linux-stable.git/drivers/md, branch v5.4.252

md/raid10: prevent soft lockup while flush writes

2023-07-27T06:37:41+00:00

[ Upstream commit 010444623e7f4da6b4a4dd603a7da7469981e293 ]

Currently, there is no limit for raid1/raid10 plugged bio. While flushing
writes, raid1 has cond_resched() while raid10 doesn't, and too many
writes can cause soft lockup.

Follow up soft lockup can be triggered easily with writeback test for
raid10 with ramdisks:

watchdog: BUG: soft lockup - CPU#10 stuck for 27s! [md0_raid10:1293]
Call Trace:
 
 call_rcu+0x16/0x20
 put_object+0x41/0x80
 __delete_object+0x50/0x90
 delete_object_full+0x2b/0x40
 kmemleak_free+0x46/0xa0
 slab_free_freelist_hook.constprop.0+0xed/0x1a0
 kmem_cache_free+0xfd/0x300
 mempool_free_slab+0x1f/0x30
 mempool_free+0x3a/0x100
 bio_free+0x59/0x80
 bio_put+0xcf/0x2c0
 free_r10bio+0xbf/0xf0
 raid_end_bio_io+0x78/0xb0
 one_write_done+0x8a/0xa0
 raid10_end_write_request+0x1b4/0x430
 bio_endio+0x175/0x320
 brd_submit_bio+0x3b9/0x9b7 [brd]
 __submit_bio+0x69/0xe0
 submit_bio_noacct_nocheck+0x1e6/0x5a0
 submit_bio_noacct+0x38c/0x7e0
 flush_pending_writes+0xf0/0x240
 raid10d+0xac/0x1ed0

Fix the problem by adding cond_resched() to raid10 like what raid1 did.

Note that unlimited plugged bio still need to be optimized, for example,
in the case of lots of dirty pages writeback, this will take lots of
memory and io will spend a long time in plug, hence io latency is bad.

Signed-off-by: Yu Kuai 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20230529131106.2123367-2-yukuai1@huaweicloud.com
Signed-off-by: Sasha Levin

md: fix data corruption for raid456 when reshape restart while grow up

2023-07-27T06:37:41+00:00

[ Upstream commit 873f50ece41aad5c4f788a340960c53774b5526e ]

Currently, if reshape is interrupted, echo "reshape" to sync_action will
restart reshape from scratch, for example:

echo frozen > sync_action
echo reshape > sync_action

This will corrupt data before reshape_position if the array is growing,
fix the problem by continue reshape from reshape_position.

Reported-by: Peter Neuwirth 
Link: https://lore.kernel.org/linux-raid/e2f96772-bfbc-f43b-6da1-f520e5164536@online.de/
Signed-off-by: Yu Kuai 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20230512015610.821290-3-yukuai1@huaweicloud.com
Signed-off-by: Sasha Levin

md/raid0: add discard support for the 'original' layout

2023-07-27T06:37:37+00:00

commit e836007089ba8fdf24e636ef2b007651fb4582e6 upstream.

We've found that using raid0 with the 'original' layout and discard
enabled with different disk sizes (such that at least two zones are
created) can result in data corruption. This is due to the fact that
the discard handling in 'raid0_handle_discard()' assumes the 'alternate'
layout. We've seen this corruption using ext4 but other filesystems are
likely susceptible as well.

More specifically, while multiple zones are necessary to create the
corruption, the corruption may not occur with multiple zones if they
layout in such a way the layout matches what the 'alternate' layout
would have produced. Thus, not all raid0 devices with the 'original'
layout, different size disks and discard enabled will encounter this
corruption.

The 3.14 kernel inadvertently changed the raid0 disk layout for different
size disks. Thus, running a pre-3.14 kernel and post-3.14 kernel on the
same raid0 array could corrupt data. This lead to the creation of the
'original' layout (to match the pre-3.14 layout) and the 'alternate' layout
(to match the post 3.14 layout) in the 5.4 kernel time frame and an option
to tell the kernel which layout to use (since it couldn't be autodetected).
However, when the 'original' layout was added back to 5.4 discard support
for the 'original' layout was not added leading this issue.

