linux-stable.git/drivers/md, branch v5.4.223

md: Replace snprintf with scnprintf

2022-10-26T11:23:00+00:00

commit 1727fd5015d8f93474148f94e34cda5aa6ad4a43 upstream.

Current code produces a warning as shown below when total characters
in the constituent block device names plus the slashes exceeds 200.
snprintf() returns the number of characters generated from the given
input, which could cause the expression “200 – len” to wrap around
to a large positive number. Fix this by using scnprintf() instead,
which returns the actual number of characters written into the buffer.

[ 1513.267938] ------------[ cut here ]------------
[ 1513.267943] WARNING: CPU: 15 PID: 37247 at /lib/vsprintf.c:2509 vsnprintf+0x2c8/0x510
[ 1513.267944] Modules linked in:  
[ 1513.267969] CPU: 15 PID: 37247 Comm: mdadm Not tainted 5.4.0-1085-azure #90~18.04.1-Ubuntu
[ 1513.267969] Hardware name: Microsoft Corporation Virtual Machine/Virtual Machine, BIOS Hyper-V UEFI Release v4.1 05/09/2022
[ 1513.267971] RIP: 0010:vsnprintf+0x2c8/0x510
<-snip->
[ 1513.267982] Call Trace:
[ 1513.267986]  snprintf+0x45/0x70
[ 1513.267990]  ? disk_name+0x71/0xa0
[ 1513.267993]  dump_zones+0x114/0x240 [raid0]
[ 1513.267996]  ? _cond_resched+0x19/0x40
[ 1513.267998]  raid0_run+0x19e/0x270 [raid0]
[ 1513.268000]  md_run+0x5e0/0xc50
[ 1513.268003]  ? security_capable+0x3f/0x60
[ 1513.268005]  do_md_run+0x19/0x110
[ 1513.268006]  md_ioctl+0x195e/0x1f90
[ 1513.268007]  blkdev_ioctl+0x91f/0x9f0
[ 1513.268010]  block_ioctl+0x3d/0x50
[ 1513.268012]  do_vfs_ioctl+0xa9/0x640
[ 1513.268014]  ? __fput+0x162/0x260
[ 1513.268016]  ksys_ioctl+0x75/0x80
[ 1513.268017]  __x64_sys_ioctl+0x1a/0x20
[ 1513.268019]  do_syscall_64+0x5e/0x200
[ 1513.268021]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Fixes: 766038846e875 ("md/raid0: replace printk() with pr_*()")
Reviewed-by: Michael Kelley 
Acked-by: Guoqing Jiang 
Signed-off-by: Saurabh Sengar 
Signed-off-by: Song Liu 
Signed-off-by: Greg Kroah-Hartman

md/raid5: Wait for MD_SB_CHANGE_PENDING in raid5d

2022-10-26T11:22:57+00:00

[ Upstream commit 5e2cf333b7bd5d3e62595a44d598a254c697cd74 ]

A complicated deadlock exists when using the journal and an elevated
group_thrtead_cnt. It was found with loop devices, but its not clear
whether it can be seen with real disks. The deadlock can occur simply
by writing data with an fio script.

When the deadlock occurs, multiple threads will hang in different ways:

 1) The group threads will hang in the blk-wbt code with bios waiting to
    be submitted to the block layer:

        io_schedule+0x70/0xb0
        rq_qos_wait+0x153/0x210
        wbt_wait+0x115/0x1b0
        io_schedule+0x70/0xb0
        rq_qos_wait+0x153/0x210
        wbt_wait+0x115/0x1b0
        __rq_qos_throttle+0x38/0x60
        blk_mq_submit_bio+0x589/0xcd0
        wbt_wait+0x115/0x1b0
        __rq_qos_throttle+0x38/0x60
        blk_mq_submit_bio+0x589/0xcd0
        __submit_bio+0xe6/0x100
        submit_bio_noacct_nocheck+0x42e/0x470
        submit_bio_noacct+0x4c2/0xbb0
        ops_run_io+0x46b/0x1a30
        handle_stripe+0xcd3/0x36b0
        handle_active_stripes.constprop.0+0x6f6/0xa60
        raid5_do_work+0x177/0x330

