kernel/linux.git/block/genhd.c, branch v6.12.80

block: rate-limit capacity change info log

2026-01-08T09:14:14+00:00

commit 3179a5f7f86bcc3acd5d6fb2a29f891ef5615852 upstream. loop devices under heavy stress-ng loop streessor can trigger many capacity change events in a short time. Each event prints an info message from set_capacity_and_notify(), flooding the console and contributing to soft lockups on slow consoles. Switch the printk in set_capacity_and_notify() to pr_info_ratelimited() so frequent capacity changes do not spam the log while still reporting occasional changes. Cc: stable@vger.kernel.org Signed-off-by: Li Chen Reviewed-by: Chaitanya Kulkarni Reviewed-by: Bart Van Assche Signed-off-by: Jens Axboe Signed-off-by: Greg Kroah-Hartman

block: retry call probe after request_module in blk_request_module

2025-02-08T08:56:51+00:00

[ Upstream commit 457ef47c08d2979f3e59ce66267485c3faed70c8 ] Set kernel config: CONFIG_BLK_DEV_LOOP=m CONFIG_BLK_DEV_LOOP_MIN_COUNT=0 Do latter: mknod loop0 b 7 0 exec 4<> loop0 Before commit e418de3abcda ("block: switch gendisk lookup to a simple xarray"), lookup_gendisk will first use base_probe to load module loop, and then the retry will call loop_probe to prepare the loop disk. Finally open for this disk will success. However, after this commit, we lose the retry logic, and open will fail with ENXIO. Block device autoloading is deprecated and will be removed soon, but maybe we should keep open success until we really remove it. So, give a retry to fix it. Fixes: e418de3abcda ("block: switch gendisk lookup to a simple xarray") Suggested-by: Christoph Hellwig Signed-off-by: Yang Erkun Reviewed-by: Christoph Hellwig Link: https://lore.kernel.org/r/20241209110435.3670985-1-yangerkun@huaweicloud.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

