From nobody Tue Jun 9 00:49:57 2026 Received: from va-2-26.ptr.blmpb.com (va-2-26.ptr.blmpb.com [209.127.231.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id C7290267B89 for ; Mon, 25 May 2026 01:55:47 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.127.231.26 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779674150; cv=none; b=jFpIjrNMk3UjbOh/iOJ1tM+18c198sQGOn26VXR45srZSh+FmbiX5KMdf3LRhrb8Ap3yUBccrb6zt9aeHx35YZvWXAHWU0pzRzWAj8zeIP6E22e4Epu3RYxgPzDsTbLU/O3GPqZinVhD7voX96MNH1KtyR5ap2ZaVCl/k7plOIw= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779674150; c=relaxed/simple; bh=j+P5RR25TjpmzCOmqCmil0swp/wB7oytipMPUcGp+/g=; h=Cc:Date:Mime-Version:Content-Type:To:From:Subject:Message-Id: References:In-Reply-To; b=unG2zVIkOJ5y4mTrt/6uATtT0kQNx83VUk1jSZyQED5d3a+9j/dIqhm4cHqAtt/jvyA9lYMvAee5N74P1yGdOtPfAJQMvD7icRC6t72aURL4aSPMWJSe2H0RKdncCGblCFgLVQADNuQhXynFNfg3On5d16Nvl254KjUMFLNcvSA= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=fnnas.com; spf=pass smtp.mailfrom=fnnas.com; dkim=pass (2048-bit key) header.d=fnnas-com.20200927.dkim.feishu.cn header.i=@fnnas-com.20200927.dkim.feishu.cn header.b=XaIk+TaX; arc=none smtp.client-ip=209.127.231.26 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=fnnas.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fnnas.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fnnas-com.20200927.dkim.feishu.cn header.i=@fnnas-com.20200927.dkim.feishu.cn header.b="XaIk+TaX" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; s=s1; d=fnnas-com.20200927.dkim.feishu.cn; t=1779674137; h=from:subject:mime-version:from:date:message-id:subject:to:cc: reply-to:content-type:mime-version:in-reply-to:message-id; bh=+smOMbNrxZJFkl+/dG8EeZBhxjYpYu0uEADK96Q6rG4=; b=XaIk+TaXxfNJad2qPTVIssAm4RM3bRmFYxzelHjoi8eBoURI3sRepx2stldcaN0sHC+0Mw xTscU/JSulimAevfqIQR6U9UlxDRiykE+6/Z1wF/08QqYybROi5IRIFoaCJp7kNxVFGfRD u4o2r/Tpj1rD1AI97RqmYpNCcGb5S5GbB+jK50KnDhE1Tn6tcmKnZPcC1jCrEjDVnyeh0l ib1NaGHILUd3RGWoofZPlBnVxtGPLrSmApjXXdB9gCaWuurBJ8c/c6FTUVWjrPTJ9p2K6e 5GYnIq1CGJ+F4VcngVzkdEvikN3eP8jDDBBw1ZG2eRCExkfle9P7XJPHEzE03w== Cc: "Chen Cheng" , Date: Mon, 25 May 2026 09:55:19 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Original-From: chencheng@fnnas.com Content-Transfer-Encoding: quoted-printable To: "Yu Kuai" , From: "Chen Cheng" Subject: [PATCH v3 1/2] md/raid10: make r10bio_pool use fixed-size objects Message-Id: <20260525015520.2565423-2-chencheng@fnnas.com> References: <20260525015520.2565423-1-chencheng@fnnas.com> X-Lms-Return-Path: In-Reply-To: <20260525015520.2565423-1-chencheng@fnnas.com> X-Mailer: git-send-email 2.54.0 Received: from localhost.localdomain ([113.111.141.72]) by smtp.feishu.cn with ESMTPS; Mon, 25 May 2026 09:55:34 +0800 Content-Type: text/plain; charset="utf-8" From: Chen Cheng raid10 currently allocates r10bio_pool objects with conf->geo.raid_disks, which makes regular r10bio objects geometry-dependent. That model breaks down across reshape. mempool objects are preallocated and reused, so a reshape that changes the number of raid disks can leave old r10bio objects in the regular I/O pool with a devs[] array sized for the previous geometry. After the geometry switch, those stale objects may be reused or later freed under the new layout, creating a width mismatch between the reused r10bio and the current array geometry. For example, during a 4-disk to 5-disk reshape, an r10bio allocated before the geometry switch has room for only 4 devs[] entries. After reshape updates conf->geo.raid_disks to 5, that stale object can be reused under the