linux-stable.git/drivers/md/raid1.c, branch v6.5.2

md/raid1-10: limit the number of plugged bio

2023-06-13T22:25:44+00:00

bio can be added to plug infinitely, and following writeback test can
trigger huge amount of plugged bio:

Test script:
modprobe brd rd_nr=4 rd_size=10485760
mdadm -CR /dev/md0 -l10 -n4 /dev/ram[0123] --assume-clean --bitmap=internal
echo 0 > /proc/sys/vm/dirty_background_ratio
fio -filename=/dev/md0 -ioengine=libaio -rw=write -bs=4k -numjobs=1 -iodepth=128 -name=test

Test result:
Monitor /sys/block/md0/inflight will found that inflight keep increasing
until fio finish writing, after running for about 2 minutes:

[root@fedora ~]# cat /sys/block/md0/inflight
       0  4474191

Fix the problem by limiting the number of plugged bio based on the number
of copies for original bio.

Signed-off-by: Yu Kuai 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20230529131106.2123367-8-yukuai1@huaweicloud.com

md/raid1-10: don't handle pluged bio by daemon thread

2023-06-13T22:25:44+00:00

current->bio_list will be set under submit_bio() context, in this case
bitmap io will be added to the list and wait for current io submission to
finish, while current io submission must wait for bitmap io to be done.
commit 874807a83139 ("md/raid1{,0}: fix deadlock in bitmap_unplug.") fix
the deadlock by handling plugged bio by daemon thread.

On the one hand, the deadlock won't exist after commit a214b949d8e3
("blk-mq: only flush requests from the plug in blk_mq_submit_bio"). On
the other hand, current solution makes it impossible to flush plugged bio
in raid1/10_make_request(), because this will cause that all the writes
will goto daemon thread.

In order to limit the number of plugged bio, commit 874807a83139
("md/raid1{,0}: fix deadlock in bitmap_unplug.") is reverted, and the
deadlock is fixed by handling bitmap io asynchronously.

Signed-off-by: Yu Kuai 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20230529131106.2123367-7-yukuai1@huaweicloud.com

md/raid1-10: factor out a helper to submit normal write

2023-06-13T22:25:43+00:00

There are multiple places to do the same thing, factor out a helper to
prevent redundant code, and the helper will be used in following patch
as well.

Signed-off-by: Yu Kuai 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20230529131106.2123367-4-yukuai1@huaweicloud.com

md/raid1-10: factor out a helper to add bio to plug

2023-06-13T22:25:43+00:00

The code in raid1 and raid10 is identical, prepare to limit the number
of plugged bios.

Signed-off-by: Yu Kuai 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20230529131106.2123367-3-yukuai1@huaweicloud.com

md: protect md_thread with rcu

2023-06-13T22:25:39+00:00

Currently, there are many places that md_thread can be accessed without
protection, following are known scenarios that can cause
null-ptr-dereference or uaf:

1) sync_thread that is allocated and started from md_start_sync()
2) mddev->thread can be accessed directly from timeout_store() and
   md_bitmap_daemon_work()
3) md_unregister_thread() from action_store().

Currently, a global spinlock 'pers_lock' is borrowed to protect
'mddev->thread' in some places, this problem can be fixed likewise,
however, use a global lock for all the cases is not good.

Fix this problem by protecting all md_thread with rcu.

Signed-off-by: Yu Kuai 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20230523021017.3048783-6-yukuai1@huaweicloud.com

md: raid1: use __bio_add_page for adding single page to bio

2023-06-01T15:13:31+00:00

The sync request code uses bio_add_page() to add a page to a newly created bio.
bio_add_page() can fail, but the return value is never checked.

Use __bio_add_page() as adding a single page to a newly created bio is
guaranteed to succeed.

This brings us a step closer to marking bio_add_page() as __must_check.

Reviewed-by: Christoph Hellwig 
Reviewed-by: Damien Le Moal 
Acked-by: Song Liu 
Signed-off-by: Johannes Thumshirn 
Link: https://lore.kernel.org/r/6cf7f66c6e646231200d025dfd5f2d3ae75c8fe5.1685532726.git.johannes.thumshirn@wdc.com
Signed-off-by: Jens Axboe

md: check for failure when adding pages in alloc_behind_master_bio

2023-06-01T15:13:13+00:00

alloc_behind_master_bio() can possibly add multiple pages to a bio, but it
is not checking for the return value of bio_add_page() if adding really
succeeded.

