KCSAN reports a data race between raid1_end_read_request() and
raid1_read_request().
The completion path updates conf->mirrors[disk].head_position in
update_head_pos() without a lock, while the read-balance heuristic reads
the same field locklessly in is_sequential() and choose_best_rdev().
KCSAN report:
=========================
BUG: KCSAN: data-race in raid1_end_read_request / raid1_read_request
write to 0xffff8f0306ba7868 of 8 bytes by interrupt on cpu 9:
raid1_end_read_request+0xb5/0x440
bio_endio+0x3c9/0x3e0
blk_update_request+0x257/0x770
scsi_end_request+0x4d/0x520
scsi_io_completion+0x6f/0x990
scsi_finish_command+0x188/0x280
scsi_complete+0xac/0x160
blk_complete_reqs+0x8e/0xb0
blk_done_softirq+0x1d/0x30
[...]
read to 0xffff8f0306ba7868 of 8 bytes by task 667002 on cpu 11:
raid1_read_request+0x497/0x1a10
raid1_make_request+0xdf/0x1950
md_handle_request+0x2c5/0x700
md_submit_bio+0x126/0x320
__submit_bio+0x2ec/0x3a0
submit_bio_noacct_nocheck+0x572/0x890
[...]
value changed: 0x0000000000000078 -> 0x00000000005fe448
Signed-off-by: Chen Cheng <chencheng@fnnas.com>
Link: https://patch.msgid.link/20260619044114.1208456-1-chencheng@fnnas.com
Signed-off-by: Yu Kuai <yukuai@fygo.io>
raid1 supports REQ_NOWAIT reads by avoiding waits in the barrier path
through wait_read_barrier(). However, a read can still block on a
WriteMostly device when the array uses a bitmap and there are
outstanding behind writes.
In that case raid1 unconditionally calls wait_behind_writes(), which
may sleep until all behind writes complete. As a result, a REQ_NOWAIT
read can block despite the caller explicitly requesting non-blocking
behavior.
This ensures that raid1 consistently honors REQ_NOWAIT reads across all
paths that may otherwise wait for behind writes.
Fixes: 5aa705039c ("md: raid1 add nowait support")
Signed-off-by: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com>
Link: https://patch.msgid.link/20260611083514.754922-1-abd.masalkhi@gmail.com
Signed-off-by: Yu Kuai <yukuai@fygo.io>
raid1_write_request() increments rdev->nr_pending before checking the
badblocks and then immediately decrements it again when a device is
skipped. Move the increment until after the checks succeed so the
reference accounting is easier to follow.
Consolidate the failure paths so that each error label releases exactly
the resources acquired up to that point. err_dec_pending drops pending
references and frees the r1bio, while err_allow_barrier handles the
barrier release before returning.
When a REQ_ATOMIC write cannot be satisfied due to a badblock range,
complete the bio with BLK_STS_NOTSUPP rather than reporting an I/O
error, since the operation is unsupported rather than having failed
during I/O.
Rename max_write_sectors to max_sectors and remove the redundant local
copy.
Signed-off-by: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com>
Link: https://patch.msgid.link/20260613182810.1317258-5-abd.masalkhi@gmail.com
Signed-off-by: Yu Kuai <yukuai@fygo.io>
Pull MD updates and fixes from Yu Kuai:
"Bug Fixes:
- Only requeue dm-raid bios when dm is suspending. (Benjamin Marzinski)
- Reset raid10 read_slot when reusing r10bio for discard. (Chen Cheng)
- Fix raid1/raid10 deadlock in read error recovery path.
(Abd-Alrhman Masalkhi)
- Fix raid1/raid10 error-path detection with md_cloned_bio().
(Abd-Alrhman Masalkhi)
- Fix raid1/raid10 bio accounting for split md cloned bios.
(Abd-Alrhman Masalkhi)
- Fix raid1 nr_pending leak in REQ_ATOMIC bad-block path.
(Abd-Alrhman Masalkhi)
Improvements:
- Skip redundant raid_disks updates when the value is unchanged.
(Abd-Alrhman Masalkhi)
Cleanups:
- Update MAINTAINERS email addresses. (Yu Kuai, Li Nan)
- Clean up raid1 read error handling. (Christoph Hellwig)
- Move the exceed_read_errors condition out of fix_read_error().
