A number of problems can occur due to races between
resync/recovery and discard.

- if sync_request calls handle_stripe() while a discard is
  happening on the stripe, it might call handle_stripe_clean_event
  before all of the individual discard requests have completed
  (so some devices are still locked, but not all).
  Since commit ca64cae9
     md/raid5: Make sure we clear R5_Discard when discard is finished.
  this will cause R5_Discard to be cleared for the parity device,
  so handle_stripe_clean_event() will not be called when the other
  devices do become unlocked, so their ->written will not be cleared.
  This ultimately leads to a WARN_ON in init_stripe and a lock-up.

- If handle_stripe_clean_event() does clear R5_UPTODATE at an awkward
  time for resync, it can lead to s->uptodate being less than disks
  in handle_parity_checks5(), which triggers a BUG (because it is
  one).

So:
 - keep R5_Discard on the parity device until all other devices have
   completed their discard request
 - make sure we don't try to have a 'discard' and a 'sync' action at
   the same time.
   This involves a new stripe flag to we know when a 'discard' is
   happening, and the use of R5_Overlap on the parity disk so when a
   discard is wanted while a sync is active, so we know to wake up
   the discard at the appropriate time.

Discard support for RAID5 was added in 3.7, so this is suitable for
any -stable kernel since 3.7.

Cc: stable@vger.kernel.org (v3.7+)
Reported-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Tested-by: Jes Sorensen <Jes.Sorensen@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

MD: Prevent sysfs operations on uninitialized kobjects

Device-mapper does not use sysfs; but when device-mapper is leveraging
MD's RAID personalities, MD sometimes attempts to update sysfs.  This
patch adds checks for 'mddev-kobj.sd' in sysfs_[un]link_rdev to ensure
it is about to operate on something valid.  This patch also checks for
'mddev->kobj.sd' before calling 'sysfs_notify' in 'remove_and_add_spares'.
Although 'sysfs_notify' already makes this check, doing so in
'remove_and_add_spares' prevents an additional mutex operation.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

MD RAID5:  Fix kernel oops when RAID4/5/6 is used via device-mapper

Commit a9add5d9 (v3.8-rc1) added blktrace calls to the RAID4/5/6 driver.
However, when device-mapper is used to create RAID4/5/6 arrays, the
mddev->gendisk and mddev->queue fields are not setup.  Therefore, calling
things like trace_block_bio_remap will cause a kernel oops.  This patch
conditionalizes those calls on whether the proper fields exist to make
the calls.  (Device-mapper will call trace_block_bio_remap on its own.)

This patch is suitable for the 3.8.y stable kernel.

Cc: stable@vger.kernel.org (v3.8+)
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

Since commit 1ed850f3
    md/raid5: make sure to_read and to_write never go negative.

It has been possible for handle_stripe_dirtying to be called
when there isn't actually any work to do.
It then calls schedule_reconstruction() which will set R5_LOCKED
on the parity block(s) even when nothing else is happening.
This then causes problems in do_release_stripe().

So add checks to schedule_reconstruction() so that if it doesn't
find anything to do, it just aborts.

This bug was introduced in v3.7, so the patch is suitable
for -stable kernels since then.

Cc: stable@vger.kernel.org (v3.7+)
Reported-by: majianpeng <majianpeng@gmail.com>
Signed-off-by: NeilBrown <neilb@suse.de>

If something has failed while the array was read-auto,
then when we switch to 'active' we need to update the metadata.
This will happen anyway but it is good to expedite it, and
also to ensure any failed device has been released by the
underlying device before we try to action the ioctl which
caused us to switch to 'active' mode.
Reported-by: Joe Lawrence <Joe.Lawrence@stratus.com>
Signed-off-by: NeilBrown <neilb@suse.de>

This doesn't seem to actually help and we have an alternate
multi-threading approach waiting in the wings, so just get
rid of this config option and associated code.