    Or:
        io_schedule+0x70/0xb0
        rq_qos_wait+0x153/0x210
        wbt_wait+0x115/0x1b0
        __rq_qos_throttle+0x38/0x60
        blk_mq_submit_bio+0x589/0xcd0
        __submit_bio+0xe6/0x100
        submit_bio_noacct_nocheck+0x42e/0x470
        submit_bio_noacct+0x4c2/0xbb0
        flush_deferred_bios+0x136/0x170
        raid5_do_work+0x262/0x330

 2) The r5l_reclaim thread will hang in the same way, submitting a
    bio to the block layer:

        io_schedule+0x70/0xb0
        rq_qos_wait+0x153/0x210
        wbt_wait+0x115/0x1b0
        __rq_qos_throttle+0x38/0x60
        blk_mq_submit_bio+0x589/0xcd0
        __submit_bio+0xe6/0x100
        submit_bio_noacct_nocheck+0x42e/0x470
        submit_bio_noacct+0x4c2/0xbb0
        submit_bio+0x3f/0xf0
        md_super_write+0x12f/0x1b0
        md_update_sb.part.0+0x7c6/0xff0
        md_update_sb+0x30/0x60
        r5l_do_reclaim+0x4f9/0x5e0
        r5l_reclaim_thread+0x69/0x30b

    However, before hanging, the MD_SB_CHANGE_PENDING flag will be
    set for sb_flags in r5l_write_super_and_discard_space(). This
    flag will never be cleared because the submit_bio() call never
    returns.

 3) Due to the MD_SB_CHANGE_PENDING flag being set, handle_stripe()
    will do no processing on any pending stripes and re-set
    STRIPE_HANDLE. This will cause the raid5d thread to enter an
    infinite loop, constantly trying to handle the same stripes
    stuck in the queue.

    The raid5d thread has a blk_plug that holds a number of bios
    that are also stuck waiting seeing the thread is in a loop
    that never schedules. These bios have been accounted for by
    blk-wbt thus preventing the other threads above from
    continuing when they try to submit bios. --Deadlock.

To fix this, add the same wait_event() that is used in raid5_do_work()
to raid5d() such that if MD_SB_CHANGE_PENDING is set, the thread will
schedule and wait until the flag is cleared. The schedule action will
flush the plug which will allow the r5l_reclaim thread to continue,
thus preventing the deadlock.

However, md_check_recovery() calls can also clear MD_SB_CHANGE_PENDING
from the same thread and can thus deadlock if the thread is put to
sleep. So avoid waiting if md_check_recovery() is being called in the
loop.

It's not clear when the deadlock was introduced, but the similar
wait_event() call in raid5_do_work() was added in 2017 by this
commit:

    16d997b78b15 ("md/raid5: simplfy delaying of writes while metadata
                   is updated.")

Link: https://lore.kernel.org/r/7f3b87b6-b52a-f737-51d7-a4eec5c44112@deltatee.com
Signed-off-by: Logan Gunthorpe 
Signed-off-by: Song Liu 
Signed-off-by: Sasha Levin

bcache: fix set_at_max_writeback_rate() for multiple attached devices

2022-10-26T11:22:57+00:00

[ Upstream commit d2d05b88035d2d51a5bb6c5afec88a0880c73df4 ]

Inside set_at_max_writeback_rate() the calculation in following if()
check is wrong,
	if (atomic_inc_return(&c->idle_counter) <
	    atomic_read(&c->attached_dev_nr) * 6)

Because each attached backing device has its own writeback thread
running and increasing c->idle_counter, the counter increates much
faster than expected. The correct calculation should be,
	(counter / dev_nr) < dev_nr * 6
which equals to,
	counter < dev_nr * dev_nr * 6

This patch fixes the above mistake with correct calculation, and helper
routine idle_counter_exceeded() is added to make code be more clear.

