commit 3fa6993f upstream.

The user timer tu->qused counter may go to a negative value when
multiple concurrent reads are performed since both the check and the
decrement of tu->qused are done in two individual locked contexts.
This results in bogus read outs, and the endless loop in the
user-space side.

The fix is to move the decrement of the tu->qused counter into the
same spinlock context as the zero-check of the counter.
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit f87fda00 upstream.

ether_addr_equal_64bits() requires some care about its arguments,
namely that 8 bytes might be read, even if last 2 byte values are not
used.

KASan detected a violation with null_mac_addr and lacpdu_mcast_addr
in bond_3ad.c

Same problem with mac_bcast[] and mac_v6_allmcast[] in bond_alb.c :
Although the 8-byte alignment was there, KASan would detect out
of bound accesses.

Fixes: 815117ad ("bonding: use ether_addr_equal_unaligned for bond addr compare")
Fixes: bb54e589 ("bonding: Verify RX LACPDU has proper dest mac-addr")
Fixes: 885a136c ("bonding: use compare_ether_addr_64bits() in ALB")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Dmitry Vyukov <dvyukov@google.com>
Acked-by: Nikolay Aleksandrov <nikolay@cumulusnetworks.com>
Acked-by: Ding Tianhong <dingtianhong@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2:
 - Adjust filename
 - Drop change to bond_params::ad_actor_system
 - Fix one more copy of null_mac_addr to use eth_zero_addr()]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 6d57e907 upstream.

a lot of code has either the memset or an inefficient copy
from a static array that contains the all-zeros Ethernet address.
Introduce help function eth_zero_addr() to fill an address with
all zeros, making the code clearer and allowing us to get rid of
some constant arrays.
Signed-off-by: Duan Jiong <djduanjiong@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 1ead852d upstream.

Fix boot crash that triggers if this driver is built into a kernel and
run on non-AMD systems.

AMD northbridges users call amd_cache_northbridges() and it returns
a negative value to signal that we weren't able to cache/detect any
northbridges on the system.

At least, it should do so as all its callers expect it to do so. But it
does return a negative value only when kmalloc() fails.

Fix it to return -ENODEV if there are no NBs cached as otherwise, amd_nb
users like amd64_edac, for example, which relies on it to know whether
it should load or not, gets loaded on systems like Intel Xeons where it
shouldn't.
Reported-and-tested-by: Tony Battersby <tonyb@cybernetics.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1466097230-5333-2-git-send-email-bp@alien8.de
Link: https://lkml.kernel.org/r/5761BEB0.9000807@cybernetics.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 62db7152 upstream.

vortex_wtdma_bufshift() function does calculate the page index
wrongly, first masking then shift, which always results in zero.
The proper computation is to first shift, then mask.
Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 9c4604a2 upstream.

The tt_req_node is added and removed from a list inside a spinlock. But the
locking is sometimes removed even when the object is still referenced and
will be used later via this reference. For example batadv_send_tt_request
can create a new tt_req_node (including add to a list) and later
re-acquires the lock to remove it from the list and to free it. But at this
time another context could have already removed this tt_req_node from the
list and freed it.

CPU#0

    batadv_batman_skb_recv from net_device 0
    -> batadv_iv_ogm_receive
      -> batadv_iv_ogm_process
        -> batadv_iv_ogm_process_per_outif
          -> batadv_tvlv_ogm_receive
            -> batadv_tvlv_ogm_receive
              -> batadv_tvlv_containers_process
                -> batadv_tvlv_call_handler
                  -> batadv_tt_tvlv_ogm_handler_v1
                    -> batadv_tt_update_orig
                      -> batadv_send_tt_request
                        -> batadv_tt_req_node_new
                           spin_lock(...)
                           allocates new tt_req_node and adds it to list
                           spin_unlock(...)
                           return tt_req_node

CPU#1

    batadv_batman_skb_recv from net_device 1
    -> batadv_recv_unicast_tvlv
      -> batadv_tvlv_containers_process
        -> batadv_tvlv_call_handler
          -> batadv_tt_tvlv_unicast_handler_v1
            -> batadv_handle_tt_response
               spin_lock(...)
               tt_req_node gets removed from list and is freed
               spin_unlock(...)

CPU#0

                      <- returned to batadv_send_tt_request
                         spin_lock(...)
                         tt_req_node gets removed from list and is freed
                         MEMORY CORRUPTION/SEGFAULT/...
                         spin_unlock(...)

This can only be solved via reference counting to allow multiple contexts
to handle the list manipulation while making sure that only the last
context holding a reference will free the object.

Fixes: a73105b8 ("batman-adv: improved client announcement mechanism")
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Tested-by: Martin Weinelt <martin@darmstadt.freifunk.net>
Tested-by: Amadeus Alfa <amadeus@chemnitz.freifunk.net>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: David S. Miller <davem@davemloft.net>
[bwh: Backported to 3.2:
 - Adjust context
 - Use struct tt_req_node instead of struct batadv_tt_req_node
 - Use list_empty() instead of hlist_unhashed()
 - Drop kernel-doc change]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit e547f262 upstream.