As a bonus, we remove one use of CONFIG_EXPERIMENTAL

Cc: Dan Williams <djbw@fb.com>
Cc: Kees Cook <keescook@chromium.org>
Signed-off-by: NeilBrown <neilb@suse.de>

When raid1/raid10 needs to fix a read error, it first drains
all pending requests by calling freeze_array().
This calls flush_pending_writes() if it needs to sleep,
but some writes may be pending in a per-process plug rather
than in the per-array request queue.

When raid1{,0}_unplug() moves the request from the per-process
plug to the per-array request queue (from which
flush_pending_writes() can flush them), it needs to wake up
freeze_array(), or freeze_array() will never flush them and so
it will block forever.

So add the requires wake_up() calls.

This bug was introduced by commit
   f54a9d0e
for raid1 and a similar commit for RAID10, and so has been present
since linux-3.6.  As the bug causes a deadlock I believe this fix is
suitable for -stable.

Cc: stable@vger.kernel.org (3.6.y 3.7.y 3.8.y)
Reported-by: Tregaron Bayly <tbayly@bluehost.com>
Tested-by: Tregaron Bayly <tbayly@bluehost.com>
Signed-off-by: NeilBrown <neilb@suse.de>

Mentioning "bad disk number -1" exposes irrelevant internal detail.
Just say they are inactive and must be removed.
Signed-off-by: NeilBrown <neilb@suse.de>

Create_stripe_zones returns an error slightly differently to
raid0_run and to raid0_takeover_*.

The error returned used by the second was wrong and an error would
result in mddev->private being set to NULL and sooner or later a
crash.

So never return NULL, return ERR_PTR(err), not NULL from
create_stripe_zones.

This bug has been present since 2.6.35 so the fix is suitable
for any kernel since then.

Cc: stable@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>

You cannot resize a RAID0 array (in terms of making the devices
bigger), but the code doesn't entirely stop you.
So:

 disable setting of the available size on each device for
 RAID0 and Linear devices.  This must not change as doing so
 can change the effective layout of data.

 Make sure that the size that raid0_size() reports is accurate,
 but rounding devices sizes to chunk sizes.  As the device sizes
 cannot change now, this isn't so important, but it is best to be
 safe.

Without this change:
  mdadm --grow /dev/md0 -z max
  mdadm --grow /dev/md0 -Z max
  then read to the end of the array

can cause a BUG in a RAID0 array.

These bugs have been present ever since it became possible
to resize any device, which is a long time.  So the fix is
suitable for any -stable kerenl.

Cc: stable@vger.kernel.org
Signed-off-by: NeilBrown <neilb@suse.de>

DM RAID:  Add support for MD's RAID10 "far" and "offset" algorithms

Until now, dm-raid.c only supported the "near" algorthm of MD's RAID10
implementation.  This patch adds support for the "far" and "offset"
algorithms, but only with the improved redundancy that is brought with
the introduction of the 'use_far_sets' bit, which shifts copied stripes
according to smaller sets vs the entire array.  That is, the 17th bit
of the 'layout' variable that defines the RAID10 implementation will
always be set.   (More information on how the 'layout' variable selects
the RAID10 algorithm can be found in the opening comments of
drivers/md/raid10.c.)
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

MD RAID10:  Improve redundancy for 'far' and 'offset' algorithms (part 2)

This patch addresses raid arrays that have a number of devices that cannot
be evenly divided by 'far_copies'.  (E.g. 5 devices, far_copies = 2)  This
case must be handled differently because it causes that last set to be of
a different size than the rest of the sets.  We must compute a new modulo
for this last set so that copied chunks are properly wrapped around.

Example use_far_sets=1, far_copies=2, near_copies=1, devices=5:
                "far" algorithm
        dev1 dev2 dev3 dev4 dev5
	==== ==== ==== ==== ====
	[ A   B ] [ C    D   E ]
        [ G   H ] [ I    J   K ]
                    ...
        [ B   A ] [ E    C   D ] --> nominal set of 2 and last set of 3
        [ H   G ] [ K    I   J ]     []'s show far/offset sets
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

The MD RAID10 'far' and 'offset' algorithms make copies of entire stripe
widths - copying them to a different location on the same devices after
shifting the stripe.  An example layout of each follows below:

	        "far" algorithm
	dev1 dev2 dev3 dev4 dev5 dev6
	==== ==== ==== ==== ==== ====
	 A    B    C    D    E    F
	 G    H    I    J    K    L
	            ...
	 F    A    B    C    D    E  --> Copy of stripe0, but shifted by 1
	 L    G    H    I    J    K
	            ...

