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2021-11-15blk-mq: cancel blk-mq dispatch work in both blk_cleanup_queue and disk_release()Ming Lei
For avoiding to slow down queue destroy, we don't call blk_mq_quiesce_queue() in blk_cleanup_queue(), instead of delaying to cancel dispatch work in blk_release_queue(). However, this way has caused kernel oops[1], reported by Changhui. The log shows that scsi_device can be freed before running blk_release_queue(), which is expected too since scsi_device is released after the scsi disk is closed and the scsi_device is removed. Fixes the issue by canceling blk-mq dispatch work in both blk_cleanup_queue() and disk_release(): 1) when disk_release() is run, the disk has been closed, and any sync dispatch activities have been done, so canceling dispatch work is enough to quiesce filesystem I/O dispatch activity. 2) in blk_cleanup_queue(), we only focus on passthrough request, and passthrough request is always explicitly allocated & freed by its caller, so once queue is frozen, all sync dispatch activity for passthrough request has been done, then it is enough to just cancel dispatch work for avoiding any dispatch activity. [1] kernel panic log [12622.769416] BUG: kernel NULL pointer dereference, address: 0000000000000300 [12622.777186] #PF: supervisor read access in kernel mode [12622.782918] #PF: error_code(0x0000) - not-present page [12622.788649] PGD 0 P4D 0 [12622.791474] Oops: 0000 [#1] PREEMPT SMP PTI [12622.796138] CPU: 10 PID: 744 Comm: kworker/10:1H Kdump: loaded Not tainted 5.15.0+ #1 [12622.804877] Hardware name: Dell Inc. PowerEdge R730/0H21J3, BIOS 1.5.4 10/002/2015 [12622.813321] Workqueue: kblockd blk_mq_run_work_fn [12622.818572] RIP: 0010:sbitmap_get+0x75/0x190 [12622.823336] Code: 85 80 00 00 00 41 8b 57 08 85 d2 0f 84 b1 00 00 00 45 31 e4 48 63 cd 48 8d 1c 49 48 c1 e3 06 49 03 5f 10 4c 8d 6b 40 83 f0 01 <48> 8b 33 44 89 f2 4c 89 ef 0f b6 c8 e8 fa f3 ff ff 83 f8 ff 75 58 [12622.844290] RSP: 0018:ffffb00a446dbd40 EFLAGS: 00010202 [12622.850120] RAX: 0000000000000001 RBX: 0000000000000300 RCX: 0000000000000004 [12622.858082] RDX: 0000000000000006 RSI: 0000000000000082 RDI: ffffa0b7a2dfe030 [12622.866042] RBP: 0000000000000004 R08: 0000000000000001 R09: ffffa0b742721334 [12622.874003] R10: 0000000000000008 R11: 0000000000000008 R12: 0000000000000000 [12622.881964] R13: 0000000000000340 R14: 0000000000000000 R15: ffffa0b7a2dfe030 [12622.889926] FS: 0000000000000000(0000) GS:ffffa0baafb40000(0000) knlGS:0000000000000000 [12622.898956] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 [12622.905367] CR2: 0000000000000300 CR3: 0000000641210001 CR4: 00000000001706e0 [12622.913328] Call Trace: [12622.916055] <TASK> [12622.918394] scsi_mq_get_budget+0x1a/0x110 [12622.922969] __blk_mq_do_dispatch_sched+0x1d4/0x320 [12622.928404] ? pick_next_task_fair+0x39/0x390 [12622.933268] __blk_mq_sched_dispatch_requests+0xf4/0x140 [12622.939194] blk_mq_sched_dispatch_requests+0x30/0x60 [12622.944829] __blk_mq_run_hw_queue+0x30/0xa0 [12622.949593] process_one_work+0x1e8/0x3c0 [12622.954059] worker_thread+0x50/0x3b0 [12622.958144] ? rescuer_thread+0x370/0x370 [12622.962616] kthread+0x158/0x180 [12622.966218] ? set_kthread_struct+0x40/0x40 [12622.970884] ret_from_fork+0x22/0x30 [12622.974875] </TASK> [12622.977309] Modules linked in: scsi_debug rpcsec_gss_krb5 auth_rpcgss nfsv4 dns_resolver nfs lockd grace fscache netfs sunrpc dm_multipath intel_rapl_msr intel_rapl_common dell_wmi_descriptor sb_edac rfkill video x86_pkg_temp_thermal intel_powerclamp dcdbas coretemp kvm_intel kvm mgag200 irqbypass i2c_algo_bit rapl drm_kms_helper ipmi_ssif intel_cstate intel_uncore syscopyarea sysfillrect sysimgblt fb_sys_fops pcspkr cec mei_me lpc_ich mei ipmi_si ipmi_devintf ipmi_msghandler acpi_power_meter drm fuse xfs libcrc32c sr_mod cdrom sd_mod t10_pi sg ixgbe ahci libahci crct10dif_pclmul crc32_pclmul crc32c_intel libata megaraid_sas ghash_clmulni_intel tg3 wdat_wdt mdio dca wmi dm_mirror dm_region_hash dm_log dm_mod [last unloaded: scsi_debug] Reported-by: ChanghuiZhong <czhong@redhat.com> Cc: Christoph Hellwig <hch@lst.de> Cc: "Martin K. Petersen" <martin.petersen@oracle.com> Cc: Bart Van Assche <bvanassche@acm.org> Cc: linux-scsi@vger.kernel.org Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20211116014343.610501-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-09block: add __must_check for *add_disk*() callersLuis Chamberlain
Now that we have done a spring cleaning on all drivers and added error checking / handling, let's keep it that way and ensure no new drivers fail to stick with it. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Bart Van Assche <bvanassche@acm.org> Link: https://lore.kernel.org/r/20211110002949.999380-1-mcgrof@kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-09Merge tag 'for-5.16/drivers-2021-11-09' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull more block driver updates from Jens Axboe: - Last series adding error handling support for add_disk() in drivers. After this one, and once the SCSI side has been merged, we can finally annotate add_disk() as must_check. (Luis) - bcache fixes (Coly) - zram fixes (Ming) - ataflop locking fix (Tetsuo) - nbd fixes (Ye, Yu) - MD merge via Song - Cleanup (Yang) - sysfs fix (Guoqing) - Misc fixes (Geert, Wu, luo) * tag 'for-5.16/drivers-2021-11-09' of git://git.kernel.dk/linux-block: (34 commits) bcache: Revert "bcache: use bvec_virt" ataflop: Add missing semicolon to return statement floppy: address add_disk() error handling on probe ataflop: address add_disk() error handling on probe block: update __register_blkdev() probe documentation ataflop: remove ataflop_probe_lock mutex mtd/ubi/block: add error handling support for add_disk() block/sunvdc: add error handling support for add_disk() z2ram: add error handling support for add_disk() nvdimm/pmem: use add_disk() error handling nvdimm/pmem: cleanup the disk if pmem_release_disk() is yet assigned nvdimm/blk: add error handling support for add_disk() nvdimm/blk: avoid calling del_gendisk() on early failures nvdimm/btt: add error handling support for add_disk() nvdimm/btt: use goto error labels on btt_blk_init() loop: Remove duplicate assignments drbd: Fix double free problem in drbd_create_device nvdimm/btt: do not call del_gendisk() if not needed bcache: fix use-after-free problem in bcache_device_free() zram: replace fsync_bdev with sync_blockdev ...