Olga Kornievskaia reports that the following test fails to trigger
an OPEN_DOWNGRADE on the wire, and only triggers the final CLOSE.

	fd0 = open(foo, RDRW)   -- should be open on the wire for "both"
	fd1 = open(foo, RDONLY)  -- should be open on the wire for "read"
	close(fd0) -- should trigger an open_downgrade
	read(fd1)
	close(fd1)

The issue is that we're missing a check for whether or not the current
state transitioned from an O_RDWR state as opposed to having transitioned
from a combination of O_RDONLY and O_WRONLY.
Reported-by: Olga Kornievskaia <aglo@umich.edu>
Fixes: cd9288ff ("NFSv4: Fix another bug in the close/open_downgrade code")
Signed-off-by: Trond Myklebust <trond.myklebust@primarydata.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 9c6795a9 upstream.

'commpage_bak' is allocated with 'sizeof(struct echoaudio)' bytes.
We then copy 'sizeof(struct comm_page)' bytes in it.
On my system, smatch complains because one is 2960 and the other is 3072.

This would result in memory corruption or a oops.
Signed-off-by: Christophe JAILLET <christophe.jaillet@wanadoo.fr>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 0c1f91b9 upstream.

These two spi_w8r8() calls return a value with is used by the code
following the error check. The dubious use was caused by a cleanup
patch.

Fixes: d34dbee8 ("staging:iio:accel:kxsd9 cleanup and conversion to iio_chan_spec.")
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit ef3149eb upstream.

sca3000_read_ctrl_reg() returns a negative number on failure, check for
this instead of zero.
Signed-off-by: Luis de Bethencourt <luisbg@osg.samsung.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 63d2f95d upstream.

The value `bytes' comes from the filesystem which is about to be
mounted.  We cannot trust that the value is always in the range we
expect it to be.

Check its value before using it to calculate the length for the crc32_le
call.  It value must be larger (or equal) sumoff + 4.

This fixes a kernel bug when accidentially mounting an image file which
had the nilfs2 magic value 0x3434 at the right offset 0x406 by chance.
The bytes 0x01 0x00 were stored at 0x408 and were interpreted as a
s_bytes value of 1.  This caused an underflow when substracting sumoff +
4 (20) in the call to crc32_le.

  BUG: unable to handle kernel paging request at ffff88021e600000
  IP:  crc32_le+0x36/0x100
  ...
  Call Trace:
    nilfs_valid_sb.part.5+0x52/0x60 [nilfs2]
    nilfs_load_super_block+0x142/0x300 [nilfs2]
    init_nilfs+0x60/0x390 [nilfs2]
    nilfs_mount+0x302/0x520 [nilfs2]
    mount_fs+0x38/0x160
    vfs_kern_mount+0x67/0x110
    do_mount+0x269/0xe00
    SyS_mount+0x9f/0x100
    entry_SYSCALL_64_fastpath+0x16/0x71

Link: http://lkml.kernel.org/r/1466778587-5184-2-git-send-email-konishi.ryusuke@lab.ntt.co.jpSigned-off-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Tested-by: Torsten Hilbrich <torsten.hilbrich@secunet.com>
Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit d5dbbe65 upstream.

syzkaller fuzzer spotted a potential use-after-free case in snd-dummy
driver when hrtimer is used as backend:
> ==================================================================
> BUG: KASAN: use-after-free in rb_erase+0x1b17/0x2010 at addr ffff88005e5b6f68
>  Read of size 8 by task syz-executor/8984
> =============================================================================
> BUG kmalloc-192 (Not tainted): kasan: bad access detected
> -----------------------------------------------------------------------------
>
> Disabling lock debugging due to kernel taint
> INFO: Allocated in 0xbbbbbbbbbbbbbbbb age=18446705582212484632
> ....
> [<      none      >] dummy_hrtimer_create+0x49/0x1a0 sound/drivers/dummy.c:464
> ....
> INFO: Freed in 0xfffd8e09 age=18446705496313138713 cpu=2164287125 pid=-1
> [<      none      >] dummy_hrtimer_free+0x68/0x80 sound/drivers/dummy.c:481
> ....
> Call Trace:
>  [<ffffffff8179e59e>] __asan_report_load8_noabort+0x3e/0x40 mm/kasan/report.c:333
>  [<     inline     >] rb_set_parent include/linux/rbtree_augmented.h:111
>  [<     inline     >] __rb_erase_augmented include/linux/rbtree_augmented.h:218
>  [<ffffffff82ca5787>] rb_erase+0x1b17/0x2010 lib/rbtree.c:427
>  [<ffffffff82cb02e8>] timerqueue_del+0x78/0x170 lib/timerqueue.c:86
>  [<ffffffff814d0c80>] __remove_hrtimer+0x90/0x220 kernel/time/hrtimer.c:903
>  [<     inline     >] remove_hrtimer kernel/time/hrtimer.c:945
>  [<ffffffff814d23da>] hrtimer_try_to_cancel+0x22a/0x570 kernel/time/hrtimer.c:1046
>  [<ffffffff814d2742>] hrtimer_cancel+0x22/0x40 kernel/time/hrtimer.c:1066
>  [<ffffffff85420531>] dummy_hrtimer_stop+0x91/0xb0 sound/drivers/dummy.c:417
>  [<ffffffff854228bf>] dummy_pcm_trigger+0x17f/0x1e0 sound/drivers/dummy.c:507
>  [<ffffffff85392170>] snd_pcm_do_stop+0x160/0x1b0 sound/core/pcm_native.c:1106
>  [<ffffffff85391b26>] snd_pcm_action_single+0x76/0x120 sound/core/pcm_native.c:956
>  [<ffffffff85391e01>] snd_pcm_action+0x231/0x290 sound/core/pcm_native.c:974
>  [<     inline     >] snd_pcm_stop sound/core/pcm_native.c:1139
>  [<ffffffff8539754d>] snd_pcm_drop+0x12d/0x1d0 sound/core/pcm_native.c:1784
>  [<ffffffff8539d3be>] snd_pcm_common_ioctl1+0xfae/0x2150 sound/core/pcm_native.c:2805
>  [<ffffffff8539ee91>] snd_pcm_capture_ioctl1+0x2a1/0x5e0 sound/core/pcm_native.c:2976
>  [<ffffffff8539f2ec>] snd_pcm_kernel_ioctl+0x11c/0x160 sound/core/pcm_native.c:3020
>  [<ffffffff853d9a44>] snd_pcm_oss_sync+0x3a4/0xa30 sound/core/oss/pcm_oss.c:1693
>  [<ffffffff853da27d>] snd_pcm_oss_release+0x1ad/0x280 sound/core/oss/pcm_oss.c:2483
>  .....