		"offset" algorithm
	dev1 dev2 dev3 dev4 dev5 dev6
	==== ==== ==== ==== ==== ====
	 A    B    C    D    E    F
	 F    A    B    C    D    E  --> Copy of stripe0, but shifted by 1
	 G    H    I    J    K    L
	 L    G    H    I    J    K
	            ...

Redundancy for these algorithms is gained by shifting the copied stripes
one device to the right.  This patch proposes that array be divided into
sets of adjacent devices and when the stripe copies are shifted, they wrap
on set boundaries rather than the array size boundary.  That is, for the
purposes of shifting, the copies are confined to their sets within the
array.  The sets are 'near_copies * far_copies' in size.

The above "far" algorithm example would change to:
	        "far" algorithm
	dev1 dev2 dev3 dev4 dev5 dev6
	==== ==== ==== ==== ==== ====
	 A    B    C    D    E    F
	 G    H    I    J    K    L
	            ...
	 B    A    D    C    F    E  --> Copy of stripe0, shifted 1, 2-dev sets
	 H    G    J    I    L    K      Dev sets are 1-2, 3-4, 5-6
	            ...

This has the affect of improving the redundancy of the array.  We can
always sustain at least one failure, but sometimes more than one can
be handled.  In the first examples, the pairs of devices that CANNOT fail
together are:
	(1,2) (2,3) (3,4) (4,5) (5,6) (1, 6) [40% of possible pairs]
In the example where the copies are confined to sets, the pairs of
devices that cannot fail together are:
	(1,2) (3,4) (5,6)                    [20% of possible pairs]

We cannot simply replace the old algorithms, so the 17th bit of the 'layout'
variable is used to indicate whether we use the old or new method of computing
the shift.  (This is similar to the way the 16th bit indicates whether the
"far" algorithm or the "offset" algorithm is being used.)

This patch only handles the cases where the number of total raid disks is
a multiple of 'far_copies'.  A follow-on patch addresses the condition where
this is not true.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

Changes include assigning 'addr' from 's' instead of 'sector' to be
consistent with the way the code does it just a few lines later and
using '%=' vs a conditional and subtraction.
Signed-off-by: Jonathan Brassow <jbrassow@redhat.com>
Signed-off-by: NeilBrown <neilb@suse.de>

Set mddev queue's max_write_same_sectors to its chunk_sector value (before
disk_stack_limits merges the underlying disk limits.)  With that in place,
be sure to handle writes coming down from the block layer that have the
REQ_WRITE_SAME flag set.  That flag needs to be copied into any newly cloned
write bio.
Signed-off-by: Joe Lawrence <joe.lawrence@stratus.com>
Acked-by: "Martin K. Petersen" <martin.petersen@oracle.com>
Signed-off-by: NeilBrown <neilb@suse.de>

If an fsync occurs on a read-only array, we need to send a
completion for the IO and may not increment the active IO count.
Otherwise, we hit a bug trace and can't stop the MD array anymore.

By advice of Christoph Hellwig we return success upon a flush
request but we return -EROFS for other writes.
We detect flush requests by checking if the bio has zero sectors.

This patch is suitable to any -stable kernel to which it applies.