(Christoph Hellwig)
- Use str_plural() in raid0 dump_zones(). (Thorsten Blum)"
* tag 'md-7.2-20260531' of https://git.kernel.org/pub/scm/linux/kernel/git/mdraid/linux:
md/raid0: use str_plural helper in dump_zones
raid1: fix nr_pending leak in REQ_ATOMIC bad-block error path
md/raid1: move the exceed_read_errors condition out of fix_read_error
md/raid1: cleanup handle_read_error
md/raid1,raid10: fix bio accounting for split md cloned bios
md/raid1,raid10: fix error-path detection with md_cloned_bio()
md/raid1,raid10: fix deadlock in read error recovery path
md/raid10: reset read_slot when reusing r10bio for discard
md: skip redundant raid_disks update when value is unchanged
dm-raid: only requeue bios when dm is suspending
MAINTAINERS: Update Li Nan's E-mail address
MAINTAINERS: update Yu Kuai's email address
In raid1_write_request(), each per-mirror loop iteration begins by
incrementing rdev->nr_pending. If a REQ_ATOMIC write encounters a
badblock within the requested range, the code jumps to err_handle
without dropping the reference taken for the current mirror.
err_handle's cleanup loop will only decrements for k < i and
r1_bio->bios[k] is non-NULL. The current slot is therefore skipped,
leaving its nr_pending reference leaked permanently. The reference
prevents the rdev from ever being removed, since raid1_remove_conf()
refuses to remove an rdev with nr_pending > 0.
Fix this by calling rdev_dec_pending() before jumping to err_handle.
Fixes: f2a38abf5f ("md/raid1: Atomic write support")
Signed-off-by: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com>
Link: https://patch.msgid.link/20260530151411.4119-1-abd.masalkhi@gmail.com
Signed-off-by: Yu Kuai <yukuai@fygo.io>
Use md_cloned_bio() to control bio accounting instead of relying
on r1bio_existed in raid1 or the io_accounting flag in raid10.
The previous logic does not reliably reflect whether a bio is an
md cloned bio. When a failed bio is split and resubmitted via
bio_submit_split_bioset() on the error path, this can lead to either
double accounting for md cloned bios, or missing accounting for bios
returned from bio_submit_split_bioset()
Fix this by using md_cloned_bio() to detect md cloned bios and
skip accounting accordingly.
Fixes: bb2a9acefa ("md/raid1: switch to use md_account_bio() for io accounting")
Fixes: 8204552383 ("md/raid10: switch to use md_account_bio() for io accounting")
Signed-off-by: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com>
Reviewed-by: Xiao Ni <xiao@kernel.org>
Link: https://patch.msgid.link/20260501114652.590037-4-abd.masalkhi@gmail.com
Signed-off-by: Yu Kuai <yukuai@fygo.io>
Detect the error path using md_cloned_bio() instead of relying
on r1_bio in raid1 or r10_bio->read_slot in raid10, which may be
NULL or -1 after splitting and resubmitting a failed bio.
As a result, the error path may not be recognized and memory
allocations can incorrectly use GFP_NOIO instead of
(GFP_NOIO | __GFP_HIGH), which can lead to a deadlock under
memory pressure.
Fixes: 689389a06c ("md/raid1: simplify handle_read_error().")
Fixes: 545250f248 ("md/raid10: simplify handle_read_error()")
Signed-off-by: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com>
Reviewed-by: Xiao Ni <xiao@kernel.org>
Link: https://patch.msgid.link/20260501114652.590037-3-abd.masalkhi@gmail.com
Signed-off-by: Yu Kuai <yukuai@fygo.io>
MD RAID does not propagate BLK_FEAT_PCI_P2PDMA from member devices to
the RAID device, preventing peer-to-peer DMA through the RAID layer even
when all underlying devices support it.
Enable BLK_FEAT_PCI_P2PDMA unconditionally in raid0, raid1 and raid10
personalities during queue limits setup. blk_stack_limits() clears it
automatically if any member device lacks support, consistent with how
BLK_FEAT_NOWAIT and BLK_FEAT_POLL are handled in the block core.
Parity RAID personalities (raid4/5/6) are excluded because they require
CPU access to data pages for parity computation, which is incompatible
with P2P mappings.
Tested with RAID0/1/10 arrays containing multiple NVMe devices with
P2PDMA support, confirming that peer-to-peer transfers work correctly
through the RAID layer.