block: fix uaf for flush rq while iterating tags

2024-12-05T13:03:06+00:00

[ Upstream commit 3802f73bd80766d70f319658f334754164075bc3 ] blk_mq_clear_flush_rq_mapping() is not called during scsi probe, by checking blk_queue_init_done(). However, QUEUE_FLAG_INIT_DONE is cleared in del_gendisk by commit aec89dc5d421 ("block: keep q_usage_counter in atomic mode after del_gendisk"), hence for disk like scsi, following blk_mq_destroy_queue() will not clear flush rq from tags->rqs[] as well, cause following uaf that is found by our syzkaller for v6.6: ================================================================== BUG: KASAN: slab-use-after-free in blk_mq_find_and_get_req+0x16e/0x1a0 block/blk-mq-tag.c:261 Read of size 4 at addr ffff88811c969c20 by task kworker/1:2H/224909 CPU: 1 PID: 224909 Comm: kworker/1:2H Not tainted 6.6.0-ga836a5060850 #32 Workqueue: kblockd blk_mq_timeout_work Call Trace: __dump_stack lib/dump_stack.c:88 [inline] dump_stack_lvl+0x91/0xf0 lib/dump_stack.c:106 print_address_description.constprop.0+0x66/0x300 mm/kasan/report.c:364 print_report+0x3e/0x70 mm/kasan/report.c:475 kasan_report+0xb8/0xf0 mm/kasan/report.c:588 blk_mq_find_and_get_req+0x16e/0x1a0 block/blk-mq-tag.c:261 bt_iter block/blk-mq-tag.c:288 [inline] __sbitmap_for_each_set include/linux/sbitmap.h:295 [inline] sbitmap_for_each_set include/linux/sbitmap.h:316 [inline] bt_for_each+0x455/0x790 block/blk-mq-tag.c:325 blk_mq_queue_tag_busy_iter+0x320/0x740 block/blk-mq-tag.c:534 blk_mq_timeout_work+0x1a3/0x7b0 block/blk-mq.c:1673 process_one_work+0x7c4/0x1450 kernel/workqueue.c:2631 process_scheduled_works kernel/workqueue.c:2704 [inline] worker_thread+0x804/0xe40 kernel/workqueue.c:2785 kthread+0x346/0x450 kernel/kthread.c:388 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:293 Allocated by task 942: kasan_save_stack+0x22/0x50 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 ____kasan_kmalloc mm/kasan/common.c:374 [inline] __kasan_kmalloc mm/kasan/common.c:383 [inline] __kasan_kmalloc+0xaa/0xb0 mm/kasan/common.c:380 kasan_kmalloc include/linux/kasan.h:198 [inline] __do_kmalloc_node mm/slab_common.c:1007 [inline] __kmalloc_node+0x69/0x170 mm/slab_common.c:1014 kmalloc_node include/linux/slab.h:620 [inline] kzalloc_node include/linux/slab.h:732 [inline] blk_alloc_flush_queue+0x144/0x2f0 block/blk-flush.c:499 blk_mq_alloc_hctx+0x601/0x940 block/blk-mq.c:3788 blk_mq_alloc_and_init_hctx+0x27f/0x330 block/blk-mq.c:4261 blk_mq_realloc_hw_ctxs+0x488/0x5e0 block/blk-mq.c:4294 blk_mq_init_allocated_queue+0x188/0x860 block/blk-mq.c:4350 blk_mq_init_queue_data block/blk-mq.c:4166 [inline] blk_mq_init_queue+0x8d/0x100 block/blk-mq.c:4176 scsi_alloc_sdev+0x843/0xd50 drivers/scsi/scsi_scan.c:335 scsi_probe_and_add_lun+0x77c/0xde0 drivers/scsi/scsi_scan.c:1189 __scsi_scan_target+0x1fc/0x5a0 drivers/scsi/scsi_scan.c:1727 scsi_scan_channel drivers/scsi/scsi_scan.c:1815 [inline] scsi_scan_channel+0x14b/0x1e0 drivers/scsi/scsi_scan.c:1791 scsi_scan_host_selected+0x2fe/0x400 drivers/scsi/scsi_scan.c:1844 scsi_scan+0x3a0/0x3f0 drivers/scsi/scsi_sysfs.c:151 store_scan+0x2a/0x60 drivers/scsi/scsi_sysfs.c:191 dev_attr_store+0x5c/0x90 drivers/base/core.c:2388 sysfs_kf_write+0x11c/0x170 fs/sysfs/file.c:136 kernfs_fop_write_iter+0x3fc/0x610 fs/kernfs/file.c:338 call_write_iter include/linux/fs.h:2083 [inline] new_sync_write+0x1b4/0x2d0 fs/read_write.c:493 vfs_write+0x76c/0xb00 fs/read_write.c:586 ksys_write+0x127/0x250 fs/read_write.c:639 do_syscall_x64 arch/x86/entry/common.c:51 [inline] do_syscall_64+0x70/0x120 arch/x86/entry/common.c:81 entry_SYSCALL_64_after_hwframe+0x78/0xe2 Freed by task 244687: kasan_save_stack+0x22/0x50 mm/kasan/common.c:45 kasan_set_track+0x25/0x30 mm/kasan/common.c:52 kasan_save_free_info+0x2b/0x50 mm/kasan/generic.c:522 ____kasan_slab_free mm/kasan/common.c:236 [inline] __kasan_slab_free+0x12a/0x1b0 mm/kasan/common.c:244 kasan_slab_free include/linux/kasan.h:164 [inline] slab_free_hook mm/slub.c:1815 [inline] slab_free_freelist_hook mm/slub.c:1841 [inline] slab_free mm/slub.c:3807 [inline] __kmem_cache_free+0xe4/0x520 mm/slub.c:3820 blk_free_flush_queue+0x40/0x60 block/blk-flush.c:520 blk_mq_hw_sysfs_release+0x4a/0x170 block/blk-mq-sysfs.c:37 kobject_cleanup+0x136/0x410 lib/kobject.c:689 kobject_release lib/kobject.c:720 [inline] kref_put include/linux/kref.h:65 [inline] kobject_put+0x119/0x140 lib/kobject.c:737 blk_mq_release+0x24f/0x3f0 block/blk-mq.c:4144 blk_free_queue block/blk-core.c:298 [inline] blk_put_queue+0xe2/0x180 block/blk-core.c:314 blkg_free_workfn+0x376/0x6e0 block/blk-cgroup.c:144 process_one_work+0x7c4/0x1450 kernel/workqueue.c:2631 process_scheduled_works kernel/workqueue.c:2704 [inline] worker_thread+0x804/0xe40 kernel/workqueue.c:2785 kthread+0x346/0x450 kernel/kthread.c:388 ret_from_fork+0x4d/0x80 arch/x86/kernel/process.c:147 ret_from_fork_asm+0x1b/0x30 arch/x86/entry/entry_64.S:293 Other than blk_mq_clear_flush_rq_mapping(), the flag is only used in blk_register_queue() from initialization path, hence it's safe not to clear the flag in del_gendisk. And since QUEUE_FLAG_REGISTERED already make sure that queue should only be registered once, there is no need to test the flag as well. Fixes: 6cfeadbff3f8 ("blk-mq: don't clear flush_rq from tags->rqs[]") Depends-on: commit aec89dc5d421 ("block: keep q_usage_counter in atomic mode after del_gendisk") Signed-off-by: Yu Kuai Reviewed-by: Ming Lei Link: https://lore.kernel.org/r/20241104110005.1412161-1-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe Signed-off-by: Sasha Levin

