linux-stable.git/drivers/md/md-bitmap.c, branch v6.6.86

md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime

2025-02-27T12:10:44+00:00

[ Upstream commit 8d28d0ddb986f56920ac97ae704cc3340a699a30 ]

After commit ec6bb299c7c3 ("md/md-bitmap: add 'sync_size' into struct
md_bitmap_stats"), following panic is reported:

Oops: general protection fault, probably for non-canonical address
RIP: 0010:bitmap_get_stats+0x2b/0xa0
Call Trace:
 
 md_seq_show+0x2d2/0x5b0
 seq_read_iter+0x2b9/0x470
 seq_read+0x12f/0x180
 proc_reg_read+0x57/0xb0
 vfs_read+0xf6/0x380
 ksys_read+0x6c/0xf0
 do_syscall_64+0x82/0x170
 entry_SYSCALL_64_after_hwframe+0x76/0x7e

Root cause is that bitmap_get_stats() can be called at anytime if mddev
is still there, even if bitmap is destroyed, or not fully initialized.
Deferenceing bitmap in this case can crash the kernel. Meanwhile, the
above commit start to deferencing bitmap->storage, make the problem
easier to trigger.

Fix the problem by protecting bitmap_get_stats() with bitmap_info.mutex.

Cc: stable@vger.kernel.org # v6.12+
Fixes: 32a7627cf3a3 ("[PATCH] md: optimised resync using Bitmap based intent logging")
Reported-and-tested-by: Harshit Mogalapalli 
Closes: https://lore.kernel.org/linux-raid/ca3a91a2-50ae-4f68-b317-abd9889f3907@oracle.com/T/#m6e5086c95201135e4941fe38f9efa76daf9666c5
Signed-off-by: Yu Kuai 
Link: https://lore.kernel.org/r/20250124092055.4050195-1-yukuai1@huaweicloud.com
Signed-off-by: Song Liu 
Signed-off-by: Sasha Levin

md/md-bitmap: add 'sync_size' into struct md_bitmap_stats

2025-02-27T12:10:44+00:00

[ Upstream commit ec6bb299c7c3dd4ca1724d13d5f5fae3ee54fc65 ]

To avoid dereferencing bitmap directly in md-cluster to prepare
inventing a new bitmap.

BTW, also fix following checkpatch warnings:

WARNING: Deprecated use of 'kmap_atomic', prefer 'kmap_local_page' instead
WARNING: Deprecated use of 'kunmap_atomic', prefer 'kunmap_local' instead

Signed-off-by: Yu Kuai 
Link: https://lore.kernel.org/r/20240826074452.1490072-7-yukuai1@huaweicloud.com
Signed-off-by: Song Liu 
Stable-dep-of: 8d28d0ddb986 ("md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime")
Signed-off-by: Sasha Levin

md/md-bitmap: replace md_bitmap_status() with a new helper md_bitmap_get_stats()

2025-02-27T12:10:44+00:00

[ Upstream commit 38f287d7e495ae00d4481702f44ff7ca79f5c9bc ]

There are no functional changes, and the new helper will be used in
multiple places in following patches to avoid dereferencing bitmap
directly.

Signed-off-by: Yu Kuai 
Link: https://lore.kernel.org/r/20240826074452.1490072-3-yukuai1@huaweicloud.com
Signed-off-by: Song Liu 
Stable-dep-of: 8d28d0ddb986 ("md/md-bitmap: Synchronize bitmap_get_stats() with bitmap lifetime")
Signed-off-by: Sasha Levin

md/md-bitmap: move bitmap_{start, end}write to md upper layer

2025-02-21T12:57:26+00:00

commit cd5fc653381811f1e0ba65f5d169918cab61476f upstream.

