From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793209660; b=dkOVLVTfz9+34Mx8Iy+2Bdm/vUQ8ie3BELiHngiP+TsHZ8Dext/HCOGvThfzPTe5wZSa +5bgXRyVv6AshoJqTx/rW0hs/y6TxcKH7RrOcMzovV0Z/i6fD4H2n2JfQ4JyUDwUiWvjJ zZllRpHAjbTkIGlbQi44kBagl+/yrQiWsLbhbCm36CoBEV+04njHmA8NJF3zwYKVsLrty riWaT0vyKKm0FSEZGBNwDo52YT3AUe9YFAlRbKj1eTambqxALXAAnQF9/bTb4oBF0bHg2 YWcrQGD7MNUEHAsx2jtU940CAch4Jy2GRJbIdwsBm50s9aO8FR2fG4f+Ue8qYR5jkJg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793209660; h=Received:DKIM-Signature:From:To:Cc:Subject:Date:Message-ID:X-Mailer: In-Reply-To:References:User-Agent:X-stable:X-Patchwork-Hint: MIME-Version:Content-Transfer-Encoding; bh=NfzExC0j3mzSZLHjFTXsle5X19B7lIlkRfUZ+/GUnAU=; b=MPJnTjkQbqerWeqtrhpde56ZAAWd/JUVeoIM2IGDCh+HizRezob73zouogQpd3N8M9Lx 5ETubkb6Dj4RjE154z5WRNyK8kwtcRHl3gV69IgIveuS6MS+VOKNVPyE8JZ0y6ingElfG TBOyt8i353wYqDmAcZzByOQsLRMBQLDlXMVv7YX1c1uZTehEuddoG+UmkJegbOYZE2frp bj9Z8CeXohvbMIU6ILbDdsLMxsvdzRHyXdcD/iBNCoVfy1ohELO3vY+isiqoM+35DxQBf RCVKYhB1l2QobEnQO4/cvcMFFOZnEPsQvi3o86j2LSRPn3cQBOCyqxq/7LimaYi10zA== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=ISZV2lvc; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id EC12F606A31A; Wed, 28 Oct 2026 17:47:39 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key, unprotected) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.a=rsa-sha256 header.s=korg header.b=ISZV2lvc Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4D8391F01825; Wed, 28 Oct 2026 17:47:39 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1793209659; bh=NfzExC0j3mzSZLHjFTXsle5X19B7lIlkRfUZ+/GUnAU=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=ISZV2lvcOhsI85jb5+AFi5DOB590gdGa+RjN0UljCA6s2OiwJDCFAugGJpbik3t5C 344KglVlqLM0zs87wU+CwHVxWeLkL2CeD00nRm6BfH8d/u/WXp9xkew6kZtO9ufH2w xtr+1lzamcHc4z2kHwc8gbIQJmkhKoggkR82BvoQ= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, stable@vger.kernek.org, Damien Le Moal , Christoph Hellwig , Hannes Reinecke , Jens Axboe , Stanley Jhu , Sasha Levin Subject: [PATCH 6.18 031/109] block: avoid potential deadlock on zone revalidation failure Date: Wed, 28 Oct 2026 18:00:15 +0100 Message-ID: <20261028165943.095378496@linuxfoundation.org> X-Mailer: git-send-email 2.56.0 In-Reply-To: <20261028165942.357251485@linuxfoundation.org> References: <20261028165942.357251485@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore X-Mailing-List: patches@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Damien Le Moal commit 3dd63dba8f9cb6990a40af7ed66ee0159f475819 upstream. If revalidating the zones of a zoned block device with blk_revalidate_disk_zones() fails during a SCSI disk rescan, the following lockdep splat is thrown: [ 347.251859] [ T11230] sda: failed to revalidate zones [ 347.261380] [ T11230] ====================================================== [ 347.263882] [ T11230] WARNING: possible circular locking dependency detected [ 347.266353] [ T11230] 7.1.0+ #1194 Not tainted [ 347.268052] [ T11230] ------------------------------------------------------ [ 347.270537] [ T11230] tcsh/11230 is trying to acquire lock: [ 347.272555] [ T11230] ffffffff8f91d400 (wq_pool_mutex){+.+.