block: model freeze & enter queue as lock for supporting lockdep

2024-12-05T13:03:05+00:00

[ Upstream commit f1be1788a32e8fa63416ad4518bbd1a85a825c9d ] Recently we got several deadlock report[1][2][3] caused by blk_mq_freeze_queue and blk_enter_queue(). Turns out the two are just like acquiring read/write lock, so model them as read/write lock for supporting lockdep: 1) model q->q_usage_counter as two locks(io and queue lock) - queue lock covers sync with blk_enter_queue() - io lock covers sync with bio_enter_queue() 2) make the lockdep class/key as per-queue: - different subsystem has very different lock use pattern, shared lock class causes false positive easily - freeze_queue degrades to no lock in case that disk state becomes DEAD because bio_enter_queue() won't be blocked any more - freeze_queue degrades to no lock in case that request queue becomes dying because blk_enter_queue() won't be blocked any more 3) model blk_mq_freeze_queue() as acquire_exclusive & try_lock - it is exclusive lock, so dependency with blk_enter_queue() is covered - it is trylock because blk_mq_freeze_queue() are allowed to run concurrently 4) model blk_enter_queue() & bio_enter_queue() as acquire_read() - nested blk_enter_queue() are allowed - dependency with blk_mq_freeze_queue() is covered - blk_queue_exit() is often called from other contexts(such as irq), and it can't be annotated as lock_release(), so simply do it in blk_enter_queue(), this way still covered cases as many as possible With lockdep support, such kind of reports may be reported asap and needn't wait until the real deadlock is triggered. For example, lockdep report can be triggered in the report[3] with this patch applied. [1] occasional block layer hang when setting 'echo noop > /sys/block/sda/queue/scheduler' https://bugzilla.kernel.org/show_bug.cgi?id=219166 [2] del_gendisk() vs blk_queue_enter() race condition https://lore.kernel.org/linux-block/20241003085610.GK11458@google.com/ [3] queue_freeze & queue_enter deadlock in scsi https://lore.kernel.org/linux-block/ZxG38G9BuFdBpBHZ@fedora/T/#u Reviewed-by: Christoph Hellwig Signed-off-by: Ming Lei Link: https://lore.kernel.org/r/20241025003722.3630252-4-ming.lei@redhat.com Signed-off-by: Jens Axboe Stable-dep-of: 3802f73bd807 ("block: fix uaf for flush rq while iterating tags") Signed-off-by: Sasha Levin