I've been able to reliably reproduce the corruption with the following
test case:

1. create raid0 array with different size disks using original layout
2. mkfs
3. mount -o discard
4. create lots of files
5. remove 1/2 the files
6. fstrim -a (or just the mount point for the raid0 array)
7. umount
8. fsck -fn /dev/md0 (spews all sorts of corruptions)

Let's fix this by adding proper discard support to the 'original' layout.
The fix 'maps' the 'original' layout disks to the order in which they are
read/written such that we can compare the disks in the same way that the
current 'alternate' layout does. A 'disk_shift' field is added to
'struct strip_zone'. This could be computed on the fly in
raid0_handle_discard() but by adding this field, we save some computation
in the discard path.

Note we could also potentially fix this by re-ordering the disks in the
zones that follow the first one, and then always read/writing them using
the 'alternate' layout. However, that is seen as a more substantial change,
and we are attempting the least invasive fix at this time to remedy the
corruption.

I've verified the change using the reproducer mentioned above. Typically,
the corruption is seen after less than 3 iterations, while the patch has
run 500+ iterations.

Cc: NeilBrown 
Cc: Song Liu 
Fixes: c84a1372df92 ("md/raid0: avoid RAID0 data corruption due to layout confusion.")
Cc: stable@vger.kernel.org
Signed-off-by: Jason Baron 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20230623180523.1901230-1-jbaron@akamai.com
Signed-off-by: Greg Kroah-Hartman

bcache: Remove unnecessary NULL point check in node allocations

2023-07-27T06:37:25+00:00

commit 028ddcac477b691dd9205c92f991cc15259d033e upstream.

Due to the previous fix of __bch_btree_node_alloc, the return value will
never be a NULL pointer. So IS_ERR is enough to handle the failure
situation. Fix it by replacing IS_ERR_OR_NULL check by an IS_ERR check.

Fixes: cafe56359144 ("bcache: A block layer cache")
Cc: stable@vger.kernel.org
Signed-off-by: Zheng Wang 
Signed-off-by: Coly Li 
Link: https://lore.kernel.org/r/20230615121223.22502-5-colyli@suse.de
Signed-off-by: Jens Axboe 
Signed-off-by: Greg Kroah-Hartman

md/raid10: fix io loss while replacement replace rdev

2023-07-27T06:37:05+00:00

[ Upstream commit 2ae6aaf76912bae53c74b191569d2ab484f24bf3 ]

When removing a disk with replacement, the replacement will be used to
replace rdev. During this process, there is a brief window in which both
rdev and replacement are read as NULL in raid10_write_request(). This
will result in io not being submitted but it should be.

  //remove				//write
  raid10_remove_disk			raid10_write_request
   mirror->rdev = NULL
					 read rdev -> NULL
   mirror->rdev = mirror->replacement
   mirror->replacement = NULL
					 read replacement -> NULL

Fix it by reading replacement first and rdev later, meanwhile, use smp_mb()
to prevent memory reordering.

Fixes: 475b0321a4df ("md/raid10: writes should get directed to replacement as well as original.")
Signed-off-by: Li Nan 
Reviewed-by: Yu Kuai 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20230602091839.743798-3-linan666@huaweicloud.com
Signed-off-by: Sasha Levin

md/raid10: fix null-ptr-deref of mreplace in raid10_sync_request

2023-07-27T06:37:05+00:00

[ Upstream commit 34817a2441747b48e444cb0e05d84e14bc9443da ]

There are two check of 'mreplace' in raid10_sync_request(). In the first
check, 'need_replace' will be set and 'mreplace' will be used later if
no-Faulty 'mreplace' exists, In the second check, 'mreplace' will be
set to NULL if it is Faulty, but 'need_replace' will not be changed
accordingly. null-ptr-deref occurs if Faulty is set between two check.

Fix it by merging two checks into one. And replace 'need_replace' with
'mreplace' because their values are always the same.

Fixes: ee37d7314a32 ("md/raid10: Fix raid10 replace hang when new added disk faulty")
Signed-off-by: Li Nan 
Reviewed-by: Yu Kuai 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20230527072218.2365857-2-linan666@huaweicloud.com
Signed-off-by: Sasha Levin

md/raid10: fix wrong setting of max_corr_read_errors

2023-07-27T06:37:04+00:00

[ Upstream commit f8b20a405428803bd9881881d8242c9d72c6b2b2 ]

There is no input check when echo md/max_read_errors and overflow might
occur. Add check of input number.