There are two BUG reports that raid5 will hang at
bitmap_startwrite([1],[2]), root cause is that bitmap start write and end
write is unbalanced, it's not quite clear where, and while reviewing raid5
code, it's found that bitmap operations can be optimized. For example,
for a 4 disks raid5, with chunksize=8k, if user issue a IO (0 + 48k) to
the array:

┌────────────────────────────────────────────────────────────┐
│chunk 0                                                     │
│      ┌────────────┬─────────────┬─────────────┬────────────┼
│  sh0 │A0: 0 + 4k  │A1: 8k + 4k  │A2: 16k + 4k │A3: P       │
│      ┼────────────┼─────────────┼─────────────┼────────────┼
│  sh1 │B0: 4k + 4k │B1: 12k + 4k │B2: 20k + 4k │B3: P       │
┼──────┴────────────┴─────────────┴─────────────┴────────────┼
│chunk 1                                                     │
│      ┌────────────┬─────────────┬─────────────┬────────────┤
│  sh2 │C0: 24k + 4k│C1: 32k + 4k │C2: P        │C3: 40k + 4k│
│      ┼────────────┼─────────────┼─────────────┼────────────┼
│  sh3 │D0: 28k + 4k│D1: 36k + 4k │D2: P        │D3: 44k + 4k│
└──────┴────────────┴─────────────┴─────────────┴────────────┘

Before this patch, 4 stripe head will be used, and each sh will attach
bio for 3 disks, and each attached bio will trigger
bitmap_startwrite() once, which means total 12 times.
 - 3 times (0 + 4k), for (A0, A1 and A2)
 - 3 times (4 + 4k), for (B0, B1 and B2)
 - 3 times (8 + 4k), for (C0, C1 and C3)
 - 3 times (12 + 4k), for (D0, D1 and D3)

After this patch, md upper layer will calculate that IO range (0 + 48k)
is corresponding to the bitmap (0 + 16k), and call bitmap_startwrite()
just once.

Noted that this patch will align bitmap ranges to the chunks, for example,
if user issue a IO (0 + 4k) to array:

- Before this patch, 1 time (0 + 4k), for A0;
- After this patch, 1 time (0 + 8k) for chunk 0;

Usually, one bitmap bit will represent more than one disk chunk, and this
doesn't have any difference. And even if user really created a array
that one chunk contain multiple bits, the overhead is that more data
will be recovered after power failure.

Also remove STRIPE_BITMAP_PENDING since it's not used anymore.

[1] https://lore.kernel.org/all/CAJpMwyjmHQLvm6zg1cmQErttNNQPDAAXPKM3xgTjMhbfts986Q@mail.gmail.com/
[2] https://lore.kernel.org/all/ADF7D720-5764-4AF3-B68E-1845988737AA@flyingcircus.io/

Signed-off-by: Yu Kuai 
Link: https://lore.kernel.org/r/20250109015145.158868-6-yukuai1@huaweicloud.com
Signed-off-by: Song Liu 
[There is no bitmap_operations, resolve conflicts by replacing
bitmap_ops->{startwrite, endwrite} with md_bitmap_{startwrite, endwrite}]
Signed-off-by: Yu Kuai 
Signed-off-by: Greg Kroah-Hartman

md/md-bitmap: remove the last parameter for bimtap_ops->endwrite()

2025-02-21T12:57:26+00:00

commit 4f0e7d0e03b7b80af84759a9e7cfb0f81ac4adae upstream.

For the case that IO failed for one rdev, the bit will be mark as NEEDED
in following cases:

1) If badblocks is set and rdev is not faulty;
2) If rdev is faulty;

Case 1) is useless because synchronize data to badblocks make no sense.
Case 2) can be replaced with mddev->degraded.

Also remove R1BIO_Degraded, R10BIO_Degraded and STRIPE_DEGRADED since
case 2) no longer use them.

Signed-off-by: Yu Kuai 
Link: https://lore.kernel.org/r/20250109015145.158868-3-yukuai1@huaweicloud.com
Signed-off-by: Song Liu 
[ Resolve minor conflicts ]
Signed-off-by: Yu Kuai 
Signed-off-by: Greg Kroah-Hartman

md/md-bitmap: factor behind write counters out from bitmap_{start/end}write()

2025-02-21T12:57:25+00:00

commit 08c50142a128dcb2d7060aa3b4c5db8837f7a46a upstream.

behind_write is only used in raid1, prepare to refactor
bitmap_{start/end}write(), there are no functional changes.

