <chaos.proton@gmail.com>
Reported-by: NRafael J. Wysocki <rjw@sisk.pl>
Reported-by: NMichael Leun <lkml20100708@newton.leun.net>
Cc: Jian Peng <jipeng2005@gmail.com>
Cc: Jeff Garzik <jgarzik@pobox.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      22fe9446
    • B
      Further fbcon sanity checking · c590cece
      由 Bruno Prémont 提交于 
      This moves the

    if (num_registered_fb == FB_MAX)
            return -ENXIO;

check _AFTER_ the call to do_remove_conflicting_framebuffers() as this
would (now in a safe way) allow a native driver to replace the
conflicting one even if all slots in registered_fb[] are taken.

This also prevents unregistering a framebuffer that is no longer
registered (vga16f will unregister at module unload time even if the
frame buffer had been unregistered earlier due to being found
conflicting).
Signed-off-by: NBruno Prémont <bonbons@linux-vserver.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      c590cece
    • L
      fbmem: fix remove_conflicting_framebuffers races · 712f3147
      由 Linus Torvalds 提交于 
      When a register_framebuffer() call results in us removing old
conflicting framebuffers, the new registration_lock doesn't protect that
situation.  And we can't just add the same locking to the function,
because these functions call each other: register_framebuffer() calls
remove_conflicting_framebuffers, which in turn calls
unregister_framebuffer for any conflicting entry.

In order to fix it, this just creates wrapper functions around all three
functions and makes the versions that actually do the work be called
"do_xxx()", leaving just the wrapper that gets the lock and calls the
worker function.

So the rule becomes simply that "do_xxxx()" has to be called with the
lock held, and now do_register_framebuffer() can just call
do_remove_conflicting_framebuffers(), and that in turn can call
_do_unregister_framebuffer(), and there is no deadlock, and we can hold
the registration lock over the whole sequence, fixing the races.

It also makes error cases simpler, and fixes one situation where we
would return from unregister_framebuffer() without releasing the lock,
pointed out by Bruno Prémont.
Tested-by: NBruno Prémont <bonbons@linux-vserver.org>
Tested-by: NAnca Emanuel <anca.emanuel@gmail.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      712f3147
  13. 14 5月, 2011 3 次提交
  15. 13 5月, 2011 9 次提交
  17. 12 5月, 2011 4 次提交
    • L
      fbmem: make read/write/ioctl use the frame buffer at open time · c47747fd
      由 Linus Torvalds 提交于 
      read/write/ioctl on a fbcon file descriptor has traditionally used the
fbcon not when it was opened, but as it was at the time of the call.
That makes no sense, but the lack of sense is much more obvious now that
we properly ref-count the usage - it means that the ref-counting doesn't
actually protect operations we do on the frame buffer.

This changes it to look at the fb_info that we got at open time, but in
order to avoid using a frame buffer long after it has been unregistered,
we do verify that it is still current, and return -ENODEV if not.
Acked-by: NTim Gardner <tim.gardner@canonical.com>
Tested-by: NDaniel J Blueman <daniel.blueman@gmail.com>
Tested-by: NAnca Emanuel <anca.emanuel@gmail.com>
Cc: Bruno Prémont <bonbons@linux-vserver.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Andy Whitcroft <andy.whitcroft@canonical.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      c47747fd
    • L
      fbcon: add lifetime refcount to opened frame buffers · 698b3682
      由 Linus Torvalds 提交于 
      This just adds the refcount and the new registration lock logic.  It
does not (for example) actually change the read/write/ioctl routines to
actually use the frame buffer that was opened: those function still end
up alway susing whatever the current frame buffer is at the time of the
call.

Without this, if something holds the frame buffer open over a
framebuffer switch, the close() operation after the switch will access a
fb_info that has been free'd by the unregistering of the old frame
buffer.

(The read/write/ioctl operations will normally not cause problems,
because they will - illogically - pick up the new fbcon instead.  But a
switch that happens just as one of those is going on might see problems
too, the window is just much smaller: one individual op rather than the
whole open-close sequence.)

This use-after-free is apparently fairly easily triggered by the Ubuntu
11.04 boot sequence.
Acked-by: NTim Gardner <tim.gardner@canonical.com>
Tested-by: NDaniel J Blueman <daniel.blueman@gmail.com>
Tested-by: NAnca Emanuel <anca.emanuel@gmail.com>
Cc: Bruno Prémont <bonbons@linux-vserver.org>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>
Cc: Paul Mundt <lethal@linux-sh.org>
Cc: Dave Airlie <airlied@redhat.com>
Cc: Andy Whitcroft <andy.whitcroft@canonical.com>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      698b3682
    • B
      sfc: Always map MCDI shared memory as uncacheable · 747df225
      由 Ben Hutchings 提交于 
      We enabled write-combining for memory-mapped registers in commit
65f0b417, but inhibited it for the
MCDI shared memory where this is not supported.  However,
write-combining mappings also allow read-reordering, which may also
be a problem.

I found that when an SFC9000-family controller is connected to an
Intel 3000 chipset, and write-combining is enabled, the controller
stops responding to PCIe read requests during driver initialisation
while the driver is polling for completion of an MCDI command.  This
results in an NMI and system hang.  Adding read memory barriers
between all reads to the shared memory area appears to reduce but not
eliminate the probability of this.

We have not yet established whether this is a bug in our BIU or in the
PCIe bridge.  For now, work around by mapping the shared memory area
separately.
Signed-off-by: NBen Hutchings <bhutchings@solarflare.com>
      747df225
    • A
      ehea: Fix memory hotplug oops · 21ccc793
      由 Anton Blanchard 提交于 
      The ehea driver oopses during memory hotplug if the ports are not
up. A simple testcase:

# ifconfig ethX down
# echo offline > /sys/devices/system/memory/memory32/state

Oops: Kernel access of bad area, sig: 11 [#1]
last sysfs file: /sys/devices/system/memory/memory32/state
REGS: c000000709393110 TRAP: 0300   Not tainted  (2.6.39-rc2-01385-g7ef73bca-dirty)
DAR: 0000000000000000, DSISR: 40000000
...
NIP [c000000000067c98] .__wake_up_common+0x48/0xf0
LR [c00000000006d034] .__wake_up+0x54/0x90
Call Trace:
[c00000000006d034] .__wake_up+0x54/0x90
[d000000006bb6270] .ehea_rereg_mrs+0x140/0x730 [ehea]
[d000000006bb69c4] .ehea_mem_notifier+0x164/0x170 [ehea]
[c0000000006fc8a8] .notifier_call_chain+0x78/0xf0
[c0000000000b3d70] .__blocking_notifier_call_chain+0x70/0xb0
[c000000000458d78] .memory_notify+0x28/0x40
[c0000000001871d8] .remove_memory+0x208/0x6d0
[c000000000458264] .memory_section_action+0x94/0x140
[c0000000004583ec] .memory_block_change_state+0xdc/0x1d0
[c0000000004585cc] .store_mem_state+0xec/0x160
[c00000000044768c] .sysdev_store+0x3c/0x50
[c00000000020b48c] .sysfs_write_file+0xec/0x1f0
[c00000000018f86c] .vfs_write+0xec/0x1e0
[c00000000018fa88] .SyS_write+0x58/0xd0

To fix this, initialise the waitqueues during port probe instead
of port open.
Signed-off-by: NAnton Blanchard <anton@samba.org>
Cc: stable@kernel.org
Acked-by: NBreno Leitao <leitao@linux.vnet.ibm.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>
      21ccc793