linux-stable.git/drivers/md, branch v3.2.55

md/raid10: fix bug when raid10 recovery fails to recover a block.

2014-02-15T19:20:17+00:00

commit e8b849158508565e0cd6bc80061124afc5879160 upstream.

commit e875ecea266a543e643b19e44cf472f1412708f9
    md/raid10 record bad blocks as needed during recovery.

added code to the "cannot recover this block" path to record a bad
block rather than fail the whole recovery.
Unfortunately this new case was placed *after* r10bio was freed rather
than *before*, yet it still uses r10bio.
This is will crash with a null dereference.

So move the freeing of r10bio down where it is safe.

Fixes: e875ecea266a543e643b19e44cf472f1412708f9
Reported-by: Damian Nowak 
URL: https://bugzilla.kernel.org/show_bug.cgi?id=68181
Signed-off-by: NeilBrown 
Signed-off-by: Ben Hutchings

md/raid10: fix two bugs in handling of known-bad-blocks.

2014-02-15T19:20:16+00:00

commit b50c259e25d9260b9108dc0c2964c26e5ecbe1c1 upstream.

If we discover a bad block when reading we split the request and
potentially read some of it from a different device.

The code path of this has two bugs in RAID10.
1/ we get a spin_lock with _irq, but unlock without _irq!!
2/ The calculation of 'sectors_handled' is wrong, as can be clearly
   seen by comparison with raid1.c

This leads to at least 2 warnings and a probable crash is a RAID10
ever had known bad blocks.

Fixes: 856e08e23762dfb92ffc68fd0a8d228f9e152160
Reported-by: Damian Nowak 
URL: https://bugzilla.kernel.org/show_bug.cgi?id=68181
Signed-off-by: NeilBrown 
Signed-off-by: Ben Hutchings

md/raid5: Fix possible confusion when multiple write errors occur.

2014-02-15T19:20:16+00:00

commit 1cc03eb93245e63b0b7a7832165efdc52e25b4e6 upstream.

commit 5d8c71f9e5fbdd95650be00294d238e27a363b5c
    md: raid5 crash during degradation

Fixed a crash in an overly simplistic way which could leave
R5_WriteError or R5_MadeGood set in the stripe cache for devices
for which it is no longer relevant.
When those devices are removed and spares added the flags are still
set and can cause incorrect behaviour.

commit 14a75d3e07c784c004b4b44b34af996b8e4ac453
    md/raid5: preferentially read from replacement device if possible.

Fixed the same bug if a more effective way, so we can now revert
the original commit.

Reported-and-tested-by: Alexander Lyakas 
Fixes: 5d8c71f9e5fbdd95650be00294d238e27a363b5c
Signed-off-by: NeilBrown 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

dm bufio: initialize read-only module parameters

2014-01-03T04:33:30+00:00

commit 4cb57ab4a2e61978f3a9b7d4f53988f30d61c27f upstream.

Some module parameters in dm-bufio are read-only. These parameters
inform the user about memory consumption. They are not supposed to be
changed by the user.

However, despite being read-only, these parameters can be set on
modprobe or insmod command line, for example:
modprobe dm-bufio current_allocated_bytes=12345

The kernel doesn't expect that these variables can be non-zero at module
initialization and if the user sets them, it results in BUG.

This patch initializes the variables in the module init routine, so that
user-supplied values are ignored.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
Signed-off-by: Ben Hutchings

dm table: fail dm_table_create on dm_round_up overflow

2014-01-03T04:33:29+00:00

commit 5b2d06576c5410c10d95adfd5c4d8b24de861d87 upstream.

The dm_round_up function may overflow to zero.  In this case,
dm_table_create() must fail rather than go on to allocate an empty array
with alloc_targets().

This fixes a possible memory corruption that could be caused by passing
too large a number in "param->target_count".

Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
Signed-off-by: Ben Hutchings

dm snapshot: avoid snapshot space leak on crash

2014-01-03T04:33:29+00:00

commit 230c83afdd9cd384348475bea1e14b80b3b6b1b8 upstream.

There is a possible leak of snapshot space in case of crash.

The reason for space leaking is that chunks in the snapshot device are
allocated sequentially, but they are finished (and stored in the metadata)
out of order, depending on the order in which copying finished.

For example, supposed that the metadata contains the following records
SUPERBLOCK
METADATA (blocks 0 ... 250)
DATA 0
DATA 1
DATA 2
...
DATA 250

Now suppose that you allocate 10 new data blocks 251-260. Suppose that
copying of these blocks finish out of order (block 260 finished first
and the block 251 finished last). Now, the snapshot device looks like
this:
SUPERBLOCK
METADATA (blocks 0 ... 250, 260, 259, 258, 257, 256)
DATA 0
DATA 1
DATA 2
...
DATA 250
DATA 251
DATA 252
DATA 253
DATA 254
DATA 255
METADATA (blocks 255, 254, 253, 252, 251)
DATA 256
DATA 257
DATA 258
DATA 259
DATA 260

Now, if the machine crashes after writing the first metadata block but
before writing the second metadata block, the space for areas DATA 250-255
is leaked, it contains no valid data and it will never be used in the
future.