block: fix deadlock between sd_remove & sd_release

2024-07-24T15:51:21+00:00

Our test report the following hung task: [ 2538.459400] INFO: task "kworker/0:0":7 blocked for more than 188 seconds. [ 2538.459427] Call trace: [ 2538.459430] __switch_to+0x174/0x338 [ 2538.459436] __schedule+0x628/0x9c4 [ 2538.459442] schedule+0x7c/0xe8 [ 2538.459447] schedule_preempt_disabled+0x24/0x40 [ 2538.459453] __mutex_lock+0x3ec/0xf04 [ 2538.459456] __mutex_lock_slowpath+0x14/0x24 [ 2538.459459] mutex_lock+0x30/0xd8 [ 2538.459462] del_gendisk+0xdc/0x350 [ 2538.459466] sd_remove+0x30/0x60 [ 2538.459470] device_release_driver_internal+0x1c4/0x2c4 [ 2538.459474] device_release_driver+0x18/0x28 [ 2538.459478] bus_remove_device+0x15c/0x174 [ 2538.459483] device_del+0x1d0/0x358 [ 2538.459488] __scsi_remove_device+0xa8/0x198 [ 2538.459493] scsi_forget_host+0x50/0x70 [ 2538.459497] scsi_remove_host+0x80/0x180 [ 2538.459502] usb_stor_disconnect+0x68/0xf4 [ 2538.459506] usb_unbind_interface+0xd4/0x280 [ 2538.459510] device_release_driver_internal+0x1c4/0x2c4 [ 2538.459514] device_release_driver+0x18/0x28 [ 2538.459518] bus_remove_device+0x15c/0x174 [ 2538.459523] device_del+0x1d0/0x358 [ 2538.459528] usb_disable_device+0x84/0x194 [ 2538.459532] usb_disconnect+0xec/0x300 [ 2538.459537] hub_event+0xb80/0x1870 [ 2538.459541] process_scheduled_works+0x248/0x4dc [ 2538.459545] worker_thread+0x244/0x334 [ 2538.459549] kthread+0x114/0x1bc [ 2538.461001] INFO: task "fsck.":15415 blocked for more than 188 seconds. [ 2538.461014] Call trace: [ 2538.461016] __switch_to+0x174/0x338 [ 2538.461021] __schedule+0x628/0x9c4 [ 2538.461025] schedule+0x7c/0xe8 [ 2538.461030] blk_queue_enter+0xc4/0x160 [ 2538.461034] blk_mq_alloc_request+0x120/0x1d4 [ 2538.461037] scsi_execute_cmd+0x7c/0x23c [ 2538.461040] ioctl_internal_command+0x5c/0x164 [ 2538.461046] scsi_set_medium_removal+0x5c/0xb0 [ 2538.461051] sd_release+0x50/0x94 [ 2538.461054] blkdev_put+0x190/0x28c [ 2538.461058] blkdev_release+0x28/0x40 [ 2538.461063] __fput+0xf8/0x2a8 [ 2538.461066] __fput_sync+0x28/0x5c [ 2538.461070] __arm64_sys_close+0x84/0xe8 [ 2538.461073] invoke_syscall+0x58/0x114 [ 2538.461078] el0_svc_common+0xac/0xe0 [ 2538.461082] do_el0_svc+0x1c/0x28 [ 2538.461087] el0_svc+0x38/0x68 [ 2538.461090] el0t_64_sync_handler+0x68/0xbc [ 2538.461093] el0t_64_sync+0x1a8/0x1ac T1: T2: sd_remove del_gendisk __blk_mark_disk_dead blk_freeze_queue_start ++q->mq_freeze_depth bdev_release mutex_lock(&disk->open_mutex) sd_release scsi_execute_cmd blk_queue_enter wait_event(!q->mq_freeze_depth) mutex_lock(&disk->open_mutex) SCSI does not set GD_OWNS_QUEUE, so QUEUE_FLAG_DYING is not set in this scenario. This is a classic ABBA deadlock. To fix the deadlock, make sure we don't try to acquire disk->open_mutex after freezing the queue. Cc: stable@vger.kernel.org Fixes: eec1be4c30df ("block: delete partitions later in del_gendisk") Signed-off-by: Yang Yang Reviewed-by: Ming Lei Reviewed-by: Bart Van Assche Reviewed-by: Christoph Hellwig Fixes: and Cc: stable tags are missing. Otherwise this patch looks fine Link: https://lore.kernel.org/r/20240724070412.22521-1-yang.yang@vivo.com Signed-off-by: Jens Axboe

block: remove disk_update_readahead

2024-06-26T15:37:35+00:00

Mark blk_apply_bdi_limits non-static and open code disk_update_readahead in the only caller. Signed-off-by: Christoph Hellwig Reviewed-by: Damien Le Moal Link: https://lore.kernel.org/r/20240626142637.300624-7-hch@lst.de Signed-off-by: Jens Axboe

Merge tag 'pull-bd_flags-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2024-05-21T20:02:56+00:00

Pull bdev flags update from Al Viro: "Compactifying bdev flags. We can easily have up to 24 flags with sane atomicity, _without_ pushing anything out of the first cacheline of struct block_device" * tag 'pull-bd_flags-2' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: bdev: move ->bd_make_it_fail to ->__bd_flags bdev: move ->bd_ro_warned to ->__bd_flags bdev: move ->bd_has_subit_bio to ->__bd_flags bdev: move ->bd_write_holder into ->__bd_flags bdev: move ->bd_read_only to ->__bd_flags bdev: infrastructure for flags wrapper for access to ->bd_partno Use bdev_is_paritition() instead of open-coding it