Cc: Christoph Hellwig <hch@infradead.org>
Cc: Ben Hutchings <ben@decadent.org.uk>
Cc: NeilBrown <neilb@suse.de>
Cc: stable@vger.kernel.org
Signed-off-by: Sebastian Riemer <sebastian.riemer@profitbricks.com>
Reported-by: Ben Hutchings <ben@decadent.org.uk>
Acked-by: Paul Menzel <paulepanter@users.sourceforge.net>
Signed-off-by: NeilBrown <neilb@suse.de>

Pull input subsystem fixes from Dmitry Torokhov:
 "Two small driver fixups and a documentation update for managed input
  devices"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/dtor/input:
  Input: wacom - fix wacom_set_report retry logic
  Input: document that unregistering managed devices is not necessary
  Input: lm8323 - fix checking PWM interrupt status

Commit c060f943 ("mm: use aligned zone start for pfn_to_bitidx
calculation") fixed out calculation of the index into the pageblock
bitmap when a !SPARSEMEM zome was not aligned to pageblock_nr_pages.

However, the _allocation_ of that bitmap had never taken this alignment
requirement into accout, so depending on the exact size and alignment of
the zone, the use of that index could then access past the allocation,
resulting in some very subtle memory corruption.

This was reported (and bisected) by Ingo Molnar: one of his random
config builds would hang with certain very specific kernel command line
options.

In the meantime, commit c060f943 has been marked for stable, so this
fix needs to be back-ported to the stable kernels that backported the
commit to use the right alignment.
Bisected-and-tested-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Mel Gorman <mgorman@suse.de>
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Merge tag 'stable/for-linus-3.8-rc7-tag-two' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen

Pull xen fixes from Konrad Rzeszutek Wilk:
 "Two fixes:

   - A simple bug-fix for redundant NULL check.

   - CVE-2013-0228/XSA-42: x86/xen: don't assume %ds is usable in
     xen_iret for 32-bit PVOPS

  and two reverts:

   - Revert the PVonHVM kexec.  The patch introduces a regression with
     older hypervisor stacks, such as Xen 4.1."

* tag 'stable/for-linus-3.8-rc7-tag-two' of git://git.kernel.org/pub/scm/linux/kernel/git/konrad/xen:
  Revert "xen PVonHVM: use E820_Reserved area for shared_info"
  Revert "xen/PVonHVM: fix compile warning in init_hvm_pv_info"
  xen: remove redundant NULL check before unregister_and_remove_pcpu().
  x86/xen: don't assume %ds is usable in xen_iret for 32-bit PVOPS.

As reported by Klaus Schmidinger:
 "In VDR I use an ioctl() call with FE_READ_UNCORRECTED_BLOCKS on a
  device (using stb0899).  After this call I check 'errno' for
  EOPNOTSUPP to determine whether this device supports this call.  This
  used to work just fine, until a few months ago I noticed that my
  devices using stb0899 didn't display their signal quality in VDR's OSD
  any more.  After further investigation I found that
  ioctl(FE_READ_UNCORRECTED_BLOCKS) no longer returns EOPNOTSUPP, but
  rather ENOTTY.  And since I stop getting the signal quality in case
  any unknown errno value appears, this broke my signal quality query
  function."

While the changes reflect what is there at:

  http://comments.gmane.org/gmane.linux.kernel/1235728

it does cause regression on userspace.  So, revert it to stop the
damage.

This reverts commit 177ffe50 ("[media] dvb_frontend: return -ENOTTY
for unimplement IOCTL").
Reported-by: Klaus Schmidinger <Klaus.Schmidinger@tvdr.de>
Signed-off-by: Mauro Carvalho Chehab <mchehab@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Pull sparc fixes from David Miller:
 "A couple small fixes for sparc including some THP brown-paper-bag
  material:

   1) During the merging of all the THP support for various
      architectures, sparc missed adding a
      HAVE_ARCH_TRANSPARENT_HUGEPAGE to it's Kconfig, oops.

   2) Sparc needs to be mindful of hugepages in get_user_pages_fast().

   3) Fix memory leak in SBUS probe, from Cong Ding.

