From: Yu Kuai <yukuai@fygo.io> stable inclusion from stable-v6.6.157 commit 9d7490007707f90691911385365bd1d691d99225 category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/19461 CVE: CVE-2026-90279 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ Upstream commit 17ea021ae74987d6064c8195c4922fa025753892 ] raid5_bitmap_sector_map() aligns the array range to full RAID5 stripe widths before converting it to component sectors. That width is chunk_sectors multiplied by the number of data disks, and it is not always a power of two. Reproduce with a 4-disk RAID5, 1024-sector chunks, and three data disks. The full-stripe width is 3072 sectors. For a one-sector write at array sector 3072, correct rounding gives array range [3072, 6144), which maps to component range [1024, 2048). The old round_down()/round_up() logic instead gives [1024, 4096), which maps to [0, 1024). Use sector_div() based arithmetic so the rounded range is aligned to the actual RAID5 stripe width. The deterministic mapper test now reports the fixed component range as [1024, 2048), while the old mask-based range was [0, 1024). Fixes: 9c89f604476c ("md/raid5: implement pers->bitmap_sector()") Reported-by: Mykola Marzhan <mykola@meshstor.io> Link: https://lore.kernel.org/all/20260726185916.2223460-1-mykola@meshstor.io/ Tested-by: Mykola Marzhan <mykola@meshstor.io> Link: https://patch.msgid.link/20260802195038.164272-6-yukuai@kernel.org Signed-off-by: Yu Kuai <yukuai@fygo.io> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Lu Jialin <lujialin4@huawei.com> --- drivers/md/raid5.c | 13 +++++++++---- 1 file changed, 9 insertions(+), 4 deletions(-) diff --git a/drivers/md/raid5.c b/drivers/md/raid5.c index 6ec8e1b3d8b2..435612b60c53 100644 --- a/drivers/md/raid5.c +++ b/drivers/md/raid5.c @@ -5899,8 +5899,11 @@ static void raid5_bitmap_sector(struct mddev *mddev, sector_t *offset, sectors_per_chunk = conf->chunk_sectors * (conf->raid_disks - conf->max_degraded); - start = round_down(start, sectors_per_chunk); - end = round_up(end, sectors_per_chunk); + sector_div(start, sectors_per_chunk); + start *= sectors_per_chunk; + if (sector_div(end, sectors_per_chunk)) + end++; + end *= sectors_per_chunk; start = raid5_compute_sector(conf, start, 0, &dd_idx, NULL); end = raid5_compute_sector(conf, end, 0, &dd_idx, NULL); @@ -5918,8 +5921,10 @@ static void raid5_bitmap_sector(struct mddev *mddev, sector_t *offset, sectors_per_chunk = conf->prev_chunk_sectors * (conf->previous_raid_disks - conf->max_degraded); - prev_start = round_down(prev_start, sectors_per_chunk); - prev_end = round_down(prev_end, sectors_per_chunk); + sector_div(prev_start, sectors_per_chunk); + prev_start *= sectors_per_chunk; + sector_div(prev_end, sectors_per_chunk); + prev_end *= sectors_per_chunk; prev_start = raid5_compute_sector(conf, prev_start, 1, &dd_idx, NULL); prev_end = raid5_compute_sector(conf, prev_end, 1, &dd_idx, NULL); -- 2.34.1