2021-11-09Merge tag 'for-5.16/block-2021-11-09' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block fixes from Jens Axboe: - Set of fixes for the batched tag allocation (Ming, me) - add_disk() error handling fix (Luis) - Nested queue quiesce fixes (Ming) - Shared tags init error handling fix (Ye) - Misc cleanups (Jean, Ming, me) * tag 'for-5.16/block-2021-11-09' of git://git.kernel.dk/linux-block: nvme: wait until quiesce is done scsi: make sure that request queue queiesce and unquiesce balanced scsi: avoid to quiesce sdev->request_queue two times blk-mq: add one API for waiting until quiesce is done blk-mq: don't free tags if the tag_set is used by other device in queue initialztion block: fix device_add_disk() kobject_create_and_add() error handling block: ensure cached plug request matches the current queue block: move queue enter logic into blk_mq_submit_bio() block: make bio_queue_enter() fast-path available inline block: split request allocation components into helpers block: have plug stored requests hold references to the queue blk-mq: update hctx->nr_active in blk_mq_end_request_batch() blk-mq: add RQF_ELV debug entry blk-mq: only try to run plug merge if request has same queue with incoming bio block: move RQF_ELV setting into allocators dm: don't stop request queue after the dm device is suspended block: replace always false argument with 'false' block: assign correct tag before doing prefetch of request blk-mq: fix redundant check of !e expression
2021-11-04block: fix device_add_disk() kobject_create_and_add() error handlingLuis Chamberlain
Commit 83cbce957446 ("block: add error handling for device_add_disk / add_disk") added error handling to device_add_disk(), however the goto label for the kobject_create_and_add() failure did not set the return value correctly, and so we can end up in a situation where kobject_create_and_add() fails but we report success. Fixes: 83cbce957446 ("block: add error handling for device_add_disk / add_disk") Reported-by: kernel test robot <lkp@intel.com> Reported-by: Dan Carpenter <dan.carpenter@oracle.com> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20211103164023.1384821-1-mcgrof@kernel.org [axboe: fold in followup fix from Wu Bo <wubo40@huawei.com>] Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-04block: update __register_blkdev() probe documentationLuis Chamberlain
__register_blkdev() is used to register a probe callback, and that callback is typically used to call add_disk(). Now that we are able to capture errors for add_disk(), we need to fix those probe calls where add_disk() fails and clean up resources. We don't extend the probe call to return the error given: 1) we'd have to always special-case the case where the disk was already present, as otherwise concurrent requests to open an existing block device would fail, and this would be a userspace visible change 2) the error from ilookup() on blkdev_get_no_open() is sufficient 3) The only thing the probe call is used for is to support pre-devtmpfs, pre-udev semantics that want to create disks when their pre-created device node is accessed, and so we don't care for failures on probe there. Expand documentation for the probe callback to ensure users cleanup resources if add_disk() is used and to clarify this interface may be removed in the future. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> Link: https://lore.kernel.org/r/20211103230437.1639990-12-mcgrof@kernel.org Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-11-01Merge tag 'for-5.16/bdev-size-2021-10-29' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull bdev size cleanups from Jens Axboe: "Clean up the bdev size handling with new bdev_nr_bytes() helper" * tag 'for-5.16/bdev-size-2021-10-29' of git://git.kernel.dk/linux-block: (34 commits) partitions/ibm: use bdev_nr_sectors instead of open coding it partitions/efi: use bdev_nr_bytes instead of open coding it block/ioctl: use bdev_nr_sectors and bdev_nr_bytes block: cache inode size in bdev udf: use sb_bdev_nr_blocks reiserfs: use sb_bdev_nr_blocks ntfs: use sb_bdev_nr_blocks jfs: use sb_bdev_nr_blocks ext4: use sb_bdev_nr_blocks block: add a sb_bdev_nr_blocks helper block: use bdev_nr_bytes instead of open coding it in blkdev_fallocate squashfs: use bdev_nr_bytes instead of open coding it reiserfs: use bdev_nr_bytes instead of open coding it pstore/blk: use bdev_nr_bytes instead of open coding it ntfs3: use bdev_nr_bytes instead of open coding it nilfs2: use bdev_nr_bytes instead of open coding it nfs/blocklayout: use bdev_nr_bytes instead of open coding it jfs: use bdev_nr_bytes instead of open coding it hfsplus: use bdev_nr_sectors instead of open coding it hfs: use bdev_nr_sectors instead of open coding it ...