}-{4:4}, at: destroy_workqueue+0x15d/0x8d0 [ 347.275914] [ T11230] but task is already holding lock: [ 347.278646] [ T11230] ffff88812fa1bcc0 (&q->q_usage_counter(io)#5){++++}-{0:0}, at: blk_mq_freeze_queue_nomemsave+0x16/0x30 [ 347.282503] [ T11230] which lock already depends on the new lock. [ 347.286239] [ T11230] the existing dependency chain (in reverse order) is: [ 347.289408] [ T11230] -> #2 (&q->q_usage_counter(io)#5){++++}-{0:0}: [ 347.292437] [ T11230] blk_alloc_queue+0x5ca/0x750 [ 347.294379] [ T11230] blk_mq_alloc_queue+0x14c/0x240 [ 347.296375] [ T11230] scsi_alloc_sdev+0x871/0xd10 [scsi_mod] [ 347.298619] [ T11230] scsi_probe_and_add_lun+0x600/0xc50 [scsi_mod] [ 347.301056] [ T11230] __scsi_scan_target+0x187/0x3b0 [scsi_mod] [ 347.303385] [ T11230] scsi_scan_channel+0xf2/0x180 [scsi_mod] [ 347.305651] [ T11230] scsi_scan_host_selected+0x20b/0x2d0 [scsi_mod] [ 347.308119] [ T11230] do_scan_async+0x42/0x420 [scsi_mod] [ 347.310276] [ T11230] async_run_entry_fn+0x94/0x5a0 [ 347.312284] [ T11230] process_one_work+0x8da/0x1690 [ 347.314287] [ T11230] worker_thread+0x5fe/0x1010 [ 347.316216] [ T11230] kthread+0x358/0x450 [ 347.317675] [ T11230] ret_from_fork+0x5b9/0x8e0 [ 347.319181] [ T11230] ret_from_fork_asm+0x11/0x20 [ 347.320778] [ T11230] -> #1 (fs_reclaim){+.+.}-{0:0}: [ 347.322890] [ T11230] fs_reclaim_acquire+0xd5/0x120 [ 347.324464] [ T11230] __kmalloc_cache_node_noprof+0x39/0x620 [ 347.326223] [ T11230] init_rescuer+0x19b/0x560 [ 347.327697] [ T11230] workqueue_init+0x33b/0x6a0 [ 347.329224] [ T11230] kernel_init_freeable+0x2eb/0x600 [ 347.330881] [ T11230] kernel_init+0x1c/0x140 [ 347.332334] [ T11230] ret_from_fork+0x5b9/0x8e0 [ 347.333847] [ T11230] ret_from_fork_asm+0x11/0x20 [ 347.335360] [ T11230] -> #0 (wq_pool_mutex){+.+.}-{4:4}: [ 347.337510] [ T11230] __lock_acquire+0xdea/0x2260 [ 347.339030] [ T11230] lock_acquire+0x187/0x2f0 [ 347.340495] [ T11230] __mutex_lock+0x1ab/0x2600 [ 347.341464] [ T11230] destroy_workqueue+0x15d/0x8d0 [ 347.342485] [ T11230] disk_free_zone_resources+0xd5/0x560 [ 347.343577] [ T11230] blk_revalidate_disk_zones+0x620/0xac7 [ 347.344723] [ T11230] sd_zbc_revalidate_zones+0x1dd/0x790 [sd_mod] [ 347.345938] [ T11230] sd_revalidate_disk+0xc66/0x8e60 [sd_mod] [ 347.347112] [ T11230] scsi_rescan_device+0x1f9/0x310 [scsi_mod] [ 347.348318] [ T11230] store_rescan_field+0x19/0x20 [scsi_mod] [ 347.349507] [ T11230] kernfs_fop_write_iter+0x3d2/0x5e0 [ 347.350565] [ T11230] vfs_write+0x469/0x1000 [ 347.351484] [ T11230] ksys_write+0x116/0x250 [ 347.352403] [ T11230] do_syscall_64+0xf0/0x6e0 [ 347.353361] [ T11230] entry_SYSCALL_64_after_hwframe+0x4b/0x53 [ 347.354533] [ T11230] other info that might help us debug this: [ 347.356432] [ T11230] Chain exists of: wq_pool_mutex --> fs_reclaim --> &q->q_usage_counter(io)#5 [ 347.358919] [ T11230] Possible unsafe locking scenario: [ 347.360307] [ T11230] CPU0 CPU1 [ 347.361327] [ T11230] ---- ---- [ 347.362340] [ T11230] lock(&q->q_usage_counter(io)#5); [ 347.363344] [ T11230] lock(fs_reclaim); [ 347.364526] [ T11230] lock(&q->q_usage_counter(io)#5); [ 347.365968] [ T11230] lock(wq_pool_mutex); [ 347.366811] [ T11230] *** DEADLOCK *** This happens because SCSI disk rescan is executed from a work context and a failure of blk_revalidate_disk_zones() causes a call to disk_free_zone_resources() which will free the disk zone write plug workqueue. Avoid this by delaying the destruction of the disk zone write plug workqueue to disk_release(). Do this by introducing the function disk_release_zone_resources() and using this new function from disk_release(). This new function destroys the zone write plugs workqueue and calls disk_free_zone_resources(), thus allowing to remove the call to destroy_workqueue() from disk_free_zone_resources(). disk_alloc_zone_resources() is modified to not create the disk zone write plug work queue if it already exists. Fixes: a8f59e5a5dea ("block: use a per disk workqueue for zone write plugging") Cc: stable@vger.kernek.org Signed-off-by: Damien Le Moal Reviewed-by: Christoph Hellwig Reviewed-by: Hannes Reinecke Link: https://patch.msgid.link/20260701082155.1369996-1-dlemoal@kernel.org Signed-off-by: Jens Axboe [ stanleyjhu: 6.18.y has no zone write plug kthread worker and does not use WQ_PERCPU, so only the workqueue part applies: disk_alloc_zone_resources() reuses an existing workqueue, disk_free_zone_resources() drains it instead of destroying it, and the new disk_release_zone_resources() destroys it from disk_release(). ] Signed-off-by: Stanley Jhu Signed-off-by: Sasha Levin --- block/blk-zoned.c | 37 +++++++++++++++++++++++++++---------- block/blk.h | 4 ++-- block/genhd.c | 2 +- 3 files changed, 30 insertions(+), 13 deletions(-) diff --git a/block/blk-zoned.c b/block/blk-zoned.c index 5c16cf96b97c1..a7d3d2e002da6 100644 --- a/block/blk-zoned.c +++ b/block/blk-zoned.c @@ -1413,11 +1413,20 @@ static int disk_alloc_zone_resources(struct gendisk *disk, if (!disk->zone_wplugs_pool) goto free_hash; - disk->zone_wplugs_wq = - alloc_workqueue("%s_zwplugs", WQ_MEM_RECLAIM | WQ_HIGHPRI, - pool_size, disk->disk_name); - if (!disk->zone_wplugs_wq) - goto destroy_pool; + /* + * We may already have a zone write plug workqueue as this function may + * be called after disk_free_zone_resources(), which does not destroy + * the workqueue (the zone write plugs workqueue is destroyed at + * disk_release() time). + */ + if (!disk->zone_wplugs_wq) { + disk->zone_wplugs_wq = + alloc_workqueue("%s_zwplugs", + WQ_MEM_RECLAIM | WQ_HIGHPRI, + pool_size, disk->disk_name); + if (!disk->zone_wplugs_wq) + goto destroy_pool; + } return 0; @@ -1474,15 +1483,13 @@ static unsigned int disk_set_conv_zones_bitmap(struct gendisk *disk, return nr_conv_zones; } -void disk_free_zone_resources(struct gendisk *disk) +static void disk_free_zone_resources(struct gendisk *disk) { if (!disk->zone_wplugs_pool) return; - if (disk->zone_wplugs_wq) { - destroy_workqueue(disk->zone_wplugs_wq); - disk->zone_wplugs_wq = NULL; - } + if (disk->zone_wplugs_wq) + drain_workqueue(disk->zone_wplugs_wq); disk_destroy_zone_wplugs_hash_table(disk); @@ -1501,6 +1508,16 @@ void disk_free_zone_resources(struct gendisk *disk) disk->nr_zones = 0; } +void disk_release_zone_resources(struct gendisk *disk) +{ + if (disk->zone_wplugs_wq) { + destroy_workqueue(disk->zone_wplugs_wq); + disk->zone_wplugs_wq = NULL; + } + + disk_free_zone_resources(disk); +} + static inline bool disk_need_zone_resources(struct gendisk *disk) { /* diff --git a/block/blk.h b/block/blk.h index 2810b4d086e6a..179662b868998 100644 --- a/block/blk.h +++ b/block/blk.h @@ -499,7 +499,7 @@ static inline void ioc_clear_queue(struct request_queue *q) #ifdef CONFIG_BLK_DEV_ZONED void disk_init_zone_resources(struct gendisk *disk); -void disk_free_zone_resources(struct gendisk *disk); +void disk_release_zone_resources(struct gendisk *disk); static inline bool bio_zone_write_plugging(struct bio *bio) { return bio_flagged(bio, BIO_ZONE_WRITE_PLUGGING); @@ -552,7 +552,7 @@ int blkdev_zone_mgmt_ioctl(struct block_device *bdev, blk_mode_t mode, static inline void disk_init_zone_resources(struct gendisk *disk) { } -static inline void disk_free_zone_resources(struct gendisk *disk) +static inline void disk_release_zone_resources(struct gendisk *disk) { } static inline bool bio_zone_write_plugging(struct bio *bio) diff --git a/block/genhd.c b/block/genhd.c index bbcfbd1a363c5..6ba0e22ce9dff 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -1308,7 +1308,7 @@ static void disk_release(struct device *dev) disk_release_events(disk); kfree(disk->random); - disk_free_zone_resources(disk); + disk_release_zone_resources(disk); xa_destroy(&disk->part_tbl); kobject_put(&disk->queue_kobj); -- 2.53.0