Check if the page adding succeeded and if not bail out.

Reviewed-by: Christoph Hellwig 
Acked-by: Song Liu 
Reviewed-by: Damien Le Moal 
Signed-off-by: Johannes Thumshirn 
Link: https://lore.kernel.org/r/827aa12d44ebf3f50b41b47f5cedc0f80179f2c1.1685532726.git.johannes.thumshirn@wdc.com
[axboe: fold in s/free_page/put_page fix]
Signed-off-by: Jens Axboe

block: remove bio_set_op_attrs

2022-12-07T16:43:12+00:00

This macro is obsolete, so replace the last few uses with open coded
bi_opf assignments.

Signed-off-by: Christoph Hellwig 
Acked-by: Coly Li >
Reviewed-by: Johannes Thumshirn 
Reviewed-by: Bart Van Assche 
Link: https://lore.kernel.org/r/20221206144057.720846-1-hch@lst.de
Signed-off-by: Jens Axboe

md/raid1: stop mdx_raid1 thread when raid1 array run failed

2022-11-14T18:15:35+00:00

fail run raid1 array when we assemble array with the inactive disk only,
but the mdx_raid1 thread were not stop, Even if the associated resources
have been released. it will caused a NULL dereference when we do poweroff.

This causes the following Oops:
    [  287.587787] BUG: kernel NULL pointer dereference, address: 0000000000000070
    [  287.594762] #PF: supervisor read access in kernel mode
    [  287.599912] #PF: error_code(0x0000) - not-present page
    [  287.605061] PGD 0 P4D 0
    [  287.607612] Oops: 0000 [#1] SMP NOPTI
    [  287.611287] CPU: 3 PID: 5265 Comm: md0_raid1 Tainted: G     U            5.10.146 #0
    [  287.619029] Hardware name: xxxxxxx/To be filled by O.E.M, BIOS 5.19 06/16/2022
    [  287.626775] RIP: 0010:md_check_recovery+0x57/0x500 [md_mod]
    [  287.632357] Code: fe 01 00 00 48 83 bb 10 03 00 00 00 74 08 48 89 ......
    [  287.651118] RSP: 0018:ffffc90000433d78 EFLAGS: 00010202
    [  287.656347] RAX: 0000000000000000 RBX: ffff888105986800 RCX: 0000000000000000
    [  287.663491] RDX: ffffc90000433bb0 RSI: 00000000ffffefff RDI: ffff888105986800
    [  287.670634] RBP: ffffc90000433da0 R08: 0000000000000000 R09: c0000000ffffefff
    [  287.677771] R10: 0000000000000001 R11: ffffc90000433ba8 R12: ffff888105986800
    [  287.684907] R13: 0000000000000000 R14: fffffffffffffe00 R15: ffff888100b6b500
    [  287.692052] FS:  0000000000000000(0000) GS:ffff888277f80000(0000) knlGS:0000000000000000
    [  287.700149] CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
    [  287.705897] CR2: 0000000000000070 CR3: 000000000320a000 CR4: 0000000000350ee0
    [  287.713033] Call Trace:
    [  287.715498]  raid1d+0x6c/0xbbb [raid1]
    [  287.719256]  ? __schedule+0x1ff/0x760
    [  287.722930]  ? schedule+0x3b/0xb0
    [  287.726260]  ? schedule_timeout+0x1ed/0x290
    [  287.730456]  ? __switch_to+0x11f/0x400
    [  287.734219]  md_thread+0xe9/0x140 [md_mod]
    [  287.738328]  ? md_thread+0xe9/0x140 [md_mod]
    [  287.742601]  ? wait_woken+0x80/0x80
    [  287.746097]  ? md_register_thread+0xe0/0xe0 [md_mod]
    [  287.751064]  kthread+0x11a/0x140
    [  287.754300]  ? kthread_park+0x90/0x90
    [  287.757974]  ret_from_fork+0x1f/0x30

In fact, when raid1 array run fail, we need to do
md_unregister_thread() before raid1_free().

Signed-off-by: Jiang Li 
Signed-off-by: Song Liu

md/raid1: Use the new blk_opf_t type

2022-07-14T18:14:31+00:00

Improve static type checking by using the new blk_opf_t type for
variables that represent request flags.

Acked-by: Song Liu 
Signed-off-by: Bart Van Assche 
Link: https://lore.kernel.org/r/20220714180729.1065367-35-bvanassche@acm.org
Signed-off-by: Jens Axboe