From: FengWei Shih Date: Fri, 26 Dec 2025 10:18:16 +0000 (+0800) Subject: md: suspend array while updating raid_disks via sysfs X-Git-Tag: v6.19-rc4~8^2~1^2~2 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2cc583653bbe050bacd1cadcc9776d39bf449740;p=thirdparty%2Flinux.git md: suspend array while updating raid_disks via sysfs In raid1_reshape(), freeze_array() is called before modifying the r1bio memory pool (conf->r1bio_pool) and conf->raid_disks, and unfreeze_array() is called after the update is completed. However, freeze_array() only waits until nr_sync_pending and (nr_pending - nr_queued) of all buckets reaches zero. When an I/O error occurs, nr_queued is increased and the corresponding r1bio is queued to either retry_list or bio_end_io_list. As a result, freeze_array() may unblock before these r1bios are released. This can lead to a situation where conf->raid_disks and the mempool have already been updated while queued r1bios, allocated with the old raid_disks value, are later released. Consequently, free_r1bio() may access memory out of bounds in put_all_bios() and release r1bios of the wrong size to the new mempool, potentially causing issues with the mempool as well. Since only normal I/O might increase nr_queued while an I/O error occurs, suspending the array avoids this issue. Note: Updating raid_disks via ioctl SET_ARRAY_INFO already suspends the array. Therefore, we suspend the array when updating raid_disks via sysfs to avoid this issue too. Signed-off-by: FengWei Shih Link: https://lore.kernel.org/linux-raid/20251226101816.4506-1-dannyshih@synology.com Signed-off-by: Yu Kuai --- diff --git a/drivers/md/md.c b/drivers/md/md.c index 03433c88fb54..dda272e87a1b 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c @@ -4404,7 +4404,7 @@ raid_disks_store(struct mddev *mddev, const char *buf, size_t len) if (err < 0) return err; - err = mddev_lock(mddev); + err = mddev_suspend_and_lock(mddev); if (err) return err; if (mddev->pers) @@ -4429,7 +4429,7 @@ raid_disks_store(struct mddev *mddev, const char *buf, size_t len) } else mddev->raid_disks = n; out_unlock: - mddev_unlock(mddev); + mddev_unlock_and_resume(mddev); return err ? err : len; } static struct md_sysfs_entry md_raid_disks =