A workaround is to call hrtimer_cancel() in dummy_hrtimer_sync() which
is called certainly before other blocking ops.
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Tested-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 93a2001b upstream.

This patch validates the num_values parameter from userland during the
HIDIOCGUSAGES and HIDIOCSUSAGES commands. Previously, if the report id was set
to HID_REPORT_ID_UNKNOWN, we would fail to validate the num_values parameter
leading to a heap overflow.
Signed-off-by: Scott Bauer <sbauer@plzdonthack.me>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 226ba707 upstream.

The touchpad in HP Pavilion 14-ab057ca reports it's version as 12 and
according to Elan both 11 and 12 are valid IC types and should be
identified as hw_version 4.
Reported-by: Patrick Lessard <Patrick.Lessard@cogeco.com>
Tested-by: Patrick Lessard <Patrick.Lessard@cogeco.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 12afb344 upstream.

Somehow the patch that added two-finger touch support forgot to update
W8001_MAX_LENGTH from 11 to 13.
Signed-off-by: Ping Cheng <pingc@wacom.com>
Reviewed-by: Peter Hutterer <peter.hutterer@who-t.net>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit f2940e2c upstream.

When calculating the required size of an RC QP send queue, leave
enough space for masked atomic operations, which require more space than
"regular" atomic operation.

Fixes: 6fa8f719 ("IB/mlx4: Add support for masked atomic operations")
Signed-off-by: Yishai Hadas <yishaih@mellanox.com>
Reviewed-by: Jack Morgenstein <jackm@mellanox.co.il>
Reviewed-by: Eran Ben Elisha <eranbe@mellanox.com>
Signed-off-by: Leon Romanovsky <leon@kernel.org>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 02ef871e upstream.

Current overlap check is evaluating to false a case where a filter
field is fully contained (proper subset) of a r/w request.  This
change applies classical overlap check instead to include all the
scenarios.

More specifically, for (Hilscher GmbH CIFX 50E-DP(M/S)) device driver
the logic is such that the entire confspace is read and written in 4
byte chunks. In this case as an example, CACHE_LINE_SIZE,
LATENCY_TIMER and PCI_BIST are arriving together in one call to
xen_pcibk_config_write() with offset == 0xc and size == 4.  With the
exsisting overlap check the LATENCY_TIMER field (offset == 0xd, length
== 1) is fully contained in the write request and hence is excluded
from write, which is incorrect.
Signed-off-by: Andrey Grodzovsky <andrey2805@gmail.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Reviewed-by: Jan Beulich <JBeulich@suse.com>
Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 25e1ed6e upstream.

For 'real' hardware CAN devices the netlink interface is used to set CAN
specific communication parameters. Real CAN hardware can not be created nor
removed with the ip tool ...

This patch adds a private dellink function for the CAN device driver interface
that does just nothing.

It's a follow up to commit 993e6f2f ("can: fix oops caused by wrong rtnl
newlink usage") but for dellink.
Reported-by: ajneu <ajneu1@gmail.com>
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 4ac1c17b upstream.

