Unfortunately key_string may theoretically contain whitespace even after
it's processed by dm_split_args(). The reason for this is DM core
supports escaping of almost all chars including any whitespace.
If userspace passes a key to the kernel in format ":32:logon:my_prefix:my\ key"
dm-crypt will look up key "my_prefix:my key" in kernel keyring service.
So far everything's fine.
Unfortunately if userspace later calls DM_TABLE_STATUS ioctl, it will not
receive back expected ":32:logon:my_prefix:my\ key" but the unescaped version
instead. Also userpace (most notably cryptsetup) is not ready to parse
single target argument containing (even escaped) whitespace chars and any
whitespace is simply taken as delimiter of another argument.
This effect is mitigated by the fact libdevmapper curently performs
double escaping of '\' char. Any user input in format "x\ x" is
transformed into "x\\ x" before being passed to the kernel. Nonetheless
dm-crypt may be used without libdevmapper. Therefore the near-term
solution to this is to reject any key string containing whitespace.
Signed-off-by: Ondrej Kozina <okozina@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
If no block was allocated or freed, sm_ll_mutate() wasn't setting
*ev, leaving the variable unitialized. sm_ll_insert(),
sm_disk_inc_block(), and sm_disk_new_block() all check ev to see
if there was an allocation event in sm_ll_mutate(), possibly
reading unitialized data.
If no allocation event occured, sm_ll_mutate() should set *ev
to SM_NONE.
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
When metadata_ll_init_index() is called by sm_ll_new_metadata(),
ll->mi_le hasn't been initialized yet. So, when
metadata_ll_init_index() copies the contents of ll->mi_le into the
newly allocated bitmap_root, it is just copying garbage. ll->mi_le
will be allocated later in sm_ll_extend() and copied into the
bitmap_root, in sm_ll_commit().
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
In dm_sm_metadata_create() we temporarily change the dm_space_map
operations from 'ops' (whose .destroy function deallocates the
sm_metadata) to 'bootstrap_ops' (whose .destroy function doesn't).
If dm_sm_metadata_create() fails in sm_ll_new_metadata() or
sm_ll_extend(), it exits back to dm_tm_create_internal(), which calls
dm_sm_destroy() with the intention of freeing the sm_metadata, but it
doesn't (because the dm_space_map operations is still set to
'bootstrap_ops').
Fix this by setting the dm_space_map operations back to 'ops' if
dm_sm_metadata_create() fails when it is set to 'bootstrap_ops'.
Signed-off-by: Benjamin Marzinski <bmarzins@redhat.com>
Acked-by: Joe Thornber <ejt@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Cc: stable@vger.kernel.org
Commit ecbfb9f118 ("dm raid: add raid level takeover support") moved the
configure_discard_support() call from raid_ctr() to raid_preresume().
Enabling/disabling discard _must_ happen during table load (through the
.ctr hook). Fix this regression by moving the
configure_discard_support() call back to raid_ctr().
Fixes: ecbfb9f118 ("dm raid: add raid level takeover support")
Cc: stable@vger.kernel.org # 4.8+
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Remove CTR_FLAG_MAX_WRITE_BEHIND from raid4/5/6's valid ctr flags.
Only the md raid1 personality supports setting a maximum number
of "write behind" write IOs on any legs set to "write mostly".
"write mostly" enhances throughput with slow links/disks.
Technically the "write behind" value is a write intent bitmap
property only being respected by the raid1 personality. It allows a
maximum number of "write behind" writes to any "write mostly" raid1
mirror legs to be delayed and avoids reads from such legs.
No other MD personalities supported via dm-raid make use of "write
behind", thus setting this property is superfluous; it wouldn't cause
harm but it is correct to reject it.
Signed-off-by: Heinz Mauelshagen <heinzm@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Let the requested m->hw_handler_params be used if the attached hardware
handler is the same handler as requested with m->hw_handler_name.
Signed-off-by: tang.junhui <tang.junhui@zte.com.cn>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
The kernel key service is a generic way to store keys for the use of
other subsystems. Currently there is no way to use kernel keys in dm-crypt.