   4) The sunvdc virtual disk client driver has a test of the bitmask of
      vdisk server supported operations which was off by one bit"

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/sparc:
  sunvdc: Fix off-by-one in generic_request().
  sparc64: Fix get_user_pages_fast() wrt. THP.
  sparc64: Add missing HAVE_ARCH_TRANSPARENT_HUGEPAGE.
  sparc: kernel/sbus.c: fix memory leakage

Pull one more x86 fix from Peter Anvin:
 "Sigh.  One more patch in the "please don't brick my Samsung" series"

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  efi: Clear EFI_RUNTIME_SERVICES rather than EFI_BOOT by "noefi" boot parameter

Pull PCI fix from Bjorn Helgaas:
 "This is another fix for v3.8.  It fixes an oops that happens when a
  Thunderbolt adapter is unplugged (remove device, poll for PME events
  on no-longer-existing device, oops)."

* tag '3.8-pci-fixes-3' of git://git.kernel.org/pub/scm/linux/kernel/git/helgaas/pci:
  PCI/PM: Clean up PME state when removing a device

Pull omapdss fixes from Tomi Valkeinen:
 "It'd be great if these two late fixes would still make it into 3.8.
  The other one fixes ARM kernel compilation when using 'allyesconfig',
  and the other makes DPI displays function again on OMAP3630 boards:

   - Fix ARM compilation with "allyesconfig" (omapdrm: fix the
     dependency to omapdss)

   - fix DPI displays on OMAP3630 (OMAPDSS: add FEAT_DPI_USES_VDDS_DSI
     to omap3630_dss_feat_list)"

* tag 'omapdss-for-3.8-rc8' of git://gitorious.org/linux-omap-dss2/linux:
  omapdrm: fix the dependency to omapdss
  OMAPDSS: add FEAT_DPI_USES_VDDS_DSI to omap3630_dss_feat_list

Pull i2c maintainer info update from Wolfram Sang:
 "Since my old email and repos are not working anymore, and this already
  caused some confusion, I think a MAINTAINERS update for 3.8 is
  helpful.  So, people trying I2C with the new kernel can properly reach
  me and find my repos."

* 'i2c/for-current' of git://git.kernel.org/pub/scm/linux/kernel/git/wsa/linux:
  MAINTAINERS: change my email and repos

This reverts commit 9d02b43d.

We are doing this b/c on 32-bit PVonHVM with older hypervisors
(Xen 4.1) it ends up bothing up the start_info. This is bad b/c
we use it for the time keeping, and the timekeeping code loops
forever - as the version field never changes. Olaf says to
revert it, so lets do that.
Acked-by: Olaf Hering <olaf@aepfle.de>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This reverts commit a7be94ac.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

The 'operations' bitmap corresponds one-for-one with the operation
codes, no adjustment is necessary.
Reported-by: Mark Kettenis <mark.kettenis@xs4all.nl>
Signed-off-by: David S. Miller <davem@davemloft.net>

omapdrm uses "select" in Kconfig to enable omapdss. This doesn't work
correctly, as "select" forces omapdss to be enabled in the config even
if it normally could not be enabled because of missing Kconfig
dependencies.

This causes a build break on ARM, when using allyesconfig:

drivers/video/omap2/dss/dss.c: In function 'dss_calc_clock_div':
drivers/video/omap2/dss/dss.c:572:20: error: 'CONFIG_OMAP2_DSS_MIN_FCK_PER_PCK' undeclared (first use in this function)
drivers/video/omap2/dss/dss.c:572:20: note: each undeclared identifier is reported only once for each function it appears in

Instead of using select, this patch changes omapdrm to use "depend
on".
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

commit 195e672a
   OMAPDSS: DPI: Remove cpu_is_xxxx checks

made the mistake of assuming that cpu_is_omap34xx() is exclusive of
other cpu_is_* predicates whereas it includes cpu_is_omap3630().

So on an omap3630, code that was previously enabled by
  if (cpu_is_omap34xx())
is now disabled as
  dss_has_feature(FEAT_DPI_USES_VDDS_DSI)
fails.

So add FEAT_DPI_USES_VDDS_DSI to omap3630_dss_feat_list.