Merge tag 'pull-bd_inode-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2024-05-21T16:51:42+00:00

Pull bdev bd_inode updates from Al Viro: "Replacement of bdev->bd_inode with sane(r) set of primitives by me and Yu Kuai" * tag 'pull-bd_inode-1' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: RIP ->bd_inode dasd_format(): killing the last remaining user of ->bd_inode nilfs_attach_log_writer(): use ->bd_mapping->host instead of ->bd_inode block/bdev.c: use the knowledge of inode/bdev coallocation gfs2: more obvious initializations of mapping->host fs/buffer.c: massage the remaining users of ->bd_inode to ->bd_mapping blk_ioctl_{discard,zeroout}(): we only want ->bd_inode->i_mapping here... grow_dev_folio(): we only want ->bd_inode->i_mapping there use ->bd_mapping instead of ->bd_inode->i_mapping block_device: add a pointer to struct address_space (page cache of bdev) missing helpers: bdev_unhash(), bdev_drop() block: move two helpers into bdev.c block2mtd: prevent direct access of bd_inode dm-vdo: use bdev_nr_bytes(bdev) instead of i_size_read(bdev->bd_inode) blkdev_write_iter(): saner way to get inode and bdev bcachefs: remove dead function bdev_sectors() ext4: remove block_device_ejected() erofs_buf: store address_space instead of inode erofs: switch erofs_bread() to passing offset instead of block number

block: fix that util can be greater than 100%

2024-05-09T13:59:44+00:00

util means the percentage that disk has IO, and theoretically it should not be greater than 100%. However, there is a gap for rq-based disk: io_ticks will be updated when rq is allocated, however, before such rq dispatch to driver, it will not be account as inflight from blk_mq_start_request() hence diskstats_show()/part_stat_show() will not update io_ticks. For example: 1) at t0, issue a new IO, rq is allocated, and blk_account_io_start() update io_ticks; 2) something is wrong with drivers, and the rq can't be dispatched; 3) at t0 + 10s, drivers recovers and rq is dispatched and done, io_ticks is updated; Then if user is using "iostat 1" to monitor "util", between t0 - t0+9s, util will be zero, and between t0+9s - t0+10s, util will be 1000%. Fix this problem by updating io_ticks from diskstats_show() and part_stat_show() if there are rq allocated. Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20240509123717.3223892-3-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe

block: support to account io_ticks precisely

2024-05-09T13:59:44+00:00

Currently, io_ticks is accounted based on sampling, specifically update_io_ticks() will always account io_ticks by 1 jiffies from bdev_start_io_acct()/blk_account_io_start(), and the result can be inaccurate, for example(HZ is 250): Test script: fio -filename=/dev/sda -bs=4k -rw=write -direct=1 -name=test -thinktime=4ms Test result: util is about 90%, while the disk is really idle. This behaviour is introduced by commit 5b18b5a73760 ("block: delete part_round_stats and switch to less precise counting"), however, there was a key point that is missed that this patch also improve performance a lot: Before the commit: part_round_stats: if (part->stamp != now) stats |= 1; part_in_flight() -> there can be lots of task here in 1 jiffies. part_round_stats_single() __part_stat_add() part->stamp = now; After the commit: update_io_ticks: stamp = part->bd_stamp; if (time_after(now, stamp)) if (try_cmpxchg()) __part_stat_add() -> only one task can reach here in 1 jiffies. Hence in order to account io_ticks precisely, we only need to know if there are IO inflight at most once in one jiffies. Noted that for rq-based device, iterating tags should not be used here because 'tags->lock' is grabbed in blk_mq_find_and_get_req(), hence part_stat_lock_inc/dec() and part_in_flight() is used to trace inflight. The additional overhead is quite little: - per cpu add/dec for each IO for rq-based device; - per cpu sum for each jiffies; And it's verified by null-blk that there are no performance degration under heavy IO pressure. Fixes: 5b18b5a73760 ("block: delete part_round_stats and switch to less precise counting") Signed-off-by: Yu Kuai Link: https://lore.kernel.org/r/20240509123717.3223892-2-yukuai1@huaweicloud.com Signed-off-by: Jens Axboe