linux-stable.git/drivers/md/dm-table.c, branch linux-3.16.y

dm table: fix invalid memory accesses with too high sector number

2019-11-22T15:57:19+00:00

commit 1cfd5d3399e87167b7f9157ef99daa0e959f395d upstream.

If the sector number is too high, dm_table_find_target() should return a
pointer to a zeroed dm_target structure (the caller should test it with
dm_target_is_valid).

However, for some table sizes, the code in dm_table_find_target() that
performs btree lookup will access out of bound memory structures.

Fix this bug by testing the sector number at the beginning of
dm_table_find_target(). Also, add an "inline" keyword to the function
dm_table_get_size() because this is a hot path.

Fixes: 512875bd9661 ("dm: table detect io beyond device")
Reported-by: Zhang Tao 
Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
Signed-off-by: Ben Hutchings

dm table: propagate BDI_CAP_STABLE_WRITES to fix sporadic checksum errors

2019-08-13T11:38:58+00:00

commit eb40c0acdc342b815d4d03ae6abb09e80c0f2988 upstream.

Some devices don't use blk_integrity but still want stable pages
because they do their own checksumming.  Examples include rbd and iSCSI
when data digests are negotiated.  Stacking DM (and thus LVM) on top of
these devices results in sporadic checksum errors.

Set BDI_CAP_STABLE_WRITES if any underlying device has it set.

Signed-off-by: Ilya Dryomov 
Signed-off-by: Mike Snitzer 
[bwh: Backported to 3.16: request_queue::backing_dev_info is a struct
 not a pointer]
Signed-off-by: Ben Hutchings

dm: discard support requires all targets in a table support discards

2018-02-13T18:42:23+00:00

commit 8a74d29d541cd86569139c6f3f44b2d210458071 upstream.

A DM device with a mix of discard capabilities (due to some underlying
devices not having discard support) _should_ just return -EOPNOTSUPP for
the region of the device that doesn't support discards (even if only by
way of the underlying driver formally not supporting discards).  BUT,
that does ask the underlying driver to handle something that it never
advertised support for.  In doing so we're exposing users to the
potential for a underlying disk driver hanging if/when a discard is
issued a the device that is incapable and never claimed to support
discards.

Fix this by requiring that each DM target in a DM table provide discard
support as a prereq for a DM device to advertise support for discards.

This may cause some configurations that were happily supporting discards
(even in the face of a mix of discard support) to stop supporting
discards -- but the risk of users hitting driver hangs, and forced
reboots, outweighs supporting those fringe mixed discard
configurations.

Signed-off-by: Mike Snitzer 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

dm table: fix missing dm_put_target_type() in dm_table_add_target()

2017-02-23T03:54:20+00:00

commit dafa724bf582181d9a7d54f5cb4ca0bf8ef29269 upstream.

dm_get_target_type() was previously called so any error returned from
dm_table_add_target() must first call dm_put_target_type().  Otherwise
the DM target module's reference count will leak and the associated
kernel module will be unable to be removed.

Also, leverage the fact that r is already -EINVAL and remove an extra
newline.

Fixes: 36a0456 ("dm table: add immutable feature")
Fixes: cc6cbe1 ("dm table: add always writeable feature")
Fixes: 3791e2f ("dm table: add singleton feature")
Signed-off-by: tang.junhui 
Signed-off-by: Mike Snitzer 
[bwh: Backported to 3.16: adjuat context]
Signed-off-by: Ben Hutchings

dm table: propagate QUEUE_FLAG_NO_SG_MERGE

2014-09-17T16:22:21+00:00

commit 200612ec33e555a356eebc717630b866ae2b694f upstream.

Commit 05f1dd5 ("block: add queue flag for disabling SG merging")
introduced a new queue flag: QUEUE_FLAG_NO_SG_MERGE.  This gets set by
default in blk_mq_init_queue for mq-enabled devices.  The effect of
the flag is to bypass the SG segment merging.  Instead, the
bio->bi_vcnt is used as the number of hardware segments.

With a device mapper target on top of a device with
QUEUE_FLAG_NO_SG_MERGE set, we can end up sending down more segments
than a driver is prepared to handle.  I ran into this when backporting
the virtio_blk mq support.  It triggerred this BUG_ON, in
virtio_queue_rq:

        BUG_ON(req->nr_phys_segments + 2 > vblk->sg_elems);

The queue's max is set here:
        blk_queue_max_segments(q, vblk->sg_elems-2);

Basically, what happens is that a bio is built up for the dm device
(which does not have the QUEUE_FLAG_NO_SG_MERGE flag set) using
bio_add_page.  That path will call into __blk_recalc_rq_segments, so
what you end up with is bi_phys_segments being much smaller than bi_vcnt
(and bi_vcnt grows beyond the maximum sg elements).  Then, when the bio
is submitted, it gets cloned.  When the cloned bio is submitted, it will
end up in blk_recount_segments, here:

        if (test_bit(QUEUE_FLAG_NO_SG_MERGE, &q->queue_flags))
                bio->bi_phys_segments = bio->bi_vcnt;

and now we've set bio->bi_phys_segments to a number that is beyond what
was registered as queue_max_segments by the driver.

The right way to fix this is to propagate the queue flag up the stack.

The rules for propagating the flag are simple:
- if the flag is set for any underlying device, it must be set for the
  upper device
- consequently, if the flag is not set for any underlying device, it
  should not be set for the upper device.

Signed-off-by: Jeff Moyer 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm: remove symbol export for dm_set_device_limits

2014-06-04T13:46:34+00:00

There is no need for code other than DM core to use dm_set_device_limits
so remove its EXPORT_SYMBOL_GPL.  Also, cleanup a couple whitespace nits.

Signed-off-by: Mike Snitzer

dm table: add dm_table_run_md_queue_async

2014-03-27T20:56:24+00:00

Introduce dm_table_run_md_queue_async() to run the request_queue of the
mapped_device associated with a request-based DM table.

Also add dm_md_get_queue() wrapper to extract the request_queue from a
mapped_device.

Signed-off-by: Mike Snitzer 
Signed-off-by: Hannes Reinecke 
Reviewed-by: Jun'ichi Nomura

dm: make dm_table_alloc_md_mempools static

2014-03-27T20:56:23+00:00

Make the function dm_table_alloc_md_mempools static because it is not
called from another file.

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

dm table: remove unused buggy code that extends the targets array

2014-01-07T15:11:44+00:00

A device mapper table is allocated in the following way:
* The function dm_table_create is called, it gets the number of targets
  as an argument -- it allocates a targets array accordingly.
* For each target, we call dm_table_add_target.

If we add more targets than were specified in dm_table_create, the
function dm_table_add_target reallocates the targets array.  However,
this reallocation code is wrong - it moves the targets array to a new
location, while some target constructors hold pointers to the array in
the old location.

The following DM target drivers save the pointer to the target
structure, so they corrupt memory if the target array is moved:
multipath, raid, mirror, snapshot, stripe, switch, thin, verity.

Under normal circumstances, the reallocation function is not called
(because dm_table_create is called with the correct number of targets),
so the buggy reallocation code is not used.

Prior to the fix "dm table: fail dm_table_create on dm_round_up
overflow", the reallocation code could only be used in case the user
specifies too large a value in param->target_count, such as 0xffffffff.

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

dm table: fail dm_table_create on dm_round_up overflow

2013-12-10T21:34:27+00:00

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 
Cc: stable@vger.kernel.org