new geometry. Code such as __make_request(), put_all_bios(), and find_bio_disk() may then access devs[] using the new geometry and step past the end of the old 4-slot object, leading to slab out-of-bounds accesses. The root problem is that regular r10bio pool objects are geometry-dependent, while mempool elements are preallocated and reused across requests. Switch r10bio_pool to a fixed-size kmalloc mempool so regular I/O objects no longer carry an allocation width tied to the current geometry. Use the same fixed-size allocation rule for the standalone r10bio allocated from r10buf_pool_alloc(). Signed-off-by: Chen Cheng --- drivers/md/raid10.c | 57 ++++++++++++++++++++++++++++++++++----------- drivers/md/raid10.h | 2 +- 2 files changed, 45 insertions(+), 14 deletions(-) diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 39085e7dd6d2..64677dbe5152 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -101,17 +101,32 @@ static void end_reshape(struct r10conf *conf); static inline struct r10bio *get_resync_r10bio(struct bio *bio) { return get_resync_pages(bio)->raid_bio; } =20 -static void * r10bio_pool_alloc(gfp_t gfp_flags, void *data) +static inline unsigned int calc_r10bio_pool_disks(struct mddev *mddev) { - struct r10conf *conf =3D data; - int size =3D offsetof(struct r10bio, devs[conf->geo.raid_disks]); + /* If delta_disks < 0, use bigger r10bio->devs[] is ok. */ + return mddev->raid_disks + max(0, mddev->delta_disks); +} + +static inline int calc_r10bio_size(struct mddev *mddev) +{ + return offsetof(struct r10bio, devs[calc_r10bio_pool_disks(mddev)]); +} + +static mempool_t *create_r10bio_pool(struct mddev *mddev) +{ + int size =3D calc_r10bio_size(mddev); + + return mempool_create_kmalloc_pool(NR_RAID_BIOS, size); +} + +static struct r10bio *alloc_r10bio(struct mddev *mddev, gfp_t gfp_flags) +{ + int size =3D calc_r10bio_size(mddev); =20 - /* allocate a r10bio with room for raid_disks entries in the - * bios array */ return kzalloc(size, gfp_flags); } =20 #define RESYNC_SECTORS (RESYNC_BLOCK_SIZE >> 9) /* amount of memory to reserve for resync requests */ @@ -135,11 +150,11 @@ static void * r10buf_pool_alloc(gfp_t gfp_flags, void= *data) struct bio *bio; int j; int nalloc, nalloc_rp; struct resync_pages *rps; =20 - r10_bio =3D r10bio_pool_alloc(gfp_flags, conf); + r10_bio =3D alloc_r10bio(conf->mddev, gfp_flags); if (!r10_bio) return NULL; =20 if (test_bit(MD_RECOVERY_SYNC, &conf->mddev->recovery) || test_bit(MD_RECOVERY_RESHAPE, &conf->mddev->recovery)) @@ -275,11 +290,11 @@ static void put_all_bios(struct r10conf *conf, struct= r10bio *r10_bio) static void free_r10bio(struct r10bio *r10_bio) { struct r10conf *conf =3D r10_bio->mddev->private; =20 put_all_bios(conf, r10_bio); - mempool_free(r10_bio, &conf->r10bio_pool); + mempool_free(r10_bio, conf->r10bio_pool); } =20 static void put_buf(struct r10bio *r10_bio) { struct r10conf *conf =3D r10_bio->mddev->private; @@ -1529,11 +1544,11 @@ static void raid10_write_request(struct mddev *mdde= v, struct bio *bio, static void __make_request(struct mddev *mddev, struct bio *bio, int secto= rs) { struct r10conf *conf =3D mddev->private; struct r10bio *r10_bio; =20 - r10_bio =3D mempool_alloc(&conf->r10bio_pool, GFP_NOIO); + r10_bio =3D mempool_alloc(conf->r10bio_pool, GFP_NOIO); =20 r10_bio->master_bio =3D bio; r10_bio->sectors =3D sectors; =20 r10_bio->mddev =3D mddev; @@ -1721,11 +1736,11 @@ static int raid10_handle_discard(struct mddev *mdde= v, struct bio *bio) last_stripe_index *=3D geo->far_copies; end_disk_offset =3D (bio_end & geo->chunk_mask) + (last_stripe_index << geo->chunk_shift); =20 retry_discard: - r10_bio =3D mempool_alloc(&conf->r10bio_pool, GFP_NOIO); + r10_bio =3D mempool_alloc(conf->r10bio_pool, GFP_NOIO); r10_bio->mddev =3D mddev; r10_bio->state =3D 0; r10_bio->sectors =3D 0; memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * geo->raid_disks); wait_blocked_dev(mddev, r10_bio); @@ -3821,11 +3836,11 @@ static int setup_geo(struct geom *geo, struct mddev= *mddev, enum geo_type new) static void raid10_free_conf(struct r10conf *conf) { if (!conf) return; =20 - mempool_exit(&conf->r10bio_pool); + mempool_destroy(conf->r10bio_pool); kfree(conf->mirrors); kfree(conf->mirrors_old); kfree(conf->mirrors_new); safe_put_page(conf->tmppage); bioset_exit(&conf->bio_split); @@ -3868,13 +3883,12 @@ static struct r10conf *setup_conf(struct mddev *mdd= ev) if (!conf->tmppage) goto out; =20 conf->geo =3D geo; conf->copies =3D copies; - err =3D mempool_init(&conf->r10bio_pool, NR_RAID_BIOS, r10bio_pool_alloc, - rbio_pool_free, conf); - if (err) + conf->r10bio_pool =3D create_r10bio_pool(mddev); + if (!conf->r10bio_pool) goto out; =20 err =3D bioset_init(&conf->bio_split, BIO_POOL_SIZE, 0, 0); if (err) goto out; @@ -4363,10 +4377,11 @@ static int raid10_start_reshape(struct mddev *mddev) struct geom new; struct r10conf *conf =3D mddev->private; struct md_rdev *rdev; int spares =3D 0; int ret; + mempool_t *new_pool; =20 if (test_bit(MD_RECOVERY_RUNNING, &mddev->recovery)) return -EBUSY; =20 if (setup_geo(&new, mddev, geo_start) !=3D conf->copies) @@ -4398,11 +4413,23 @@ static int raid10_start_reshape(struct mddev *mddev) return -EINVAL; =20 if (spares < mddev->delta_disks) return -EINVAL; =20 + mddev_unlock(mddev); + mddev_suspend_and_lock_nointr(mddev); conf->offset_diff =3D min_offset_diff; + if (mddev->delta_disks > 0) { + new_pool =3D create_r10bio_pool(mddev); + if (!new_pool) { + mddev_unlock_and_resume(mddev); + mddev_lock_nointr(mddev); + return -ENOMEM; + } + mempool_destroy(conf->r10bio_pool); + conf->r10bio_pool =3D new_pool; + } spin_lock_irq(&conf->device_lock); if (conf->mirrors_new) { memcpy(conf->mirrors_new, conf->mirrors, sizeof(struct raid10_info)*conf->prev.raid_disks); smp_mb(); @@ -4415,20 +4442,24 @@ static int raid10_start_reshape(struct mddev *mddev) smp_mb(); if (mddev->reshape_backwards) { sector_t size =3D raid10_size(mddev, 0, 0); if (size < mddev->array_sectors) { spin_unlock_irq(&conf->device_lock); + mddev_unlock_and_resume(mddev); + mddev_lock_nointr(mddev); pr_warn("md/raid10:%s: array size must be reduce before number of disks= \n", mdname(mddev)); return -EINVAL; } mddev->resync_max_sectors =3D size; conf->reshape_progress =3D size; } else conf->reshape_progress =3D 0; conf->reshape_safe =3D conf->reshape_progress; spin_unlock_irq(&conf->device_lock); + mddev_unlock_and_resume(mddev); + mddev_lock_nointr(mddev); =20 if (mddev->delta_disks && mddev->bitmap) { struct mdp_superblock_1 *sb =3D NULL; sector_t oldsize, newsize; =20 diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h index ec79d87fb92f..b711626a5db7 100644 --- a/drivers/md/raid10.h +++ b/drivers/md/raid10.h @@ -85,11 +85,11 @@ struct r10conf { int have_replacement; /* There is at least one * replacement device. */ wait_queue_head_t wait_barrier; =20 - mempool_t r10bio_pool; + mempool_t *r10bio_pool; mempool_t r10buf_pool; struct page *tmppage; struct bio_set bio_split; =20 /* When taking over an array from a different personality, we store --=20 2.54.0 From nobody Tue Jun 9 00:49:57 2026 Received: from va-2-26.ptr.blmpb.com (va-2-26.ptr.blmpb.com [209.127.231.26]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A610E276038 for ; Mon, 25 May 2026 01:55:49 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.127.231.26 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779674151; cv=none; b=umr0mjrkPuUaSp9eanYcwU2xBQSdHaSWvL7rD+/N6bXnNDZhP3XyLBRN07HhLRAC1wY0nhmFw5kDXMCy8PwTrLCBIxODeyjZ5qn6G82DH8L6ysigaT7P7/7DGJGRGXkhr4XH8EBl4V+Du8Cn5abPCyuWPggkKXlAAIQC1BUNhR0= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1779674151; c=relaxed/simple; bh=eqOCP2Flce3RuZNEaRmrvZcZSnLJcbIq2CTmYiTpwMg=; h=From:Subject:Date:Mime-Version:To:Cc:Content-Type:Message-Id: In-Reply-To:References; b=sxjnz4ZzRM2QFwaJvHpIQAvfPO/PdQP+4k+2J+WX4QTOUUIl5H/VGTN0hHgC2sYL/Kj/uLEilbD9p3PXkJLPoGSO/YdqeRS/4K3wNV8EjSQHggnrRU3K8JJSBXEPhukpB1xk3Kvu9UkA40spQc+jGWRFxVpRnn/apuLFFMDnDZ4= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=fnnas.com; spf=pass smtp.mailfrom=fnnas.com; dkim=pass (2048-bit key) header.d=fnnas-com.20200927.dkim.feishu.cn header.i=@fnnas-com.20200927.dkim.feishu.cn header.b=Hf4OE270; arc=none smtp.client-ip=209.127.231.26 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=fnnas.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=fnnas.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=fnnas-com.20200927.dkim.feishu.cn header.i=@fnnas-com.20200927.dkim.feishu.cn header.b="Hf4OE270" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; s=s1; d=fnnas-com.20200927.dkim.feishu.cn; t=1779674139; h=from:subject:mime-version:from:date:message-id:subject:to:cc: reply-to:content-type:mime-version:in-reply-to:message-id; bh=PxXAHw+BWXBTzkTHIP97NpyVqmc8V+5qTaihnCkJed8=; b=Hf4OE270gkI1QpbJjzPqkGdeiyYLMXZMFE2oqolSEYtQDJYymnmoiPz/lnQDjoRsJx9+nM CPaviIQACfbKWuRoS+mSLA0/tV3BPZnfnUHbHSrhbAlEwTBV1s5bWbdi70TZyuzZxmpJKw FSaqSTucGMnBWgY7BokNdY7WAca0Wg6hKnKlCEBJl97Sc//a1LeAR0dRiX/zk3J82R8gja RBdUJ5kGew+jeBIUbi6v2l9MGpSBECOgNprKqJzid9XhXoVSIjLhAmQFfIwZv8kIMhQ6Ej Tn4bv0rdHVDgap4yF8B7BmR/GkwEkINZaSjOyfO71gjin25kSU7bA7RXKgA72A== From: "Chen Cheng" Subject: [PATCH v3 2/2] md/raid10: bound reused r10bio devs[] walks by used_nr_devs Date: Mon, 25 May 2026 09:55:20 +0800 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 X-Original-From: chencheng@fnnas.com Received: from localhost.localdomain ([113.111.141.72]) by smtp.feishu.cn with ESMTPS; Mon, 25 May 2026 09:55:37 +0800 To: "Yu Kuai" , Cc: "Chen Cheng" , X-Mailer: git-send-email 2.54.0 Message-Id: <20260525015520.2565423-3-chencheng@fnnas.com> In-Reply-To: <20260525015520.2565423-1-chencheng@fnnas.com> X-Lms-Return-Path: References: <20260525015520.2565423-1-chencheng@fnnas.com> Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" From: Chen Cheng After reshape changes raid_disks, an in-flight r10bio from the old geometry can still be completed or freed later. In that case, using the current geometry to walk r10_bio->devs[] is unsafe. A failure was reproduced with a simple write workload while reshaping a raid10 array from 4 disks to 5 disk= s. e.g.: mdadm -C /dev/md777 -l10 -n4 /dev/sda /dev/sdb /dev/sdc /dev/sdd mkfs.ext4 /dev/md777 mount /dev/md777 /mnt/test fsstress -d /mnt/test -n 24000 -p 8 -l 24 & mdadm /dev/md777 --add /dev/sde mdadm --grow /dev/md777 --raid-devices=3D5 \ --backup-file=3D/tmp/md-reshape-backup the sequence above can trigger: BUG: KASAN: slab-out-of-bounds in free_r10bio+0x1c4/0x260 [raid10] Read of size 8 at addr ffff00008c2dfac8 by task ksoftirqd/0/15 free_r10bio raid_end_bio_io one_write_done raid10_end_write_request The buggy object was 200 bytes long, which matches an r10bio