During page migrations UBIFS might get confused
and the following assert triggers:
[  213.480000] UBIFS assert failed in ubifs_set_page_dirty at 1451 (pid 436)
[  213.490000] CPU: 0 PID: 436 Comm: drm-stress-test Not tainted 4.4.4-00176-geaa802524636-dirty #1008
[  213.490000] Hardware name: Allwinner sun4i/sun5i Families
[  213.490000] [<c0015e70>] (unwind_backtrace) from [<c0012cdc>] (show_stack+0x10/0x14)
[  213.490000] [<c0012cdc>] (show_stack) from [<c02ad834>] (dump_stack+0x8c/0xa0)
[  213.490000] [<c02ad834>] (dump_stack) from [<c0236ee8>] (ubifs_set_page_dirty+0x44/0x50)
[  213.490000] [<c0236ee8>] (ubifs_set_page_dirty) from [<c00fa0bc>] (try_to_unmap_one+0x10c/0x3a8)
[  213.490000] [<c00fa0bc>] (try_to_unmap_one) from [<c00fadb4>] (rmap_walk+0xb4/0x290)
[  213.490000] [<c00fadb4>] (rmap_walk) from [<c00fb1bc>] (try_to_unmap+0x64/0x80)
[  213.490000] [<c00fb1bc>] (try_to_unmap) from [<c010dc28>] (migrate_pages+0x328/0x7a0)
[  213.490000] [<c010dc28>] (migrate_pages) from [<c00d0cb0>] (alloc_contig_range+0x168/0x2f4)
[  213.490000] [<c00d0cb0>] (alloc_contig_range) from [<c010ec00>] (cma_alloc+0x170/0x2c0)
[  213.490000] [<c010ec00>] (cma_alloc) from [<c001a958>] (__alloc_from_contiguous+0x38/0xd8)
[  213.490000] [<c001a958>] (__alloc_from_contiguous) from [<c001ad44>] (__dma_alloc+0x23c/0x274)
[  213.490000] [<c001ad44>] (__dma_alloc) from [<c001ae08>] (arm_dma_alloc+0x54/0x5c)
[  213.490000] [<c001ae08>] (arm_dma_alloc) from [<c035cecc>] (drm_gem_cma_create+0xb8/0xf0)
[  213.490000] [<c035cecc>] (drm_gem_cma_create) from [<c035cf20>] (drm_gem_cma_create_with_handle+0x1c/0xe8)
[  213.490000] [<c035cf20>] (drm_gem_cma_create_with_handle) from [<c035d088>] (drm_gem_cma_dumb_create+0x3c/0x48)
[  213.490000] [<c035d088>] (drm_gem_cma_dumb_create) from [<c0341ed8>] (drm_ioctl+0x12c/0x444)
[  213.490000] [<c0341ed8>] (drm_ioctl) from [<c0121adc>] (do_vfs_ioctl+0x3f4/0x614)
[  213.490000] [<c0121adc>] (do_vfs_ioctl) from [<c0121d30>] (SyS_ioctl+0x34/0x5c)
[  213.490000] [<c0121d30>] (SyS_ioctl) from [<c000f2c0>] (ret_fast_syscall+0x0/0x34)

UBIFS is using PagePrivate() which can have different meanings across
filesystems. Therefore the generic page migration code cannot handle this
case correctly.
We have to implement our own migration function which basically does a
plain copy but also duplicates the page private flag.
UBIFS is not a block device filesystem and cannot use buffer_migrate_page().
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
[rw: Massaged changelog, build fixes, etc...]
Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Christoph Hellwig <hch@lst.de>
[bwh: Backported to 3.2:
 - migrate_page_move_mapping() doesn't take an extra_count parameter
 - Use literal 0 instead of MIGRATEPAGE_SUCCESS]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 1118dce7 upstream.

Export these symbols such that UBIFS can implement
->migratepage.
Signed-off-by: Richard Weinberger <richard@nod.at>
Acked-by: Christoph Hellwig <hch@lst.de>
[bwh: Backported to 3.2: also change migrate_page_move_mapping() from
 static to extern, done as part of an earlier commit upstream]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 972228d8 upstream.

recover_peb() was never power cut aware,
if a power cut happened right after writing the VID header
upon next attach UBI would blindly use the new partial written
PEB and all data from the old PEB is lost.

In order to make recover_peb() power cut aware, write the new
VID with a proper crc and copy_flag set such that the UBI attach
process will detect whether the new PEB is completely written
or not.
We cannot directly use ubi_eba_atomic_leb_change() since we'd
have to unlock the LEB which is facing a write error.
Reported-by: Jörg Pfähler <pfaehler@isse.de>
Reviewed-by: Jörg Pfähler <pfaehler@isse.de>
Signed-off-by: Richard Weinberger <richard@nod.at>
[bwh: Backported to 3.2:
 - Adjust context
 - Use next_sqnum() instead of ubi_next_sqnum()
 - Use ubi_device::peb_buf1 instead of ubi_device::peb_buf
 - No need to unlock ubi->fm_eba_sem on error]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 43200a44 upstream.

At high bus load it could happen that "at91_poll()" enters with all RX
message boxes filled up. If then at the end the "quota" is exceeded as
well, "rx_next" will not be reset to the first RX mailbox and hence the
interrupts remain disabled.
Signed-off-by: Wolfgang Grandegger <wg@grandegger.com>
Tested-by: Amr Bekhit <amrbekhit@gmail.com>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 7613663c upstream.

For security reasons ordinary user must not be able to control fan speed
via /proc/i8k by default. Some malicious software running under "nobody"
user could be able to turn fan off and cause HW problems. So this patch
changes default value of "restricted" parameter to 1.

Also restrict reading of DMI_PRODUCT_SERIAL from /proc/i8k via "restricted"
parameter. It is because non root user cannot read DMI_PRODUCT_SERIAL from
sysfs file /sys/class/dmi/id/product_serial.