Tested-by: Pranjal Shrivastava <praan@google.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Sagi Grimberg <sagi@grimberg.me>
Reviewed-by: Xiao Ni <xni@redhat.com>
Signed-off-by: Kiran Kumar Modukuri <kmodukuri@nvidia.com>
Signed-off-by: Chaitanya Kulkarni <kch@nvidia.com>
Reviewed-by: Yu Kuai <yukuai@fygo.io>
Tested=by: Pranjal Shrivastava <praan@google.com>
Link: https://patch.msgid.link/20260513185153.95552-3-kch@nvidia.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Previously, using wait_event() would wake up all waiters simultaneously,
and they would compete for the tree lock. The bio which gets the lock
first will be handled, so the write sequence cannot be guaranteed.
For example:
bio1(100,200)
bio2(150,200)
bio3(150,300)
The write sequence of fast device is bio1,bio2,bio3. But the write sequence
of slow device could be bio1,bio3,bio2 due to lock competition. This causes
data corruption.
Replace waitqueue with a fifo list to guarantee the write sequence. And it
also needs to iterate the list when removing one entry. If not, it may miss
the opportunity to wake up the waiting io.
For example:
bio1(1,3), bio2(2,4)
bio3(5,7), bio4(6,8)
These four bios are in the same bucket. bio1 and bio3 are inserted into
the rbtree. bio2 and bio4 are added to the waiting list and bio2 is the
first one. bio3 returns from slow disk and tries to wake up the waiting
bios. bio2 is removed from the list and will be handled. But bio1 hasn't
finished. So bio2 will be added into waiting list again. Then bio1 returns
from slow disk and wakes up waiting bios. bio4 is removed from the list
and will be handled. Now bio1, bio3 and bio4 all finish and bio2 is left
on the waiting list. So it needs to iterate the waiting list to wake up
the right bio.
Signed-off-by: Xiao Ni <xni@redhat.com>
Link: https://lore.kernel.org/linux-raid/20260324072501.59865-1-xni@redhat.com/
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
Interval tree uses [start, end] as a region which stores in the tree.
In raid1, it uses the wrong end value. For example:
bio(A,B) is too big and needs to be split to bio1(A,C-1), bio2(C,B).
The region of bio1 is [A,C] and the region of bio2 is [C,B]. So bio1 and
bio2 overlap which is not right.
Fix this problem by using right end value of the region.
Fixes: d0d2d8ba04 ("md/raid1: introduce wait_for_serialization")
Signed-off-by: Xiao Ni <xni@redhat.com>
Link: https://lore.kernel.org/linux-raid/20260305011839.5118-2-xni@redhat.com/
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
bdev_nonrot() is simply the negative return value of bdev_rot().
So replace all call sites of bdev_nonrot() with calls to bdev_rot()
and remove bdev_nonrot().
Signed-off-by: Damien Le Moal <dlemoal@kernel.org>
Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com>
Reviewed-by: Paul Menzel <pmenzel@molgen.mpg.de>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This converts some of the visually simpler cases that have been split
over multiple lines. I only did the ones that are easy to verify the
resulting diff by having just that final GFP_KERNEL argument on the next
line.
Somebody should probably do a proper coccinelle script for this, but for
me the trivial script actually resulted in an assertion failure in the
middle of the script. I probably had made it a bit _too_ trivial.
So after fighting that far a while I decided to just do some of the
syntactically simpler cases with variations of the previous 'sed'
scripts.
The more syntactically complex multi-line cases would mostly really want
whitespace cleanup anyway.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This was done entirely with mindless brute force, using
git grep -l '\<k[vmz]*alloc_objs*(.*, GFP_KERNEL)' |
xargs sed -i 's/\(alloc_objs*(.*\), GFP_KERNEL)/\1)/'
to convert the new alloc_obj() users that had a simple GFP_KERNEL
argument to just drop that argument.
Note that due to the extreme simplicity of the scripting, any slightly
more complex cases spread over multiple lines would not be triggered:
they definitely exist, but this covers the vast bulk of the cases, and
the resulting diff is also then easier to check automatically.
For the same reason the 'flex' versions will be done as a separate
conversion.