Reported-by: Mingzhe Zou 
Signed-off-by: Coly Li 
Acked-by: Mingzhe Zou 
Link: https://lore.kernel.org/r/20220919161647.81238-6-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

md/raid5: Ensure stripe_fill happens on non-read IO with journal

2022-10-26T11:22:39+00:00

[ Upstream commit e2eed85bc75138a9eeb63863d20f8904ac42a577 ]

When doing degrade/recover tests using the journal a kernel BUG
is hit at drivers/md/raid5.c:4381 in handle_parity_checks5():

  BUG_ON(!test_bit(R5_UPTODATE, &dev->flags));

This was found to occur because handle_stripe_fill() was skipped
for stripes in the journal due to a condition in that function.
Thus blocks were not fetched and R5_UPTODATE was not set when
the code reached handle_parity_checks5().

To fix this, don't skip handle_stripe_fill() unless the stripe is
for read.

Fixes: 07e83364845e ("md/r5cache: shift complex rmw from read path to write path")
Link: https://lore.kernel.org/linux-raid/e05c4239-41a9-d2f7-3cfa-4aa9d2cea8c1@deltatee.com/
Suggested-by: Song Liu 
Signed-off-by: Logan Gunthorpe 
Signed-off-by: Song Liu 
Signed-off-by: Sasha Levin

md: call __md_stop_writes in md_stop

2022-09-05T08:27:44+00:00

commit 0dd84b319352bb8ba64752d4e45396d8b13e6018 upstream.

From the link [1], we can see raid1d was running even after the path
raid_dtr -> md_stop -> __md_stop.

Let's stop write first in destructor to align with normal md-raid to
fix the KASAN issue.

[1]. https://lore.kernel.org/linux-raid/CAPhsuW5gc4AakdGNdF8ubpezAuDLFOYUO_sfMZcec6hQFm8nhg@mail.gmail.com/T/#m7f12bf90481c02c6d2da68c64aeed4779b7df74a

Fixes: 48df498daf62 ("md: move bitmap_destroy to the beginning of __md_stop")
Reported-by: Mikulas Patocka 
Signed-off-by: Guoqing Jiang 
Signed-off-by: Song Liu 
Signed-off-by: Greg Kroah-Hartman

drivers:md:fix a potential use-after-free bug

2022-08-25T09:18:35+00:00

[ Upstream commit 104212471b1c1817b311771d817fb692af983173 ]

In line 2884, "raid5_release_stripe(sh);" drops the reference to sh and
may cause sh to be released. However, sh is subsequently used in lines
2886 "if (sh->batch_head && sh != sh->batch_head)". This may result in an
use-after-free bug.

It can be fixed by moving "raid5_release_stripe(sh);" to the bottom of
the function.

Signed-off-by: Wentao_Liang 
Signed-off-by: Song Liu 
Signed-off-by: Jens Axboe 
Signed-off-by: Sasha Levin

dm writecache: set a default MAX_WRITEBACK_JOBS

2022-08-25T09:18:14+00:00

commit ca7dc242e358e46d963b32f9d9dd829785a9e957 upstream.

dm-writecache has the capability to limit the number of writeback jobs
in progress. However, this feature was off by default. As such there
were some out-of-memory crashes observed when lowering the low
watermark while the cache is full.

This commit enables writeback limit by default. It is set to 256MiB or
1/16 of total system memory, whichever is smaller.

Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm thin: fix use-after-free crash in dm_sm_register_threshold_callback

2022-08-25T09:18:14+00:00

commit 3534e5a5ed2997ca1b00f44a0378a075bd05e8a3 upstream.