This patch aims to fix that. Instead of key userspace may pass a key
description with preceding ':'. So message that constructs encryption
mapping now looks like this:
<cipher> [<key>|:<key_string>] <iv_offset> <dev_path> <start> [<#opt_params> <opt_params>]
where <key_string> is in format: <key_size>:<key_type>:<key_description>
Currently we only support two elementary key types: 'user' and 'logon'.
Keys may be loaded in dm-crypt either via <key_string> or using
classical method and pass the key in hex representation directly.
dm-crypt device initialised with a key passed in hex representation may be
replaced with key passed in key_string format and vice versa.
(Based on original work by Andrey Ryabinin)
Signed-off-by: Ondrej Kozina <okozina@redhat.com>
Reviewed-by: David Howells <dhowells@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Subtracting sizes is a fragile approach because the result is only
correct if the compiler has not added any padding at the end of the
structure. Hence use offsetof() instead of size subtraction. An
additional advantage of offsetof() is that it makes the intent more
clear.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Use a single statement to declare and initialize 'use_blk_mq' instead
of two statements.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
After QUEUE_FLAG_DYING has been set any code that is waiting in
get_request() should be woken up. But to get this behaviour
blk_set_queue_dying() must be used instead of only setting
QUEUE_FLAG_DYING.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
If the first allocation attempt using GFP_NOWAIT fails, drop the lock
and retry using GFP_NOIO allocation (lock is dropped because the
allocation can take some time).
Note that we won't do GFP_NOIO allocation when we loop for the second
time, because the lock shouldn't be dropped between __wait_for_free_buffer
and __get_unclaimed_buffer.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
dm_bufio_shrink_count() is called from do_shrink_slab to find out how many
freeable objects are there. The reported value doesn't have to be precise,
so we don't need to take the dm-bufio lock.
Suggested-by: David Rientjes <rientjes@google.com>
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
We've seen in-field reports showing _lots_ (18 in one case, 41 in
another) of tasks all sitting there blocked on:
mutex_lock+0x4c/0x68
dm_bufio_shrink_count+0x38/0x78
shrink_slab.part.54.constprop.65+0x100/0x464
shrink_zone+0xa8/0x198
In the two cases analyzed, we see one task that looks like this:
Workqueue: kverityd verity_prefetch_io
__switch_to+0x9c/0xa8
__schedule+0x440/0x6d8
schedule+0x94/0xb4
schedule_timeout+0x204/0x27c
schedule_timeout_uninterruptible+0x44/0x50
wait_iff_congested+0x9c/0x1f0
shrink_inactive_list+0x3a0/0x4cc
shrink_lruvec+0x418/0x5cc
shrink_zone+0x88/0x198
try_to_free_pages+0x51c/0x588
__alloc_pages_nodemask+0x648/0xa88
__get_free_pages+0x34/0x7c
alloc_buffer+0xa4/0x144
__bufio_new+0x84/0x278
dm_bufio_prefetch+0x9c/0x154
verity_prefetch_io+0xe8/0x10c
process_one_work+0x240/0x424
worker_thread+0x2fc/0x424
kthread+0x10c/0x114
...and that looks to be the one holding the mutex.
The problem has been reproduced on fairly easily:
0. Be running Chrome OS w/ verity enabled on the root filesystem
1. Pick test patch: http://crosreview.com/412360
2. Install launchBalloons.sh and balloon.arm from
http://crbug.com/468342
...that's just a memory stress test app.
3. On a 4GB rk3399 machine, run
nice ./launchBalloons.sh 4 900 100000
...that tries to eat 4 * 900 MB of memory and keep accessing.
4. Login to the Chrome web browser and restore many tabs
With that, I've seen printouts like:
DOUG: long bufio 90758 ms
...and stack trace always show's we're in dm_bufio_prefetch().
