kernel/linux.git/drivers/md/raid10.c, branch v5.15.209

md/raid10: fix divide-by-zero in setup_geo() with zero far_copies

2026-06-01T15:35:23+00:00

commit 9aa6d860b0930e2f72795665c42c44252a558a0c upstream. setup_geo() extracts near_copies (nc) and far_copies (fc) from the user-provided layout parameter without checking for zero. When fc=0 with the "improved" far set layout selected, 'geo->far_set_size = disks / fc' triggers a divide-by-zero. Validate nc and fc immediately after extraction, returning -1 if either is zero. Fixes: 475901aff158 ("MD RAID10: Improve redundancy for 'far' and 'offset' algorithms (part 1)") Cc: stable@vger.kernel.org Signed-off-by: Junrui Luo Link: https://lore.kernel.org/linux-raid/SYBPR01MB7881A5E2556806CC1D318582AF232@SYBPR01MB7881.ausprd01.prod.outlook.com Signed-off-by: Yu Kuai Signed-off-by: Greg Kroah-Hartman

md/raid10: fix deadlock with check operation and nowait requests

2026-06-01T15:35:15+00:00

commit 7d96f3120a7fb7210d21b520c5b6f495da6ba436 upstream. When an array check is running it will raise the barrier at which point normal requests will become blocked and increment the nr_pending value to signal there is work pending inside of wait_barrier(). NOWAIT requests do not block and so will return immediately with an error, and additionally do not increment nr_pending in wait_barrier(). Upstream change commit 43806c3d5b9b ("raid10: cleanup memleak at raid10_make_request") added a call to raid_end_bio_io() to fix a memory leak when NOWAIT requests hit this condition. raid_end_bio_io() eventually calls allow_barrier() and it will unconditionally do an atomic_dec_and_test(&conf->nr_pending) even though the corresponding increment on nr_pending didn't happen in the NOWAIT case. This can be easily seen by starting a check operation while an application is doing nowait IO on the same array. This results in a deadlocked state due to nr_pending value underflowing and so the md resync thread gets stuck waiting for nr_pending to == 0. Output of r10conf state of the array when we hit this condition: crash> struct r10conf barrier = 1, nr_pending = { counter = -41 }, nr_waiting = 15, nr_queued = 0, Example of md_sync thread stuck waiting on raise_barrier() and other requests stuck in wait_barrier(): md1_resync [<0>] raise_barrier+0xce/0x1c0 [<0>] raid10_sync_request+0x1ca/0x1ed0 [<0>] md_do_sync+0x779/0x1110 [<0>] md_thread+0x90/0x160 [<0>] kthread+0xbe/0xf0 [<0>] ret_from_fork+0x34/0x50 [<0>] ret_from_fork_asm+0x1a/0x30 kworker/u1040:2+flush-253:4 [<0>] wait_barrier+0x1de/0x220 [<0>] regular_request_wait+0x30/0x180 [<0>] raid10_make_request+0x261/0x1000 [<0>] md_handle_request+0x13b/0x230 [<0>] __submit_bio+0x107/0x1f0 [<0>] submit_bio_noacct_nocheck+0x16f/0x390 [<0>] ext4_io_submit+0x24/0x40 [<0>] ext4_do_writepages+0x254/0xc80 [<0>] ext4_writepages+0x84/0x120 [<0>] do_writepages+0x7a/0x260 [<0>] __writeback_single_inode+0x3d/0x300 [<0>] writeback_sb_inodes+0x1dd/0x470 [<0>] __writeback_inodes_wb+0x4c/0xe0 [<0>] wb_writeback+0x18b/0x2d0 [<0>] wb_workfn+0x2a1/0x400 [<0>] process_one_work+0x149/0x330 [<0>] worker_thread+0x2d2/0x410 [<0>] kthread+0xbe/0xf0 [<0>] ret_from_fork+0x34/0x50 [<0>] ret_from_fork_asm+0x1a/0x30 Fixes: 43806c3d5b9b ("raid10: cleanup memleak at raid10_make_request") Cc: stable@vger.kernel.org Signed-off-by: Josh Hunt Link: https://lore.kernel.org/linux-raid/20260303005619.1352958-1-johunt@akamai.com Signed-off-by: Yu Kuai Signed-off-by: Greg Kroah-Hartman