Fault inject on pool metadata device reports:
  BUG: KASAN: use-after-free in dm_pool_register_metadata_threshold+0x40/0x80
  Read of size 8 at addr ffff8881b9d50068 by task dmsetup/950

  CPU: 7 PID: 950 Comm: dmsetup Tainted: G        W         5.19.0-rc6 #1
  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-1.fc33 04/01/2014
  Call Trace:
   
   dump_stack_lvl+0x34/0x44
   print_address_description.constprop.0.cold+0xeb/0x3f4
   kasan_report.cold+0xe6/0x147
   dm_pool_register_metadata_threshold+0x40/0x80
   pool_ctr+0xa0a/0x1150
   dm_table_add_target+0x2c8/0x640
   table_load+0x1fd/0x430
   ctl_ioctl+0x2c4/0x5a0
   dm_ctl_ioctl+0xa/0x10
   __x64_sys_ioctl+0xb3/0xd0
   do_syscall_64+0x35/0x80
   entry_SYSCALL_64_after_hwframe+0x46/0xb0

This can be easily reproduced using:
  echo offline > /sys/block/sda/device/state
  dd if=/dev/zero of=/dev/mapper/thin bs=4k count=10
  dmsetup load pool --table "0 20971520 thin-pool /dev/sda /dev/sdb 128 0 0"

If a metadata commit fails, the transaction will be aborted and the
metadata space maps will be destroyed. If a DM table reload then
happens for this failed thin-pool, a use-after-free will occur in
dm_sm_register_threshold_callback (called from
dm_pool_register_metadata_threshold).

Fix this by in dm_pool_register_metadata_threshold() by returning the
-EINVAL error if the thin-pool is in fail mode. Also fail pool_ctr()
with a new error message: "Error registering metadata threshold".

Fixes: ac8c3f3df65e4 ("dm thin: generate event when metadata threshold passed")
Cc: stable@vger.kernel.org
Reported-by: Hulk Robot 
Signed-off-by: Luo Meng 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm raid: fix address sanitizer warning in raid_status

2022-08-25T09:18:14+00:00

commit 1fbeea217d8f297fe0e0956a1516d14ba97d0396 upstream.

There is this warning when using a kernel with the address sanitizer
and running this testsuite:
https://gitlab.com/cki-project/kernel-tests/-/tree/main/storage/swraid/scsi_raid

==================================================================
BUG: KASAN: slab-out-of-bounds in raid_status+0x1747/0x2820 [dm_raid]
Read of size 4 at addr ffff888079d2c7e8 by task lvcreate/13319
CPU: 0 PID: 13319 Comm: lvcreate Not tainted 5.18.0-0.rc3. #1
Hardware name: Red Hat KVM, BIOS 0.5.1 01/01/2011
Call Trace:
 
 dump_stack_lvl+0x6a/0x9c
 print_address_description.constprop.0+0x1f/0x1e0
 print_report.cold+0x55/0x244
 kasan_report+0xc9/0x100
 raid_status+0x1747/0x2820 [dm_raid]
 dm_ima_measure_on_table_load+0x4b8/0xca0 [dm_mod]
 table_load+0x35c/0x630 [dm_mod]
 ctl_ioctl+0x411/0x630 [dm_mod]
 dm_ctl_ioctl+0xa/0x10 [dm_mod]
 __x64_sys_ioctl+0x12a/0x1a0
 do_syscall_64+0x5b/0x80

The warning is caused by reading conf->max_nr_stripes in raid_status. The
code in raid_status reads mddev->private, casts it to struct r5conf and
reads the entry max_nr_stripes.

However, if we have different raid type than 4/5/6, mddev->private
doesn't point to struct r5conf; it may point to struct r0conf, struct
r1conf, struct r10conf or struct mpconf. If we cast a pointer to one
of these structs to struct r5conf, we will be reading invalid memory
and KASAN warns about it.

Fix this bug by reading struct r5conf only if raid type is 4, 5 or 6.

Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman

dm raid: fix address sanitizer warning in raid_resume

2022-08-25T09:18:14+00:00

commit 7dad24db59d2d2803576f2e3645728866a056dab upstream.

There is a KASAN warning in raid_resume when running the lvm test
lvconvert-raid.sh. The reason for the warning is that mddev->raid_disks
is greater than rs->raid_disks, so the loop touches one entry beyond
the allocated length.

Cc: stable@vger.kernel.org
Signed-off-by: Mikulas Patocka 
Signed-off-by: Mike Snitzer 
Signed-off-by: Greg Kroah-Hartman