Cc: Chandrabhanu Mahapatra <cmahapatra@ti.com>
Cc: Tomi Valkeinen <tomi.valkeinen@ti.com>
Signed-off-by: NeilBrown <neilb@suse.de>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>

There was a serious problem in samsung-laptop that its platform driver is
designed to run under BIOS and running under EFI can cause the machine to
become bricked or can cause Machine Check Exceptions.

    Discussion about this problem:
    https://bugs.launchpad.net/ubuntu-cdimage/+bug/1040557
    https://bugzilla.kernel.org/show_bug.cgi?id=47121

    The patches to fix this problem:
    efi: Make 'efi_enabled' a function to query EFI facilities
    83e68189

    samsung-laptop: Disable on EFI hardware
    e0094244

Unfortunately this problem comes back again if users specify "noefi" option.
This parameter clears EFI_BOOT and that driver continues to run even if running
under EFI. Refer to the document, this parameter should clear
EFI_RUNTIME_SERVICES instead.

Documentation/kernel-parameters.txt:
===============================================================================
...
	noefi		[X86] Disable EFI runtime services support.
...
===============================================================================

Documentation/x86/x86_64/uefi.txt:
===============================================================================
...
- If some or all EFI runtime services don't work, you can try following
  kernel command line parameters to turn off some or all EFI runtime
  services.
	noefi		turn off all EFI runtime services
...
===============================================================================
Signed-off-by: Satoru Takeuchi <takeuchi_satoru@jp.fujitsu.com>
Link: http://lkml.kernel.org/r/511C2C04.2070108@jp.fujitsu.com
Cc: Matt Fleming <matt.fleming@intel.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>

unregister_and_remove_pcpu on a NULL pointer is a no-op, so the NULL check in
sync_pcpu can be removed.
Signed-off-by: Cyril Roelandt <tipecaml@gmail.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

This fixes CVE-2013-0228 / XSA-42

Drew Jones while working on CVE-2013-0190 found that that unprivileged guest user
in 32bit PV guest can use to crash the > guest with the panic like this:

-------------
general protection fault: 0000 [#1] SMP
last sysfs file: /sys/devices/vbd-51712/block/xvda/dev
Modules linked in: sunrpc ipt_REJECT nf_conntrack_ipv4 nf_defrag_ipv4
iptable_filter ip_tables ip6t_REJECT nf_conntrack_ipv6 nf_defrag_ipv6
xt_state nf_conntrack ip6table_filter ip6_tables ipv6 xen_netfront ext4
mbcache jbd2 xen_blkfront dm_mirror dm_region_hash dm_log dm_mod [last
unloaded: scsi_wait_scan]

Pid: 1250, comm: r Not tainted 2.6.32-356.el6.i686 #1
EIP: 0061:[<c0407462>] EFLAGS: 00010086 CPU: 0
EIP is at xen_iret+0x12/0x2b
EAX: eb8d0000 EBX: 00000001 ECX: 08049860 EDX: 00000010
ESI: 00000000 EDI: 003d0f00 EBP: b77f8388 ESP: eb8d1fe0
 DS: 0000 ES: 007b FS: 0000 GS: 00e0 SS: 0069
Process r (pid: 1250, ti=eb8d0000 task=c2953550 task.ti=eb8d0000)
Stack:
 00000000 0027f416 00000073 00000206 b77f8364 0000007b 00000000 00000000
Call Trace:
Code: c3 8b 44 24 18 81 4c 24 38 00 02 00 00 8d 64 24 30 e9 03 00 00 00
8d 76 00 f7 44 24 08 00 00 02 80 75 33 50 b8 00 e0 ff ff 21 e0 <8b> 40
10 8b 04 85 a0 f6 ab c0 8b 80 0c b0 b3 c0 f6 44 24 0d 02
EIP: [<c0407462>] xen_iret+0x12/0x2b SS:ESP 0069:eb8d1fe0
general protection fault: 0000 [#2]
---[ end trace ab0d29a492dcd330 ]---
Kernel panic - not syncing: Fatal exception
Pid: 1250, comm: r Tainted: G      D    ---------------
2.6.32-356.el6.i686 #1
Call Trace:
 [<c08476df>] ? panic+0x6e/0x122
 [<c084b63c>] ? oops_end+0xbc/0xd0
 [<c084b260>] ? do_general_protection+0x0/0x210
 [<c084a9b7>] ? error_code+0x73/
-------------

