linux-stable.git/drivers/md, branch v3.16.71

md: Fix failed allocation of md_register_thread

2019-07-09T21:04:16+00:00

commit e406f12dde1a8375d77ea02d91f313fb1a9c6aec upstream.

mddev->sync_thread can be set to NULL on kzalloc failure downstream.
The patch checks for such a scenario and frees allocated resources.

Committer node:

Added similar fix to raid5.c, as suggested by Guoqing.

Acked-by: Guoqing Jiang 
Signed-off-by: Aditya Pakki 
Signed-off-by: Song Liu 
Signed-off-by: Ben Hutchings

It's wrong to add len to sector_nr in raid10 reshape twice

2019-07-09T21:04:16+00:00

commit b761dcf1217760a42f7897c31dcb649f59b2333e upstream.

In reshape_request it already adds len to sector_nr already. It's wrong to add len to
sector_nr again after adding pages to bio. If there is bad block it can't copy one chunk
at a time, it needs to goto read_more. Now the sector_nr is wrong. It can cause data
corruption.

Signed-off-by: Xiao Ni 
Signed-off-by: Song Liu 
Signed-off-by: Ben Hutchings

bcache: treat stale && dirty keys as bad keys

2019-07-09T21:03:57+00:00

commit 58ac323084ebf44f8470eeb8b82660f9d0ee3689 upstream.

Stale && dirty keys can be produced in the follow way:
After writeback in write_dirty_finish(), dirty keys k1 will
replace by clean keys k2
==>ret = bch_btree_insert(dc->disk.c, &keys, NULL, &w->key);
==>btree_insert_fn(struct btree_op *b_op, struct btree *b)
==>static int bch_btree_insert_node(struct btree *b,
       struct btree_op *op,
       struct keylist *insert_keys,
       atomic_t *journal_ref,
Then two steps:
A) update k1 to k2 in btree node memory;
   bch_btree_insert_keys(b, op, insert_keys, replace_key)
B) Write the bset(contains k2) to cache disk by a 30s delay work
   bch_btree_leaf_dirty(b, journal_ref).
But before the 30s delay work write the bset to cache device,
these things happened:
A) GC works, and reclaim the bucket k2 point to;
B) Allocator works, and invalidate the bucket k2 point to,
   and increase the gen of the bucket, and place it into free_inc
   fifo;
C) Until now, the 30s delay work still does not finish work,
   so in the disk, the key still is k1, it is dirty and stale
   (its gen is smaller than the gen of the bucket). and then the
   machine power off suddenly happens;
D) When the machine power on again, after the btree reconstruction,
   the stale dirty key appear.

In bch_extent_bad(), when expensive_debug_checks is off, it would
treat the dirty key as good even it is stale keys, and it would
cause bellow probelms:
A) In read_dirty() it would cause machine crash:
   BUG_ON(ptr_stale(dc->disk.c, &w->key, 0));
B) It could be worse when reads hits stale dirty keys, it would
   read old incorrect data.

This patch tolerate the existence of these stale && dirty keys,
and treat them as bad key in bch_extent_bad().

(Coly Li: fix indent which was modified by sender's email client)

Signed-off-by: Tang Junhui 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe 
[bwh: Backported to 3.16: adjust context]
Signed-off-by: Ben Hutchings

bcache: never writeback a discard operation

2019-07-09T21:03:56+00:00

commit 9951379b0ca88c95876ad9778b9099e19a95d566 upstream.

Some users see panics like the following when performing fstrim on a
bcached volume:

[  529.803060] BUG: unable to handle kernel NULL pointer dereference at 0000000000000008
[  530.183928] #PF error: [normal kernel read fault]
[  530.412392] PGD 8000001f42163067 P4D 8000001f42163067 PUD 1f42168067 PMD 0
[  530.750887] Oops: 0000 [#1] SMP PTI
[  530.920869] CPU: 10 PID: 4167 Comm: fstrim Kdump: loaded Not tainted 5.0.0-rc1+ #3
[  531.290204] Hardware name: HP ProLiant DL360 Gen9/ProLiant DL360 Gen9, BIOS P89 12/27/2015
[  531.693137] RIP: 0010:blk_queue_split+0x148/0x620
[  531.922205] Code: 60 38 89 55 a0 45 31 db 45 31 f6 45 31 c9 31 ff 89 4d 98 85 db 0f 84 7f 04 00 00 44 8b 6d 98 4c 89 ee 48 c1 e6 04 49 03 70 78 <8b> 46 08 44 8b 56 0c 48
8b 16 44 29 e0 39 d8 48 89 55 a8 0f 47 c3
[  532.838634] RSP: 0018:ffffb9b708df39b0 EFLAGS: 00010246
[  533.093571] RAX: 00000000ffffffff RBX: 0000000000046000 RCX: 0000000000000000
[  533.441865] RDX: 0000000000000200 RSI: 0000000000000000 RDI: 0000000000000000
[  533.789922] RBP: ffffb9b708df3a48 R08: ffff940d3b3fdd20 R09: 0000000000000000
[  534.137512] R10: ffffb9b708df3958 R11: 0000000000000000 R12: 0000000000000000
[  534.485329] R13: 0000000000000000 R14: 0000000000000000 R15: ffff940d39212020
[  534.833319] FS:  00007efec26e3840(0000) GS:ffff940d1f480000(0000) knlGS:0000000000000000
[  535.224098] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[  535.504318] CR2: 0000000000000008 CR3: 0000001f4e256004 CR4: 00000000001606e0
[  535.851759] Call Trace:
[  535.970308]  ? mempool_alloc_slab+0x15/0x20
[  536.174152]  ? bch_data_insert+0x42/0xd0 [bcache]
[  536.403399]  blk_mq_make_request+0x97/0x4f0
[  536.607036]  generic_make_request+0x1e2/0x410
[  536.819164]  submit_bio+0x73/0x150
[  536.980168]  ? submit_bio+0x73/0x150
[  537.149731]  ? bio_associate_blkg_from_css+0x3b/0x60
[  537.391595]  ? _cond_resched+0x1a/0x50
[  537.573774]  submit_bio_wait+0x59/0x90
[  537.756105]  blkdev_issue_discard+0x80/0xd0
[  537.959590]  ext4_trim_fs+0x4a9/0x9e0
[  538.137636]  ? ext4_trim_fs+0x4a9/0x9e0
[  538.324087]  ext4_ioctl+0xea4/0x1530
[  538.497712]  ? _copy_to_user+0x2a/0x40
[  538.679632]  do_vfs_ioctl+0xa6/0x600
[  538.853127]  ? __do_sys_newfstat+0x44/0x70
[  539.051951]  ksys_ioctl+0x6d/0x80
[  539.212785]  __x64_sys_ioctl+0x1a/0x20
[  539.394918]  do_syscall_64+0x5a/0x110
[  539.568674]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

We have observed it where both:
1) LVM/devmapper is involved (bcache backing device is LVM volume) and
2) writeback cache is involved (bcache cache_mode is writeback)

On one machine, we can reliably reproduce it with:

 # echo writeback > /sys/block/bcache0/bcache/cache_mode
   (not sure whether above line is required)
 # mount /dev/bcache0 /test
 # for i in {0..10}; do
	file="$(mktemp /test/zero.XXX)"
	dd if=/dev/zero of="$file" bs=1M count=256
	sync
	rm $file
    done
  # fstrim -v /test

Observing this with tracepoints on, we see the following writes:

fstrim-18019 [022] .... 91107.302026: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0  DS 4260112 + 196352 hit 0 bypass 1
fstrim-18019 [022] .... 91107.302050: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0  DS 4456464 + 262144 hit 0 bypass 1
fstrim-18019 [022] .... 91107.302075: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0  DS 4718608 + 81920 hit 0 bypass 1
fstrim-18019 [022] .... 91107.302094: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0  DS 5324816 + 180224 hit 0 bypass 1
fstrim-18019 [022] .... 91107.302121: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0  DS 5505040 + 262144 hit 0 bypass 1
fstrim-18019 [022] .... 91107.302145: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0  DS 5767184 + 81920 hit 0 bypass 1
fstrim-18019 [022] .... 91107.308777: bcache_write: 73f95583-561c-408f-a93a-4cbd2498f5c8 inode 0  DS 6373392 + 180224 hit 1 bypass 0


Note the final one has different hit/bypass flags.

This is because in should_writeback(), we were hitting a case where
the partial stripe condition was returning true and so
should_writeback() was returning true early.

If that hadn't been the case, it would have hit the would_skip test, and
as would_skip == s->iop.bypass == true, should_writeback() would have
returned false.

Looking at the git history from 'commit 72c270612bd3 ("bcache: Write out
full stripes")', it looks like the idea was to optimise for raid5/6:

       * If a stripe is already dirty, force writes to that stripe to
	 writeback mode - to help build up full stripes of dirty data

To fix this issue, make sure that should_writeback() on a discard op
never returns true.

More details of debugging:
https://www.spinics.net/lists/linux-bcache/msg06996.html

Previous reports:
 - https://bugzilla.kernel.org/show_bug.cgi?id=201051
 - https://bugzilla.kernel.org/show_bug.cgi?id=196103
 - https://www.spinics.net/lists/linux-bcache/msg06885.html

(Coly Li: minor modification to follow maximum 75 chars per line rule)

Cc: Kent Overstreet 
Fixes: 72c270612bd3 ("bcache: Write out full stripes")
Signed-off-by: Daniel Axtens 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe 
[bwh: Backported to 3.16: check REQ_DISCARD flag instead of calling bio_op()]
Signed-off-by: Ben Hutchings

dm thin: fix bug where bio that overwrites thin block ignores FUA

2019-05-02T20:41:55+00:00

commit 4ae280b4ee3463fa57bbe6eede26b97daff8a0f1 upstream.

When provisioning a new data block for a virtual block, either because
the block was previously unallocated or because we are breaking sharing,
if the whole block of data is being overwritten the bio that triggered
the provisioning is issued immediately, skipping copying or zeroing of
the data block.