Old non secure behaviour of file /proc/i8k can be achieved by loading this
module with "restricted" parameter set to 0.

Note that this patch has effects only for kernels compiled with CONFIG_I8K
and only for file /proc/i8k. Hwmon interface provided by this driver was
not changed and root access for setting fan speed was needed also before.
Reported-by: Mario Limonciello <Mario_Limonciello@dell.com>
Signed-off-by: Pali Rohár <pali.rohar@gmail.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 32a5a0c0 upstream.

The isa_bus_init function must be called before drivers which utilize
the ISA bus driver are registered. A race condition for initilization
exists if device_initcall is used (the isa_bus_init callback is placed
in the same initcall level as dependent drivers which use module_init).
This patch ensures that isa_bus_init is called first by utilizing
postcore_initcall in favor of device_initcall.

Fixes: a5117ba7 ("[PATCH] Driver model: add ISA bus")
Cc: Rene Herman <rene.herman@keyaccess.nl>
Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 8c5122e4 upstream.

When this code was reworked for IBoE support the order of assignments
for the sl_tclass_flowlabel got flipped around resulting in
TClass & FlowLabel being permanently set to 0 in the packet headers.

This breaks IB routers that rely on these headers, but only affects
kernel users - libmlx4 does this properly for user space.

Fixes: fa417f7b ("IB/mlx4: Add support for IBoE")
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 38327424 upstream.

If __key_link_begin() failed then "edit" would be uninitialized.  I've
added a check to fix that.

This allows a random user to crash the kernel, though it's quite
difficult to achieve.  There are three ways it can be done as the user
would have to cause an error to occur in __key_link():

 (1) Cause the kernel to run out of memory.  In practice, this is difficult
     to achieve without ENOMEM cropping up elsewhere and aborting the
     attempt.

 (2) Revoke the destination keyring between the keyring ID being looked up
     and it being tested for revocation.  In practice, this is difficult to
     time correctly because the KEYCTL_REJECT function can only be used
     from the request-key upcall process.  Further, users can only make use
     of what's in /sbin/request-key.conf, though this does including a
     rejection debugging test - which means that the destination keyring
     has to be the caller's session keyring in practice.

 (3) Have just enough key quota available to create a key, a new session
     keyring for the upcall and a link in the session keyring, but not then
     sufficient quota to create a link in the nominated destination keyring
     so that it fails with EDQUOT.

The bug can be triggered using option (3) above using something like the
following:

	echo 80 >/proc/sys/kernel/keys/root_maxbytes
	keyctl request2 user debug:fred negate @t

The above sets the quota to something much lower (80) to make the bug
easier to trigger, but this is dependent on the system.  Note also that
the name of the keyring created contains a random number that may be
between 1 and 10 characters in size, so may throw the test off by
changing the amount of quota used.

Assuming the failure occurs, something like the following will be seen:

	kfree_debugcheck: out of range ptr 6b6b6b6b6b6b6b68h
	------------[ cut here ]------------
	kernel BUG at ../mm/slab.c:2821!
	...
	RIP: 0010:[<ffffffff811600f9>] kfree_debugcheck+0x20/0x25
	RSP: 0018:ffff8804014a7de8  EFLAGS: 00010092
	RAX: 0000000000000034 RBX: 6b6b6b6b6b6b6b68 RCX: 0000000000000000
	RDX: 0000000000040001 RSI: 00000000000000f6 RDI: 0000000000000300
	RBP: ffff8804014a7df0 R08: 0000000000000001 R09: 0000000000000000
	R10: ffff8804014a7e68 R11: 0000000000000054 R12: 0000000000000202
	R13: ffffffff81318a66 R14: 0000000000000000 R15: 0000000000000001
	...
	Call Trace:
	  kfree+0xde/0x1bc
	  assoc_array_cancel_edit+0x1f/0x36
	  __key_link_end+0x55/0x63
	  key_reject_and_link+0x124/0x155
	  keyctl_reject_key+0xb6/0xe0
	  keyctl_negate_key+0x10/0x12
	  SyS_keyctl+0x9f/0xe7
	  do_syscall_64+0x63/0x13a
	  entry_SYSCALL64_slow_path+0x25/0x25

Fixes: f70e2e06 ('KEYS: Do preallocation for __key_link()')
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit caf1ff26 upstream.

These days, we experienced one guest crash with 8 cores and 3 disks,
with qemu error logs as bellow:

qemu-system-x86_64: /build/qemu-2.0.0/kvm-all.c:984:
kvm_irqchip_commit_routes: Assertion `ret == 0' failed.

And then we found one patch(bdf026317d) in qemu tree, which said
could fix this bug.

Execute the following script will reproduce the BUG quickly:

irq_affinity.sh
========================================================================

vda_irq_num=25
vdb_irq_num=27
while [ 1 ]
do
    for irq in {1,2,4,8,10,20,40,80}
        do
            echo $irq > /proc/irq/$vda_irq_num/smp_affinity
            echo $irq > /proc/irq/$vdb_irq_num/smp_affinity
            dd if=/dev/vda of=/dev/zero bs=4K count=100 iflag=direct
            dd if=/dev/vdb of=/dev/zero bs=4K count=100 iflag=direct
        done
done
========================================================================

The following qemu log is added in the qemu code and is displayed when
this bug reproduced:

kvm_irqchip_commit_routes: max gsi: 1008, nr_allocated_irq_routes: 1024,
irq_routes->nr: 1024, gsi_count: 1024.