md/raid10: fix any_working flag handling in raid10_sync_request

2026-03-04T12:19:22+00:00

[ Upstream commit 99582edb3f62e8ee6c34512021368f53f9b091f2 ] In raid10_sync_request(), 'any_working' indicates if any IO will be submitted. When there's only one In_sync disk with badblocks, 'any_working' might be set to 1 but no IO is submitted. Fix it by setting 'any_working' after badblock checks. Link: https://lore.kernel.org/linux-raid/20260105110300.1442509-11-linan666@huaweicloud.com Fixes: e875ecea266a ("md/raid10 record bad blocks as needed during recovery.") Signed-off-by: Li Nan Reviewed-by: Yu Kuai Signed-off-by: Yu Kuai Signed-off-by: Sasha Levin

raid10: cleanup memleak at raid10_make_request

2025-07-17T16:30:52+00:00

[ Upstream commit 43806c3d5b9bb7d74ba4e33a6a8a41ac988bde24 ] If raid10_read_request or raid10_write_request registers a new request and the REQ_NOWAIT flag is set, the code does not free the malloc from the mempool. unreferenced object 0xffff8884802c3200 (size 192): comm "fio", pid 9197, jiffies 4298078271 hex dump (first 32 bytes): 00 00 00 00 00 00 00 00 88 41 02 00 00 00 00 00 .........A...... 08 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace (crc c1a049a2): __kmalloc+0x2bb/0x450 mempool_alloc+0x11b/0x320 raid10_make_request+0x19e/0x650 [raid10] md_handle_request+0x3b3/0x9e0 __submit_bio+0x394/0x560 __submit_bio_noacct+0x145/0x530 submit_bio_noacct_nocheck+0x682/0x830 __blkdev_direct_IO_async+0x4dc/0x6b0 blkdev_read_iter+0x1e5/0x3b0 __io_read+0x230/0x1110 io_read+0x13/0x30 io_issue_sqe+0x134/0x1180 io_submit_sqes+0x48c/0xe90 __do_sys_io_uring_enter+0x574/0x8b0 do_syscall_64+0x5c/0xe0 entry_SYSCALL_64_after_hwframe+0x76/0x7e V4: changing backing tree to see if CKI tests will pass. The patch code has not changed between any versions. Fixes: c9aa889b035f ("md: raid10 add nowait support") Signed-off-by: Nigel Croxon Link: https://lore.kernel.org/linux-raid/c0787379-9caa-42f3-b5fc-369aed784400@redhat.com Signed-off-by: Yu Kuai Signed-off-by: Sasha Levin

md/raid10: fix missing discard IO accounting

2025-05-02T05:44:08+00:00

[ Upstream commit d05af90d6218e9c8f1c2026990c3f53c1b41bfb0 ] md_account_bio() is not called from raid10_handle_discard(), now that we handle bitmap inside md_account_bio(), also fix missing bitmap_startwrite for discard. Test whole disk discard for 20G raid10: Before: Device d/s dMB/s drqm/s %drqm d_await dareq-sz md0 48.00 16.00 0.00 0.00 5.42 341.33 After: Device d/s dMB/s drqm/s %drqm d_await dareq-sz md0 68.00 20462.00 0.00 0.00 2.65 308133.65 Link: https://lore.kernel.org/linux-raid/20250325015746.3195035-1-yukuai1@huaweicloud.com Fixes: 528bc2cf2fcc ("md/raid10: enable io accounting") Signed-off-by: Yu Kuai Acked-by: Coly Li Signed-off-by: Sasha Levin