Signed-off-by: Yu Kuai 
Reviewed-by: Xiao Ni 
Link: https://lore.kernel.org/r/20250109015145.158868-2-yukuai1@huaweicloud.com
Signed-off-by: Song Liu 
[There is no bitmap_operations, resolve conflicts by exporting new api
md_bitmap_{start,end}_behind_write]
Signed-off-by: Yu Kuai 
Signed-off-by: Greg Kroah-Hartman

md/md-bitmap: Add missing destroy_work_on_stack()

2024-12-09T09:33:01+00:00

commit 6012169e8aae9c0eda38bbedcd7a1540a81220ae upstream.

This commit add missed destroy_work_on_stack() operations for
unplug_work.work in bitmap_unplug_async().

Fixes: a022325ab970 ("md/md-bitmap: add a new helper to unplug bitmap asynchrously")
Cc: stable@vger.kernel.org
Signed-off-by: Yuan Can 
Reviewed-by: Yu Kuai 
Link: https://lore.kernel.org/r/20241105130105.127336-1-yuancan@huawei.com
Signed-off-by: Song Liu 
Signed-off-by: Greg Kroah-Hartman

md/md-bitmap: fix writing non bitmap pages

2024-08-03T06:54:18+00:00

commit ab99a87542f194f28e2364a42afbf9fb48b1c724 upstream.

__write_sb_page() rounds up the io size to the optimal io size if it
doesn't exceed the data offset, but it doesn't check the final size
exceeds the bitmap length.

For example:
page count      - 1
page size       - 4K
data offset     - 1M
optimal io size - 256K

The final io size would be 256K (64 pages) but md_bitmap_storage_alloc()
allocated 1 page, the IO would write 1 valid page and 63 pages that
happens to be allocated afterwards. This leaks memory to the raid device
superblock.

This issue caused a data transfer failure in nvme-tcp. The network
drivers checks the first page of an IO with sendpage_ok(), it returns
true if the page isn't a slabpage and refcount >= 1. If the page
!sendpage_ok() the network driver disables MSG_SPLICE_PAGES.

As of now the network layer assumes all the pages of the IO are
sendpage_ok() when MSG_SPLICE_PAGES is on.

The bitmap pages aren't slab pages, the first page of the IO is
sendpage_ok(), but the additional pages that happens to be allocated
after the bitmap pages might be !sendpage_ok(). That cause
skb_splice_from_iter() to stop the data transfer, in the case below it
hangs 'mdadm --create'.

The bug is reproducible, in order to reproduce we need nvme-over-tcp
controllers with optimal IO size bigger than PAGE_SIZE. Creating a raid
with bitmap over those devices reproduces the bug.

In order to simulate large optimal IO size you can use dm-stripe with a
single device.
Script to reproduce the issue on top of brd devices using dm-stripe is
attached below (will be added to blktest).

I have added some logs to test the theory:
...
md: created bitmap (1 pages) for device md127
__write_sb_page before md_super_write offset: 16, size: 262144. pfn: 0x53ee
=== __write_sb_page before md_super_write. logging pages ===
pfn: 0x53ee, slab: 0 <-- the only page that allocated for the bitmap
pfn: 0x53ef, slab: 1
pfn: 0x53f0, slab: 0
pfn: 0x53f1, slab: 0
pfn: 0x53f2, slab: 0
pfn: 0x53f3, slab: 1
...
nvme_tcp: sendpage_ok - pfn: 0x53ee, len: 262144, offset: 0
skbuff: before sendpage_ok() - pfn: 0x53ee
skbuff: before sendpage_ok() - pfn: 0x53ef
WARNING at net/core/skbuff.c:6848 skb_splice_from_iter+0x142/0x450
skbuff: !sendpage_ok - pfn: 0x53ef. is_slab: 1, page_count: 1
...