That's to say when irq_routes->nr == 1024, there are 1024 routing entries,
but in the kernel code when routes->nr >= 1024, will just return -EINVAL;

The nr is the number of the routing entries which is in of
[1 ~ KVM_MAX_IRQ_ROUTES], not the index in [0 ~ KVM_MAX_IRQ_ROUTES - 1].

This patch fix the BUG above.
Signed-off-by: Xiubo Li <lixiubo@cmss.chinamobile.com>
Signed-off-by: Wei Tang <tangwei@cmss.chinamobile.com>
Signed-off-by: Zhang Zhuoyu <zhangzhuoyu@cmss.chinamobile.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 7e1b1fc4 upstream.

Modules which register drivers via standard path (driver_register) in
parallel can cause a warning:
WARNING: CPU: 2 PID: 3492 at ../fs/sysfs/dir.c:31 sysfs_warn_dup+0x62/0x80
sysfs: cannot create duplicate filename '/module/saa7146/drivers'
Modules linked in: hexium_gemini(+) mxb(+) ...
...
Call Trace:
...
 [<ffffffff812e63a2>] sysfs_warn_dup+0x62/0x80
 [<ffffffff812e6487>] sysfs_create_dir_ns+0x77/0x90
 [<ffffffff8140f2c4>] kobject_add_internal+0xb4/0x340
 [<ffffffff8140f5b8>] kobject_add+0x68/0xb0
 [<ffffffff8140f631>] kobject_create_and_add+0x31/0x70
 [<ffffffff8157a703>] module_add_driver+0xc3/0xd0
 [<ffffffff8155e5d4>] bus_add_driver+0x154/0x280
 [<ffffffff815604c0>] driver_register+0x60/0xe0
 [<ffffffff8145bed0>] __pci_register_driver+0x60/0x70
 [<ffffffffa0273e14>] saa7146_register_extension+0x64/0x90 [saa7146]
 [<ffffffffa0033011>] hexium_init_module+0x11/0x1000 [hexium_gemini]
...

As can be (mostly) seen, driver_register causes this call sequence:
  -> bus_add_driver
    -> module_add_driver
      -> module_create_drivers_dir
The last one creates "drivers" directory in /sys/module/<...>. When
this is done in parallel, the directory is attempted to be created
twice at the same time.

This can be easily reproduced by loading mxb and hexium_gemini in
parallel:
while :; do
  modprobe mxb &
  modprobe hexium_gemini
  wait
  rmmod mxb hexium_gemini saa7146_vv saa7146
done

saa7146 calls pci_register_driver for both mxb and hexium_gemini,
which means /sys/module/saa7146/drivers is to be created for both of
them.

Fix this by a new mutex in module_create_drivers_dir which makes the
test-and-create "drivers" dir atomic.

I inverted the condition and removed 'return' to avoid multiple
unlocks or a goto.
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
Fixes: fe480a26 (Modules: only add drivers/ direcory if needed)
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 57675cb9 upstream.

Lengthy output of sysrq-w may take a lot of time on slow serial console.

Currently we reset NMI-watchdog on the current CPU to avoid spurious
lockup messages. Sometimes this doesn't work since softlockup watchdog
might trigger on another CPU which is waiting for an IPI to proceed.
We reset softlockup watchdogs on all CPUs, but we do this only after
listing all tasks, and this may be too late on a busy system.

So, reset watchdogs CPUs earlier, in for_each_process_thread() loop.
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1465474805-14641-1-git-send-email-aryabinin@virtuozzo.comSigned-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.2: adjust filename, context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit dcfc4724 upstream.

Fix kprobe_fault_handler() to clear the TF (trap flag) bit of
the flags register in the case of a fault fixup on single-stepping.

If we put a kprobe on the instruction which caused a
page fault (e.g. actual mov instructions in copy_user_*),
that fault happens on the single-stepping buffer. In this
case, kprobes resets running instance so that the CPU can
retry execution on the original ip address.

However, current code forgets to reset the TF bit. Since this
fault happens with TF bit set for enabling single-stepping,
when it retries, it causes a debug exception and kprobes
can not handle it because it already reset itself.

On the most of x86-64 platform, it can be easily reproduced
by using kprobe tracer. E.g.

  # cd /sys/kernel/debug/tracing
  # echo p copy_user_enhanced_fast_string+5 > kprobe_events
  # echo 1 > events/kprobes/enable

And you'll see a kernel panic on do_debug(), since the debug
trap is not handled by kprobes.

To fix this problem, we just need to clear the TF bit when
resetting running kprobe.
Signed-off-by: Masami Hiramatsu <mhiramat@kernel.org>
Reviewed-by: Ananth N Mavinakayanahalli <ananth@linux.vnet.ibm.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: systemtap@sourceware.org
Link: http://lkml.kernel.org/r/20160611140648.25885.37482.stgit@devbox
[ Updated the comments. ]
Signed-off-by: Ingo Molnar <mingo@kernel.org>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 05082b8b upstream.