Fixes: 1e50915fe0bb ("raid: improve MD/raid10 handling of correctable read errors.")
Signed-off-by: Li Nan 
Reviewed-by: Yu Kuai 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20230522072535.1523740-3-linan666@huaweicloud.com
Signed-off-by: Sasha Levin

md/raid10: fix overflow of md/safe_mode_delay

2023-07-27T06:37:04+00:00

[ Upstream commit 6beb489b2eed25978523f379a605073f99240c50 ]

There is no input check when echo md/safe_mode_delay in safe_delay_store().
And msec might also overflow when HZ < 1000 in safe_delay_show(), Fix it by
checking overflow in safe_delay_store() and use unsigned long conversion in
safe_delay_show().

Fixes: 72e02075a33f ("md: factor out parsing of fixed-point numbers")
Signed-off-by: Li Nan 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20230522072535.1523740-2-linan666@huaweicloud.com
Signed-off-by: Sasha Levin

md/raid10: check slab-out-of-bounds in md_bitmap_get_counter

2023-07-27T06:37:04+00:00

[ Upstream commit 301867b1c16805aebbc306aafa6ecdc68b73c7e5 ]

If we write a large number to md/bitmap_set_bits, md_bitmap_checkpage()
will return -EINVAL because 'page >= bitmap->pages', but the return value
was not checked immediately in md_bitmap_get_counter() in order to set
*blocks value and slab-out-of-bounds occurs.

Move check of 'page >= bitmap->pages' to md_bitmap_get_counter() and
return directly if true.

Fixes: ef4256733506 ("md/bitmap: optimise scanning of empty bitmaps.")
Signed-off-by: Li Nan 
Reviewed-by: Yu Kuai 
Signed-off-by: Song Liu 
Link: https://lore.kernel.org/r/20230515134808.3936750-2-linan666@huaweicloud.com
Signed-off-by: Sasha Levin

treewide: Remove uninitialized_var() usage

2023-06-09T08:29:01+00:00

commit 3f649ab728cda8038259d8f14492fe400fbab911 upstream.

Using uninitialized_var() is dangerous as it papers over real bugs[1]
(or can in the future), and suppresses unrelated compiler warnings
(e.g. "unused variable"). If the compiler thinks it is uninitialized,
either simply initialize the variable or make compiler changes.

In preparation for removing[2] the[3] macro[4], remove all remaining
needless uses with the following script:

git grep '\buninitialized_var\b' | cut -d: -f1 | sort -u | \
	xargs perl -pi -e \
		's/\buninitialized_var\(([^\)]+)\)/\1/g;
		 s:\s*/\* (GCC be quiet|to make compiler happy) \*/$::g;'

drivers/video/fbdev/riva/riva_hw.c was manually tweaked to avoid
pathological white-space.

No outstanding warnings were found building allmodconfig with GCC 9.3.0
for x86_64, i386, arm64, arm, powerpc, powerpc64le, s390x, mips, sparc64,
alpha, and m68k.

[1] https://lore.kernel.org/lkml/20200603174714.192027-1-glider@google.com/
[2] https://lore.kernel.org/lkml/CA+55aFw+Vbj0i=1TGqCR5vQkCzWJ0QxK6CernOU6eedsudAixw@mail.gmail.com/
[3] https://lore.kernel.org/lkml/CA+55aFwgbgqhbp1fkxvRKEpzyR5J8n1vKT1VZdz9knmPuXhOeg@mail.gmail.com/
[4] https://lore.kernel.org/lkml/CA+55aFz2500WfbKXAx8s67wrm9=yVJu65TpLgN_ybYNv0VEOKA@mail.gmail.com/

Reviewed-by: Leon Romanovsky  # drivers/infiniband and mlx4/mlx5
Acked-by: Jason Gunthorpe  # IB
Acked-by: Kalle Valo  # wireless drivers
Reviewed-by: Chao Yu  # erofs
Signed-off-by: Kees Cook 
Signed-off-by: Greg Kroah-Hartman