Cc: stable@vger.kernel.org
Reviewed-by: Christoph Hellwig 
Signed-off-by: Ofir Gal 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20240607072748.3182199-1-ofir.gal@volumez.com
Signed-off-by: Greg Kroah-Hartman

md: fix resync softlockup when bitmap size is less than array size

2024-06-12T09:11:34+00:00

[ Upstream commit f0e729af2eb6bee9eb58c4df1087f14ebaefe26b ]

Is is reported that for dm-raid10, lvextend + lvchange --syncaction will
trigger following softlockup:

kernel:watchdog: BUG: soft lockup - CPU#3 stuck for 26s! [mdX_resync:6976]
CPU: 7 PID: 3588 Comm: mdX_resync Kdump: loaded Not tainted 6.9.0-rc4-next-20240419 #1
RIP: 0010:_raw_spin_unlock_irq+0x13/0x30
Call Trace:
 
 md_bitmap_start_sync+0x6b/0xf0
 raid10_sync_request+0x25c/0x1b40 [raid10]
 md_do_sync+0x64b/0x1020
 md_thread+0xa7/0x170
 kthread+0xcf/0x100
 ret_from_fork+0x30/0x50
 ret_from_fork_asm+0x1a/0x30

And the detailed process is as follows:

md_do_sync
 j = mddev->resync_min
 while (j < max_sectors)
  sectors = raid10_sync_request(mddev, j, &skipped)
   if (!md_bitmap_start_sync(..., &sync_blocks))
    // md_bitmap_start_sync set sync_blocks to 0
    return sync_blocks + sectors_skippe;
  // sectors = 0;
  j += sectors;
  // j never change

Root cause is that commit 301867b1c168 ("md/raid10: check
slab-out-of-bounds in md_bitmap_get_counter") return early from
md_bitmap_get_counter(), without setting returned blocks.

Fix this problem by always set returned blocks from
md_bitmap_get_counter"(), as it used to be.

Noted that this patch just fix the softlockup problem in kernel, the
case that bitmap size doesn't match array size still need to be fixed.

Fixes: 301867b1c168 ("md/raid10: check slab-out-of-bounds in md_bitmap_get_counter")
Reported-and-tested-by: Nigel Croxon 
Closes: https://lore.kernel.org/all/71ba5272-ab07-43ba-8232-d2da642acb4e@redhat.com/
Signed-off-by: Yu Kuai 
Link: https://lore.kernel.org/r/20240422065824.2516-1-yukuai1@huaweicloud.com
Signed-off-by: Song Liu 
Signed-off-by: Sasha Levin

md/md-bitmap: fix incorrect usage for sb_index

2024-04-03T13:28:21+00:00

[ Upstream commit ecbd8ebb51bf7e4939d83b9e6022a55cac44ef06 ]

Commit d7038f951828 ("md-bitmap: don't use ->index for pages backing the
bitmap file") removed page->index from bitmap code, but left wrong code
logic for clustered-md. current code never set slot offset for cluster
nodes, will sometimes cause crash in clustered env.

Call trace (partly):
 md_bitmap_file_set_bit+0x110/0x1d8 [md_mod]
 md_bitmap_startwrite+0x13c/0x240 [md_mod]
 raid1_make_request+0x6b0/0x1c08 [raid1]
 md_handle_request+0x1dc/0x368 [md_mod]
 md_submit_bio+0x80/0xf8 [md_mod]
 __submit_bio+0x178/0x300
 submit_bio_noacct_nocheck+0x11c/0x338
 submit_bio_noacct+0x134/0x614
 submit_bio+0x28/0xdc
 submit_bh_wbc+0x130/0x1cc
 submit_bh+0x1c/0x28

Fixes: d7038f951828 ("md-bitmap: don't use ->index for pages backing the bitmap file")
Cc: stable@vger.kernel.org # v6.6+
Signed-off-by: Heming Zhao 
Reviewed-by: Christoph Hellwig 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20240223121128.28985-1-heming.zhao@suse.com
Signed-off-by: Sasha Levin