with space for only four devs[] entries. However, put_all_bios() and find_bio_disk() walk r10_bio->devs[] using the current conf->geo.raid_disks value. Once reshape switches conf->geo.raid_disks from 4 to 5, an old 4-slot r10bio can be completed or freed as if it had 5 slots, and the walk overruns devs[4]. The same stale-width mismatch can also surface during a 5-disk to 4-disk reshap= e. Track the number of valid devs[] entries in each reused r10bio with used_nr_devs. Initialize it whenever an r10bio is prepared for regular I/O, discard, or resync/recovery/reshape work, and use it to bound devs[] walks in put_all_bios() and find_bio_disk(). Signed-off-by: Chen Cheng --- drivers/md/raid10.c | 8 ++++++-- drivers/md/raid10.h | 2 ++ 2 files changed, 8 insertions(+), 2 deletions(-) diff --git a/drivers/md/raid10.c b/drivers/md/raid10.c index 64677dbe5152..d4695fa9c076 100644 --- a/drivers/md/raid10.c +++ b/drivers/md/raid10.c @@ -273,11 +273,11 @@ static void r10buf_pool_free(void *__r10_bio, void *d= ata) =20 static void put_all_bios(struct r10conf *conf, struct r10bio *r10_bio) { int i; =20 - for (i =3D 0; i < conf->geo.raid_disks; i++) { + for (i =3D 0; i < r10_bio->used_nr_devs; i++) { struct bio **bio =3D & r10_bio->devs[i].bio; if (!BIO_SPECIAL(*bio)) bio_put(*bio); *bio =3D NULL; bio =3D &r10_bio->devs[i].repl_bio; @@ -370,11 +370,11 @@ static int find_bio_disk(struct r10conf *conf, struct= r10bio *r10_bio, struct bio *bio, int *slotp, int *replp) { int slot; int repl =3D 0; =20 - for (slot =3D 0; slot < conf->geo.raid_disks; slot++) { + for (slot =3D 0; slot < r10_bio->used_nr_devs; slot++) { if (r10_bio->devs[slot].bio =3D=3D bio) break; if (r10_bio->devs[slot].repl_bio =3D=3D bio) { repl =3D 1; break; @@ -1553,10 +1553,11 @@ static void __make_request(struct mddev *mddev, str= uct bio *bio, int sectors) =20 r10_bio->mddev =3D mddev; r10_bio->sector =3D bio->bi_iter.bi_sector; r10_bio->state =3D 0; r10_bio->read_slot =3D -1; + r10_bio->used_nr_devs =3D conf->geo.raid_disks; memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * conf->geo.raid_disks); =20 if (bio_data_dir(bio) =3D=3D READ) raid10_read_request(mddev, bio, r10_bio, true); @@ -1740,10 +1741,11 @@ static int raid10_handle_discard(struct mddev *mdde= v, struct bio *bio) retry_discard: r10_bio =3D mempool_alloc(conf->r10bio_pool, GFP_NOIO); r10_bio->mddev =3D mddev; r10_bio->state =3D 0; r10_bio->sectors =3D 0; + r10_bio->used_nr_devs =3D geo->raid_disks; memset(r10_bio->devs, 0, sizeof(r10_bio->devs[0]) * geo->raid_disks); wait_blocked_dev(mddev, r10_bio); =20 /* * For far layout it needs more than one r10bio to cover all regions. @@ -3074,10 +3076,12 @@ static struct r10bio *raid10_alloc_init_r10buf(stru= ct r10conf *conf) test_bit(MD_RECOVERY_RESHAPE, &conf->mddev->recovery)) nalloc =3D conf->copies; /* resync */ else nalloc =3D 2; /* recovery */ =20 + r10bio->used_nr_devs =3D nalloc; + for (i =3D 0; i < nalloc; i++) { bio =3D r10bio->devs[i].bio; rp =3D bio->bi_private; bio_reset(bio, NULL, 0); bio->bi_private =3D rp; diff --git a/drivers/md/raid10.h b/drivers/md/raid10.h index b711626a5db7..4751119f9770 100644 --- a/drivers/md/raid10.h +++ b/drivers/md/raid10.h @@ -125,10 +125,12 @@ struct r10bio { struct bio *master_bio; /* * if the IO is in READ direction, then this is where we read */ int read_slot; + /* Used to bound devs[] walks when the object is reused. */ + unsigned int used_nr_devs; =20 struct list_head retry_list; /* * if the IO is in WRITE direction, then multiple bios are used, * one for each copy. --=20 2.54.0