When executing in a PCI passthrough based virtuzliation environment, the
hypervisor will usually attempt to send a PCIe bus reset signal to the
ASIC when the VM reboots. In this scenario, the card is not correctly
initialized, but we still consider it to be posted. Therefore, in a
passthrough based environemnt we should always post the card to guarantee
it is in a good state for driver initialization.

Ported from amdgpu commit:
amdgpu: fix asic initialization for virtualized environments

Cc: Andres Rodriguez <andres.rodriguez@amd.com>
Cc: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 99543823 upstream.

When attaching a pollfunc iio_trigger_attach_poll_func will allocate a
virtual irq and call the driver's set_trigger_state function. Fix error
handling to undo previous steps if any fails.

In particular this fixes handling errors from a driver's
set_trigger_state function. When using triggered buffers a failure to
enable the trigger used to make the buffer unusable.
Signed-off-by: Crestez Dan Leonard <leonard.crestez@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
[bwh: Backported to 3.2: adjust filename]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 5dd72ecb upstream.

Both of these are decidedly silly bugs show up whilst testing
completely different code paths.
Signed-off-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 7b2c17f8 upstream.

Ensure that the endpoint is stopped by clearing REQPKT before
clearing DATAERR_NAKTIMEOUT before rotating the queue on the
dedicated bulk endpoint.
This addresses an issue where a race could result in the endpoint
receiving data before it was reprogrammed resulting in a warning
about such data from musb_rx_reinit before it was thrown away.
The data thrown away was a valid packet that had been correctly
ACKed which meant the host and device got out of sync.
Signed-off-by: Andrew Goodbody <andrew.goodbody@cambrionix.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
[bwh: Backported to 3.2: adjust context, indentation]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit f3eec0cf upstream.

shared_fifo endpoints would only get a previous tx state cleared
out, the rx state was only cleared for non shared_fifo endpoints
Change this so that the rx state is cleared for all endpoints.
This addresses an issue that resulted in rx packets being dropped
silently.
Signed-off-by: Andrew Goodbody <andrew.goodbody@cambrionix.com>
Signed-off-by: Bin Liu <b-liu@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 0015f915 upstream.

This loop is supposed to set all the .num[] values to -1 but it's off by
one so it skips the first element and sets one element past the end of
the array.

I've cleaned up the loop a little as well.

Fixes: ddf8abd2 ('USB: f_fs: the FunctionFS driver')
Acked-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
[bwh: Backported to 3.2:
 - Adjust filename, context
 - Add 'i' for iteration but don't bother with 'eps_ptr' as the calculation is
   simpler here]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 3d56c25e upstream.

Ascend-to-parent logics in d_walk() depends on all encountered child
dentries not getting freed without an RCU delay.  Unfortunately, in
quite a few cases it is not true, with hard-to-hit oopsable race as
the result.

Fortunately, the fix is simiple; right now the rule is "if it ever
been hashed, freeing must be delayed" and changing it to "if it
ever had a parent, freeing must be delayed" closes that hole and
covers all cases the old rule used to cover.  Moreover, pipes and
sockets remain _not_ covered, so we do not introduce RCU delay in
the cases which are the reason for having that delay conditional
in the first place.
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
[bwh: Backported to 3.2:
 - Adjust context
 - Also set the flag in __d_materialise_dentry())]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 9c77679c upstream.

For newer versions of Syslinux, we need ldlinux.c32 in addition to
isolinux.bin to reside on the boot disk, so if the latter is found,
copy it, too, to the isoimage tree.
Signed-off-by: H. Peter Anvin <hpa@zytor.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit 8b78f260 upstream.

One of the debian buildd servers had this crash in the syslog without
any other information:

 Unaligned handler failed, ret = -2
 clock_adjtime (pid 22578): Unaligned data reference (code 28)
 CPU: 1 PID: 22578 Comm: clock_adjtime Tainted: G  E  4.5.0-2-parisc64-smp #1 Debian 4.5.4-1
 task: 000000007d9960f8 ti: 00000001bde7c000 task.ti: 00000001bde7c000

      YZrvWESTHLNXBCVMcbcbcbcbOGFRQPDI
 PSW: 00001000000001001111100000001111 Tainted: G            E
 r00-03  000000ff0804f80f 00000001bde7c2b0 00000000402d2be8 00000001bde7c2b0
 r04-07  00000000409e1fd0 00000000fa6f7fff 00000001bde7c148 00000000fa6f7fff
 r08-11  0000000000000000 00000000ffffffff 00000000fac9bb7b 000000000002b4d4
 r12-15  000000000015241c 000000000015242c 000000000000002d 00000000fac9bb7b
 r16-19  0000000000028800 0000000000000001 0000000000000070 00000001bde7c218
 r20-23  0000000000000000 00000001bde7c210 0000000000000002 0000000000000000
 r24-27  0000000000000000 0000000000000000 00000001bde7c148 00000000409e1fd0
 r28-31  0000000000000001 00000001bde7c320 00000001bde7c350 00000001bde7c218
 sr00-03  0000000001200000 0000000001200000 0000000000000000 0000000001200000
 sr04-07  0000000000000000 0000000000000000 0000000000000000 0000000000000000