The problem is that we try to allocate memory with GFP_NOIO while
we're holding the dm_bufio lock. Instead we should be using
GFP_NOWAIT. Using GFP_NOIO can cause us to sleep while holding the
lock and that causes the above problems.
The current behavior explained by David Rientjes:
It will still try reclaim initially because __GFP_WAIT (or
__GFP_KSWAPD_RECLAIM) is set by GFP_NOIO. This is the cause of
contention on dm_bufio_lock() that the thread holds. You want to
pass GFP_NOWAIT instead of GFP_NOIO to alloc_buffer() when holding a
mutex that can be contended by a concurrent slab shrinker (if
count_objects didn't use a trylock, this pattern would trivially
deadlock).
This change significantly increases responsiveness of the system while
in this state. It makes a real difference because it unblocks kswapd.
In the bug report analyzed, kswapd was hung:
kswapd0 D ffffffc000204fd8 0 72 2 0x00000000
Call trace:
[<ffffffc000204fd8>] __switch_to+0x9c/0xa8
[<ffffffc00090b794>] __schedule+0x440/0x6d8
[<ffffffc00090bac0>] schedule+0x94/0xb4
[<ffffffc00090be44>] schedule_preempt_disabled+0x28/0x44
[<ffffffc00090d900>] __mutex_lock_slowpath+0x120/0x1ac
[<ffffffc00090d9d8>] mutex_lock+0x4c/0x68
[<ffffffc000708e7c>] dm_bufio_shrink_count+0x38/0x78
[<ffffffc00030b268>] shrink_slab.part.54.constprop.65+0x100/0x464
[<ffffffc00030dbd8>] shrink_zone+0xa8/0x198
[<ffffffc00030e578>] balance_pgdat+0x328/0x508
[<ffffffc00030eb7c>] kswapd+0x424/0x51c
[<ffffffc00023f06c>] kthread+0x10c/0x114
[<ffffffc000203dd0>] ret_from_fork+0x10/0x40
By unblocking kswapd memory pressure should be reduced.
Suggested-by: David Rientjes <rientjes@google.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Use a single loop instead of two loops to determine whether or not
all_blk_mq has to be set.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
When dm_table_set_type() is used by a target to establish a DM table's
type (e.g. DM_TYPE_MQ_REQUEST_BASED in the case of DM multipath) the
DM core must go on to verify that the devices in the table are
compatible with the established type.
Fixes: e83068a5 ("dm mpath: add optional "queue_mode" feature")
Cc: stable@vger.kernel.org # 4.8+
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
An earlier DM multipath table could have been build ontop of underlying
devices that were all using blk-mq. In that case, if that active
multipath table is replaced with an empty DM multipath table (that
reflects all paths have failed) then it is important that the
'all_blk_mq' state of the active table is transfered to the new empty DM
table. Otherwise dm-rq.c:dm_old_prep_tio() will incorrectly clone a
request that isn't needed by the DM multipath target when it is to issue
IO to an underlying blk-mq device.
Fixes: e83068a5 ("dm mpath: add optional "queue_mode" feature")
Cc: stable@vger.kernel.org # 4.8+
Reported-by: Bart Van Assche <bart.vanassche@sandisk.com>
Tested-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Purely cleanup, avoids potential for strange coding bugs. But in
reality if __multipath_map() fails the caller has no business looking at
*__clone.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
This avoids the potential for invalid memory access, if/when there are
no priority groups, in response to invalid arguments being sent by the
user via DM message (e.g. "switch_group", "disable_group" or
"enable_group").
Signed-off-by: tang.junhui <tang.junhui@zte.com.cn>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Avoids false positive of no hardware handler being specified (which is
implied by a NULL m->hw_handler_name).
Signed-off-by: tang.junhui <tang.junhui@zte.com.cn>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
Fix to return error code -EINVAL instead of 0, as is done elsewhere in
this function.
Fixes: e80d1c805a ("dm: do not override error code returned from dm_get_device()")
Cc: stable@vger.kernel.org # 4.3+
Signed-off-by: Wei Yongjun <weiyj.lk@gmail.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