Petr says: "
 I've analysed the bug and I think that xen_iret() cannot cope with
 mangled DS, in this case zeroed out (null selector/descriptor) by either
 xen_failsafe_callback() or RESTORE_REGS because the corresponding LDT
 entry was invalidated by the reproducer. "

Jan took a look at the preliminary patch and came up a fix that solves
this problem:

"This code gets called after all registers other than those handled by
IRET got already restored, hence a null selector in %ds or a non-null
one that got loaded from a code or read-only data descriptor would
cause a kernel mode fault (with the potential of crashing the kernel
as a whole, if panic_on_oops is set)."

The way to fix this is to realize that the we can only relay on the
registers that IRET restores. The two that are guaranteed are the
%cs and %ss as they are always fixed GDT selectors. Also they are
inaccessible from user mode - so they cannot be altered. This is
the approach taken in this patch.

Another alternative option suggested by Jan would be to relay on
the subtle realization that using the %ebp or %esp relative references uses
the %ss segment.  In which case we could switch from using %eax to %ebp and
would not need the %ss over-rides. That would also require one extra
instruction to compensate for the one place where the register is used
as scaled index. However Andrew pointed out that is too subtle and if
further work was to be done in this code-path it could escape folks attention
and lead to accidents.
Reviewed-by: Petr Matousek <pmatouse@redhat.com>
Reported-by: Petr Matousek <pmatouse@redhat.com>
Reviewed-by: Andrew Cooper <andrew.cooper3@citrix.com>
Signed-off-by: Jan Beulich <jbeulich@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

Mostly mirrors the s390 logic, as unlike x86 we don't need the
SetPageReferenced() bits.

On sparc64 we also lack a user/privileged bit in the huge PMDs.

In order to make this work for THP and non-THP builds, some header
file adjustments were necessary.  Namely, provide the PMD_HUGE_* bit
defines and the pmd_large() inline unconditionally rather than
protected by TRANSPARENT_HUGEPAGE.
Reported-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

This got missed in the cleanups done for the S390 THP
support.

CC: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

Pull networking fixes from David Miller:
 "This is primarily to get those r8169 reverts sorted, but other fixes
  have accumulated meanwhile.

   1) Revert two r8169 changes to fix suspend/resume for some users,
      from Francois Romieu.

   2) PCI dma mapping errors in atl1c are not checked for and this cause
      hard crashes for some users, from Xiong Huang.

   3) In 3.8.x we merged the removal of the EXPERIMENTAL dependency for
      'dlm' but the same patch for 'sctp' got lost somewhere, resulting
      in the potential for build errors since there are cross
      dependencies.  From Kees Cook.

   4) SCTP's ipv6 socket route validation makes boolean tests
      incorrectly, fix from Daniel Borkmann.

   5) mac80211 does sizeof(ptr) instead of (sizeof(ptr) * nelem), from
      Cong Ding.

   6) arp_rcv() can crash on shared non-linear packets, from Eric
      Dumazet.

   7) Avoid crashes in macvtap by setting ->gso_type consistently in
      ixgbe, qlcnic, and bnx2x drivers.  From Michael S Tsirkin and
      Alexander Duyck.

   8) Trinity fuzzer spots infinite loop in __skb_recv_datagram(), fix
      from Eric Dumazet.

   9) STP protocol frames should use high packet priority, otherwise an
      overloaded bridge can get stuck.  From Stephen Hemminger.

  10) The HTB packet scheduler was converted some time ago to store
      internal timestamps in nanoseconds, but we don't convert back into
      psched ticks for the user during dumps.  Fix from Jiri Pirko.

  11) mwl8k channel table doesn't set the .band field properly,
      resulting in NULL pointer derefs.  Fix from Jonas Gorski.