This patch makes dm-snapshot complete exceptions in the same order they
were allocated, thus fixing this bug.

Note: when backporting this patch to the stable kernel, change the version
field in the following way:
* if version in the stable kernel is {1, 11, 1}, change it to {1, 12, 0}
* if version in the stable kernel is {1, 10, 0} or {1, 10, 1}, change it
  to {1, 10, 2}
Userspace reads the version to determine if the bug was fixed, so the
version change is needed.

Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
Signed-off-by: Ben Hutchings

dm delay: fix a possible deadlock due to shared workqueue

2014-01-03T04:33:22+00:00

commit 718822c1c112dc99e0c72c8968ee1db9d9d910f0 upstream.

The dm-delay target uses a shared workqueue for multiple instances.  This
can cause deadlock if two or more dm-delay targets are stacked on the top
of each other.

This patch changes dm-delay to use a per-instance workqueue.


Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
Signed-off-by: Ben Hutchings

dm mpath: fix race condition between multipath_dtr and pg_init_done

2014-01-03T04:33:16+00:00

commit 954a73d5d3073df2231820c718fdd2f18b0fe4c9 upstream.

Whenever multipath_dtr() is happening we must prevent queueing any
further path activation work.  Implement this by adding a new
'pg_init_disabled' flag to the multipath structure that denotes future
path activation work should be skipped if it is set.  By disabling
pg_init and then re-enabling in flush_multipath_work() we also avoid the
potential for pg_init to be initiated while suspending an mpath device.

Without this patch a race condition exists that may result in a kernel
panic:

1) If after pg_init_done() decrements pg_init_in_progress to 0, a call
   to wait_for_pg_init_completion() assumes there are no more pending path
   management commands.
2) If pg_init_required is set by pg_init_done(), due to retryable
   mode_select errors, then process_queued_ios() will again queue the
   path activation work.
3) If free_multipath() completes before activate_path() work is called a
   NULL pointer dereference like the following can be seen when
   accessing members of the recently destructed multipath:

BUG: unable to handle kernel NULL pointer dereference at 0000000000000090
RIP: 0010:[]  [] activate_path+0x1b/0x30 [dm_multipath]
[] worker_thread+0x170/0x2a0
[] ? autoremove_wake_function+0x0/0x40

[switch to disabling pg_init in flush_multipath_work & header edits by Mike Snitzer]
Signed-off-by: Shiva Krishna Merla 
Reviewed-by: Krishnasamy Somasundaram 
Tested-by: Speagle Andy 
Acked-by: Junichi Nomura 
Signed-off-by: Mike Snitzer 
[bwh: Backported to 3.2:
 - Adjust context
 - Bump version to 1.3.2 not 1.6.0]
Signed-off-by: Ben Hutchings

dm: allocate buffer for messages with small number of arguments using GFP_NOIO

2014-01-03T04:33:16+00:00

commit f36afb3957353d2529cb2b00f78fdccd14fc5e9c upstream.

dm-mpath and dm-thin must process messages even if some device is
suspended, so we allocate argv buffer with GFP_NOIO. These messages have
a small fixed number of arguments.

On the other hand, dm-switch needs to process bulk data using messages
so excessive use of GFP_NOIO could cause trouble.

The patch also lowers the default number of arguments from 64 to 8, so
that there is smaller load on GFP_NOIO allocations.

Signed-off-by: Mikulas Patocka 
Acked-by: Alasdair G Kergon 
Signed-off-by: Mike Snitzer 
Signed-off-by: Ben Hutchings

dm snapshot: fix data corruption

2013-11-28T14:02:04+00:00

commit e9c6a182649f4259db704ae15a91ac820e63b0ca upstream.

This patch fixes a particular type of data corruption that has been
encountered when loading a snapshot's metadata from disk.

When we allocate a new chunk in persistent_prepare, we increment
ps->next_free and we make sure that it doesn't point to a metadata area
by further incrementing it if necessary.

When we load metadata from disk on device activation, ps->next_free is
positioned after the last used data chunk. However, if this last used
data chunk is followed by a metadata area, ps->next_free is positioned
erroneously to the metadata area. A newly-allocated chunk is placed at
the same location as the metadata area, resulting in data or metadata
corruption.

This patch changes the code so that ps->next_free skips the metadata
area when metadata are loaded in function read_exceptions.

The patch also moves a piece of code from persistent_prepare_exception
to a separate function skip_metadata to avoid code duplication.

CVE-2013-4299

Signed-off-by: Mikulas Patocka 
Cc: Mike Snitzer 
Signed-off-by: Alasdair G Kergon 
Signed-off-by: Ben Hutchings