md/raid10: improve code of mrdev in raid10_sync_request

2024-11-17T14:06:25+00:00

commit 59f8f0b54c8ffb4521f6bbd1cb6f4dfa5022e75e upstream. 'need_recover' and 'mrdev' are equivalent in raid10_sync_request(), and inc mrdev->nr_pending is unreasonable if don't need recovery. Replace 'need_recover' with 'mrdev', and only inc nr_pending when needed. Signed-off-by: Li Nan Reviewed-by: Yu Kuai Signed-off-by: Song Liu Link: https://lore.kernel.org/r/20230527072218.2365857-3-linan666@huaweicloud.com Cc: Hagar Gamal Halim Signed-off-by: Greg Kroah-Hartman

md/raid10: prevent soft lockup while flush writes

2024-03-01T12:21:55+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: Set MD_BROKEN for RAID1 and RAID10

2023-09-19T10:22:39+00:00

[ Upstream commit 9631abdbf406c764f2a5d8305eac063bc3396a0a ] There is no direct mechanism to determine raid failure outside personality. It is done by checking rdev->flags after executing md_error(). If "faulty" flag is not set then -EBUSY is returned to userspace. -EBUSY means that array will be failed after drive removal. Mdadm has special routine to handle the array failure and it is executed if -EBUSY is returned by md. There are at least two known reasons to not consider this mechanism as correct: 1. drive can be removed even if array will be failed[1]. 2. -EBUSY seems to be wrong status. Array is not busy, but removal process cannot proceed safe. -EBUSY expectation cannot be removed without breaking compatibility with userspace. In this patch first issue is resolved by adding support for MD_BROKEN flag for RAID1 and RAID10. Support for RAID456 is added in next commit. The idea is to set the MD_BROKEN if we are sure that raid is in failed state now. This is done in each error_handler(). In md_error() MD_BROKEN flag is checked. If is set, then -EBUSY is returned to userspace. As in previous commit, it causes that #mdadm --set-faulty is able to fail array. Previously proposed workaround is valid if optional functionality[1] is disabled. [1] commit 9a567843f7ce("md: allow last device to be forcibly removed from RAID1/RAID10.") Reviewd-by: Xiao Ni Signed-off-by: Mariusz Tkaczyk Signed-off-by: Song Liu Stable-dep-of: 319ff40a5427 ("md/raid0: Fix performance regression for large sequential writes") Signed-off-by: Sasha Levin

md/raid10: use dereference_rdev_and_rrdev() to get devices

2023-09-19T10:22:38+00:00

[ Upstream commit 673643490b9a0eb3b25633abe604f62b8f63dba1 ] Commit 2ae6aaf76912 ("md/raid10: fix io loss while replacement replace rdev") reads replacement first to prevent io loss. However, there are same issue in wait_blocked_dev() and raid10_handle_discard(), too. Fix it by using dereference_rdev_and_rrdev() to get devices. Fixes: d30588b2731f ("md/raid10: improve raid10 discard request") Fixes: f2e7e269a752 ("md/raid10: pull the code that wait for blocked dev into one function") Signed-off-by: Li Nan Link: https://lore.kernel.org/r/20230701080529.2684932-4-linan666@huaweicloud.com Signed-off-by: Song Liu Signed-off-by: Sasha Levin

md/raid10: factor out dereference_rdev_and_rrdev()

2023-09-19T10:22:38+00:00

[ Upstream commit b99f8fd2d91eb734f13098aa1cf337edaca454b7 ] Factor out a helper to get 'rdev' and 'replacement' from config->mirrors. Just to make code cleaner and prepare to fix the bug of io loss while 'replacement' replace 'rdev'. There is no functional change. Signed-off-by: Li Nan Link: https://lore.kernel.org/r/20230701080529.2684932-3-linan666@huaweicloud.com Signed-off-by: Song Liu Stable-dep-of: 673643490b9a ("md/raid10: use dereference_rdev_and_rrdev() to get devices") Signed-off-by: Sasha Levin