  12) mac80211 doesn't accumulate channels properly during a scan so we
      can downgrade heavily to a much less desirable connection speed.
      Fix from Johannes Berg.

  13) PHY probe failure in stmmac can result in resource leaks and
      double MDIO registery later, from Giuseppe CAVALLARO.

  14) Correct ipv6 checksumming in ip6t_NPT netfilter module, also fix
      address prefix mangling, from YOSHIFUJI Hideaki."

* git://git.kernel.org/pub/scm/linux/kernel/git/davem/net: (27 commits)
  net, sctp: remove CONFIG_EXPERIMENTAL
  net: sctp: sctp_v6_get_dst: fix boolean test in dst cache
  batman-adv: Fix NULL pointer dereference in DAT hash collision avoidance
  net/macb: fix race with RX interrupt while doing NAPI
  atl1c: add error checking for pci_map_single functions
  htb: fix values in opt dump
  ixgbe: Only set gso_type to SKB_GSO_TCPV4 as RSC does not support IPv6
  net: fix infinite loop in __skb_recv_datagram()
  net: qmi_wwan: add Yota / Megafon M100-1 4g modem
  mwl8k: fix band for supported channels
  bridge: set priority of STP packets
  mac80211: fix channel selection bug
  arp: fix possible crash in arp_rcv()
  bnx2x: set gso_type
  qlcnic: set gso_type
  ixgbe: fix gso type
  stmmac: mdio register has to fail if the phy is not found
  stmmac: fix macro used for debugging the xmit
  Revert "r8169: enable internal ASPM and clock request settings".
  Revert "r8169: enable ALDPS for power saving".
  ...

Pull x86 fixes from Peter Anvin:
 "One (hopefully) last batch of x86 fixes.  You asked for the patch by
  patch justifications, so here they are:

      x86, MCE: Retract most UAPI exports

   This one unexports from userspace a bunch of definitions which should
   never have been exported.  We really don't want to create an
   accidental legacy here.

      x86, doc: Add a bootloader ID for OVMF

   This is a documentation-only patch, just recording the official
   assignment of a boot loader ID.

      x86: Do not leak kernel page mapping locations

   Security: avoid making it needlessly easy for user space to probe the
   kernel memory layout.

      x86/mm: Check if PUD is large when validating a kernel address

   Prevent failures using /proc/kcore when using 1G pages.

      x86/apic: Work around boot failure on HP ProLiant DL980 G7 Server systems

   Works around a BIOS problem causing boot failures on affected hardware."

* 'x86-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  x86/mm: Check if PUD is large when validating a kernel address
  x86/apic: Work around boot failure on HP ProLiant DL980 G7 Server systems
  x86, doc: Add a bootloader ID for OVMF
  x86: Do not leak kernel page mapping locations
  x86, MCE: Retract most UAPI exports

Change to my private email, change to my shiny new kernel.org repos,
and drop outdated entry from the former maintainer. Drop my PCA entry,
too, since it belongs to the I2C realm anyhow.
Signed-off-by: Wolfram Sang <wolfram@the-dreams.de>

Devices are added to pci_pme_list when drivers use pci_enable_wake()
or pci_wake_from_d3(), but they aren't removed from the list unless
the driver explicitly disables wakeup.  Many drivers never disable
wakeup, so their devices remain on the list even after they are
removed, e.g., via hotplug.  A subsequent PME poll will oops when
it tries to touch the device.

This patch disables PME# on a device before removing it, which removes
the device from pci_pme_list.  This is safe even if the device never
had PME# enabled.

This oops can be triggered by unplugging a Thunderbolt ethernet adapter
on a Macbook Pro, as reported by Daniel below.

[bhelgaas: changelog]
Reference: http://lkml.kernel.org/r/CAMVG2svG21yiM1wkH4_2pen2n+cr2-Zv7TbH3Gj+8MwevZjDbw@mail.gmail.comReported-and-tested-by: Daniel J Blueman <daniel@quora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
CC: stable@vger.kernel.org