 IASQ: 0000000000000000 0000000000000000 IAOQ: 00000000402d2e84 00000000402d2e88
  IIR: 0ca0d089    ISR: 0000000001200000  IOR: 00000000fa6f7fff
  CPU:        1   CR30: 00000001bde7c000 CR31: ffffffffffffffff
  ORIG_R28: 00000002369fe628
  IAOQ[0]: compat_get_timex+0x2dc/0x3c0
  IAOQ[1]: compat_get_timex+0x2e0/0x3c0
  RP(r2): compat_get_timex+0x40/0x3c0
 Backtrace:
  [<00000000402d4608>] compat_SyS_clock_adjtime+0x40/0xc0
  [<0000000040205024>] syscall_exit+0x0/0x14

This means the userspace program clock_adjtime called the clock_adjtime()
syscall and then crashed inside the compat_get_timex() function.
Syscalls should never crash programs, but instead return EFAULT.

The IIR register contains the executed instruction, which disassebles
into "ldw 0(sr3,r5),r9".
This load-word instruction is part of __get_user() which tried to read the word
at %r5/IOR (0xfa6f7fff). This means the unaligned handler jumped in.  The
unaligned handler is able to emulate all ldw instructions, but it fails if it
fails to read the source e.g. because of page fault.

The following program reproduces the problem:

#define _GNU_SOURCE
#include <unistd.h>
#include <sys/syscall.h>
#include <sys/mman.h>

int main(void) {
        /* allocate 8k */
        char *ptr = mmap(NULL, 2*4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
        /* free second half (upper 4k) and make it invalid. */
        munmap(ptr+4096, 4096);
        /* syscall where first int is unaligned and clobbers into invalid memory region */
        /* syscall should return EFAULT */
        return syscall(__NR_clock_adjtime, 0, ptr+4095);
}

To fix this issue we simply need to check if the faulting instruction address
is in the exception fixup table when the unaligned handler failed. If it
is, call the fixup routine instead of crashing.

While looking at the unaligned handler I found another issue as well: The
target register should not be modified if the handler was unsuccessful.
Signed-off-by: Helge Deller <deller@gmx.de>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>

commit d14bdb55 upstream.

MOV to DR6 or DR7 causes a #GP if an attempt is made to write a 1 to
any of bits 63:32.  However, this is not detected at KVM_SET_DEBUGREGS
time, and the next KVM_RUN oopses:

   general protection fault: 0000 [#1] SMP
   CPU: 2 PID: 14987 Comm: a.out Not tainted 4.4.9-300.fc23.x86_64 #1
   Hardware name: LENOVO 2325F51/2325F51, BIOS G2ET32WW (1.12 ) 05/30/2012
   [...]
   Call Trace:
    [<ffffffffa072c93d>] kvm_arch_vcpu_ioctl_run+0x141d/0x14e0 [kvm]
    [<ffffffffa071405d>] kvm_vcpu_ioctl+0x33d/0x620 [kvm]
    [<ffffffff81241648>] do_vfs_ioctl+0x298/0x480
    [<ffffffff812418a9>] SyS_ioctl+0x79/0x90
    [<ffffffff817a0f2e>] entry_SYSCALL_64_fastpath+0x12/0x71
   Code: 55 83 ff 07 48 89 e5 77 27 89 ff ff 24 fd 90 87 80 81 0f 23 fe 5d c3 0f 23 c6 5d c3 0f 23 ce 5d c3 0f 23 d6 5d c3 0f 23 de 5d c3 <0f> 23 f6 5d c3 0f 0b 66 66 66 66 66 2e 0f 1f 84 00 00 00 00 00
   RIP  [<ffffffff810639eb>] native_set_debugreg+0x2b/0x40
    RSP <ffff88005836bd50>

Testcase (beautified/reduced from syzkaller output):

    #include <unistd.h>
    #include <sys/syscall.h>
    #include <string.h>
    #include <stdint.h>
    #include <linux/kvm.h>
    #include <fcntl.h>
    #include <sys/ioctl.h>

    long r[8];

    int main()
    {
        struct kvm_debugregs dr = { 0 };

        r[2] = open("/dev/kvm", O_RDONLY);
        r[3] = ioctl(r[2], KVM_CREATE_VM, 0);
        r[4] = ioctl(r[3], KVM_CREATE_VCPU, 7);

        memcpy(&dr,
               "\x5d\x6a\x6b\xe8\x57\x3b\x4b\x7e\xcf\x0d\xa1\x72"
               "\xa3\x4a\x29\x0c\xfc\x6d\x44\x00\xa7\x52\xc7\xd8"
               "\x00\xdb\x89\x9d\x78\xb5\x54\x6b\x6b\x13\x1c\xe9"
               "\x5e\xd3\x0e\x40\x6f\xb4\x66\xf7\x5b\xe3\x36\xcb",
               48);
        r[7] = ioctl(r[4], KVM_SET_DEBUGREGS, &dr);
        r[6] = ioctl(r[4], KVM_RUN, 0);
    }
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Radim Krčmář <rkrcmar@redhat.com>
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>