When this bio completes the new mapping is inserted in to the pool's
metadata by process_prepared_mapping(), where the bio completion is
signaled to the upper layers.

This completion is signaled without first committing the metadata.  If
the bio in question has the REQ_FUA flag set and the system crashes
right after its completion and before the next metadata commit, then the
write is lost despite the REQ_FUA flag requiring that I/O completion for
this request must only be signaled after the data has been committed to
non-volatile storage.

Fix this by deferring the completion of overwrite bios, with the REQ_FUA
flag set, until after the metadata has been committed.

Signed-off-by: Nikos Tsironis 
Acked-by: Joe Thornber 
Acked-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
[bwh: Backported to 3.16:
 - bio_endio() takes an error parameter
 - Adjust context]
Signed-off-by: Ben Hutchings

dm ioctl: harden copy_params()'s copy_from_user() from malicious users

2019-02-11T17:53:38+00:00

commit 800a7340ab7dd667edf95e74d8e4f23a17e87076 upstream.

In copy_params(), the struct 'dm_ioctl' is first copied from the user
space buffer 'user' to 'param_kernel' and the field 'data_size' is
checked against 'minimum_data_size' (size of 'struct dm_ioctl' payload
up to its 'data' member).  If the check fails, an error code EINVAL will be
returned.  Otherwise, param_kernel->data_size is used to do a second copy,
which copies from the same user-space buffer to 'dmi'.  After the second
copy, only 'dmi->data_size' is checked against 'param_kernel->data_size'.
Given that the buffer 'user' resides in the user space, a malicious
user-space process can race to change the content in the buffer between
the two copies.  This way, the attacker can inject inconsistent data
into 'dmi' (versus previously validated 'param_kernel').

Fix redundant copying of 'minimum_data_size' from user-space buffer by
using the first copy stored in 'param_kernel'.  Also remove the
'data_size' check after the second copy because it is now unnecessary.

Signed-off-by: Wenwen Wang 
Signed-off-by: Mike Snitzer 
Signed-off-by: Ben Hutchings

bcache: fix miss key refill->end in writeback

2019-02-11T17:53:29+00:00

commit 2d6cb6edd2c7fb4f40998895bda45006281b1ac5 upstream.

refill->end record the last key of writeback, for example, at the first
time, keys (1,128K) to (1,1024K) are flush to the backend device, but
the end key (1,1024K) is not included, since the bellow code:
	if (bkey_cmp(k, refill->end) >= 0) {
		ret = MAP_DONE;
		goto out;
	}
And in the next time when we refill writeback keybuf again, we searched
key start from (1,1024K), and got a key bigger than it, so the key
(1,1024K) missed.
This patch modify the above code, and let the end key to be included to
the writeback key buffer.

Signed-off-by: Tang Junhui 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe 
Signed-off-by: Ben Hutchings

bcache: fix wrong cache_misses statistics

2019-02-11T17:53:29+00:00

commit c157313791a999646901b3e3c6888514ebc36d62 upstream.

Currently, Cache missed IOs are identified by s->cache_miss, but actually,
there are many situations that missed IOs are not assigned a value for
s->cache_miss in cached_dev_cache_miss(), for example, a bypassed IO
(s->iop.bypass = 1), or the cache_bio allocate failed. In these situations,
it will go to out_put or out_submit, and s->cache_miss is null, which leads
bch_mark_cache_accounting() to treat this IO as a hit IO.

[ML: applied by 3-way merge]

Signed-off-by: tang.junhui 
Reviewed-by: Michael Lyle 
Reviewed-by: Coly Li 
Signed-off-by: Jens Axboe 
Signed-off-by: Ben Hutchings

dm cache: destroy migration_cache if cache target registration failed

2018-12-16T22:09:39+00:00

commit c7cd55504a5b0fc826a2cd9540845979d24ae542 upstream.

Commit 7e6358d244e47 ("dm: fix various targets to dm_register_target
after module __init resources created") inadvertently introduced this
bug when it moved dm_register_target() after the call to KMEM_CACHE().

Fixes: 7e6358d244e47 ("dm: fix various targets to dm_register_target after module __init resources created")
Signed-off-by: Shenghui Wang 
Signed-off-by: Mike Snitzer 
Signed-off-by: Ben Hutchings

bcache: add separate workqueue for journal_write to avoid deadlock

2018-12-16T22:09:27+00:00

commit 0f843e65d9eef4936929bb036c5f771fb261eea4 upstream.

After write SSD completed, bcache schedules journal_write work to
system_wq, which is a public workqueue in system, without WQ_MEM_RECLAIM
flag. system_wq is also a bound wq, and there may be no idle kworker on
current processor. Creating a new kworker may unfortunately need to
reclaim memory first, by shrinking cache and slab used by vfs, which
depends on bcache device. That's a deadlock.

This patch create a new workqueue for journal_write with WQ_MEM_RECLAIM
flag. It's rescuer thread will work to avoid the deadlock.

Signed-off-by: Guoju Fang 
Signed-off-by: Coly Li 
Signed-off-by: Jens Axboe 
Signed-off-by: Ben Hutchings