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This is the result of running the Coccinelle script from
scripts/coccinelle/api/kmalloc_objs.cocci. The script is designed to
avoid scalar types (which need careful case-by-case checking), and
instead replace kmalloc-family calls that allocate struct or union
object instances:
Single allocations: kmalloc(sizeof(TYPE), ...)
are replaced with: kmalloc_obj(TYPE, ...)
Array allocations: kmalloc_array(COUNT, sizeof(TYPE), ...)
are replaced with: kmalloc_objs(TYPE, COUNT, ...)
Flex array allocations: kmalloc(struct_size(PTR, FAM, COUNT), ...)
are replaced with: kmalloc_flex(*PTR, FAM, COUNT, ...)
(where TYPE may also be *VAR)
The resulting allocations no longer return "void *", instead returning
"TYPE *".
Signed-off-by: Kees Cook <kees@kernel.org>
raid1_run() calls setup_conf() which registers a thread via
md_register_thread(). If raid1_set_limits() fails, the previously
registered thread is not unregistered, resulting in a memory leak
of the md_thread structure and the thread resource itself.
Add md_unregister_thread() to the error path to properly cleanup
the thread, which aligns with the error handling logic of other paths
in this function.
Compile tested only. Issue found using a prototype static analysis tool
and code review.
Link: https://lore.kernel.org/linux-raid/20260126071533.606263-1-zilin@seu.edu.cn
Fixes: 97894f7d3c ("md/raid1: use the atomic queue limit update APIs")
Signed-off-by: Zilin Guan <zilin@seu.edu.cn>
Reviewed-by: Li Nan <linan122@huawei.com>
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
'recovery_disabled' logic is complex and confusing, originally intended to
preserve raid in extreme scenarios. It was used in following cases:
- When sync fails and setting badblocks also fails, kick out non-In_sync
rdev and block spare rdev from joining to preserve raid [1]
- When last backup is unavailable, prevent repeated add-remove of spares
triggering recovery [2]
The original issues are now resolved:
- Error handlers in all raid types prevent last rdev from being kicked out
- Disks with failed recovery are marked Faulty and can't re-join
Therefore, remove 'recovery_disabled' as it's no longer needed.
[1] 5389042ffa ("md: change managed of recovery_disabled.")
[2] 4044ba58dd ("md: don't retry recovery of raid1 that fails due to error on source drive.")
Link: https://lore.kernel.org/linux-raid/20260105110300.1442509-13-linan666@huaweicloud.com
Signed-off-by: Li Nan <linan122@huawei.com>
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
Currently when sync read fails and badblocks set fails (exceeding
512 limit), rdev isn't immediately marked Faulty. Instead
'recovery_disabled' is set and non-In_sync rdevs are removed later.
This preserves array availability if bad regions aren't read, but bad
sectors might be read by users before rdev removal. This occurs due
to incorrect resync/recovery_offset updates that include these bad
sectors.
When badblocks exceed 512, keeping the disk provides little benefit
while adding complexity. Prompt disk replacement is more important.
Therefore when badblocks set fails, directly call md_error to mark rdev
Faulty immediately, preventing potential data access issues.
After this change, cleanup of offset update logic and 'recovery_disabled'
handling will follow.
Link: https://lore.kernel.org/linux-raid/20260105110300.1442509-6-linan666@huaweicloud.com
Fixes: 5e5702898e ("md/raid10: Handle read errors during recovery better.")
Fixes: 3a9f28a511 ("md/raid1: improve handling of read failure during recovery.")
Signed-off-by: Li Nan <linan122@huawei.com>
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
When badblocks.shift < 0 (badblocks disabled), narrow_write_error()
return false, preventing write error handling. Since narrow_write_error()
only splits IO into smaller sizes and re-submits, it can work with
badblocks disabled.
Adjust to use the logical block size for block_sectors when badblocks is
disabled, allowing narrow_write_error() to function in this case.
Link: https://lore.kernel.org/linux-raid/20260105110300.1442509-4-linan666@huaweicloud.com
Signed-off-by: Li Nan <linan122@huawei.com>
Reviewed-by: Yu Kuai <yukuai@fnnas.com>
Signed-off-by: Yu Kuai <yukuai@fnnas.com>
Chen Cheng
Abd-Alrhman Masalkhi
Jens Axboe
Christoph Hellwig
Kiran Kumar Modukuri
Xiao Ni
Damien Le Moal
Linus Torvalds
Kees Cook
Zilin Guan
Li Nan