2021-11-01Merge tag 'for-5.16/block-2021-10-29' of git://git.kernel.dk/linux-blockLinus Torvalds
Pull block updates from Jens Axboe: - mq-deadline accounting improvements (Bart) - blk-wbt timer fix (Andrea) - Untangle the block layer includes (Christoph) - Rework the poll support to be bio based, which will enable adding support for polling for bio based drivers (Christoph) - Block layer core support for multi-actuator drives (Damien) - blk-crypto improvements (Eric) - Batched tag allocation support (me) - Request completion batching support (me) - Plugging improvements (me) - Shared tag set improvements (John) - Concurrent queue quiesce support (Ming) - Cache bdev in ->private_data for block devices (Pavel) - bdev dio improvements (Pavel) - Block device invalidation and block size improvements (Xie) - Various cleanups, fixes, and improvements (Christoph, Jackie, Masahira, Tejun, Yu, Pavel, Zheng, me) * tag 'for-5.16/block-2021-10-29' of git://git.kernel.dk/linux-block: (174 commits) blk-mq-debugfs: Show active requests per queue for shared tags block: improve readability of blk_mq_end_request_batch() virtio-blk: Use blk_validate_block_size() to validate block size loop: Use blk_validate_block_size() to validate block size nbd: Use blk_validate_block_size() to validate block size block: Add a helper to validate the block size block: re-flow blk_mq_rq_ctx_init() block: prefetch request to be initialized block: pass in blk_mq_tags to blk_mq_rq_ctx_init() block: add rq_flags to struct blk_mq_alloc_data block: add async version of bio_set_polled block: kill DIO_MULTI_BIO block: kill unused polling bits in __blkdev_direct_IO() block: avoid extra iter advance with async iocb block: Add independent access ranges support blk-mq: don't issue request directly in case that current is to be blocked sbitmap: silence data race warning blk-cgroup: synchronize blkg creation against policy deactivation block: refactor bio_iov_bvec_set() block: add single bio async direct IO helper ...
2021-10-26block: drain queue after disk is removed from sysfsMing Lei
Before removing disk from sysfs, userspace still may change queue via sysfs, such as switching elevator or setting wbt latency, both may reinitialize wbt, then the warning in blk_free_queue_stats() will be triggered since rq_qos_exit() is moved to del_gendisk(). Fixes the issue by moving draining queue & tearing down after disk is removed from sysfs, at that time no one can come into queue's store()/show(). Reported-by: Yi Zhang <yi.zhang@redhat.com> Tested-by: Yi Zhang <yi.zhang@redhat.com> Fixes: 8e141f9eb803 ("block: drain file system I/O on del_gendisk") Signed-off-by: Ming Lei <ming.lei@redhat.com> Link: https://lore.kernel.org/r/20211026101204.2897166-1-ming.lei@redhat.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-21block: Add invalidate_disk() helper to invalidate the gendiskXie Yongji
To hide internal implementation and simplify some driver code, this adds a helper to invalidate the gendisk. It will clean the gendisk's associated buffer/page caches and reset its internal states. Signed-off-by: Xie Yongji <xieyongji@bytedance.com> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210922123711.187-2-xieyongji@bytedance.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-19block: move bdev_read_only() into the headerJens Axboe
This is called for every write in the fast path, move it inline next to get_disk_ro() which is called internally. Reviewed-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Chaitanya Kulkarni <kch@nvidia.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18block: cache inode size in bdevJens Axboe
Reading the inode size brings in a new cacheline for IO submit, and it's in the hot path being checked for every single IO. When doing millions of IOs per core per second, this is noticeable overhead. Cache the nr_sectors in the bdev itself. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18block: convert the rest of block to bdev_get_queuePavel Begunkov
Convert bdev->bd_disk->queue to bdev_get_queue(), it's uses a cached queue pointer and so is faster. Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/addf6ea988c04213697ba3684c853e4ed7642a39.1634219547.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18block: cache request queue in bdevPavel Begunkov
There are tons of places where we need to get a request_queue only having bdev, which turns into bdev->bd_disk->queue. There are probably a hundred of such places considering inline helpers, and enough of them are in hot paths. Cache queue pointer in struct block_device and make use of it in bdev_get_queue(). Signed-off-by: Pavel Begunkov <asml.silence@gmail.com> Link: https://lore.kernel.org/r/a3bfaecdd28956f03629d0ca5c63ebc096e1c809.1634219547.git.asml.silence@gmail.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-18block: drop unused includes in <linux/genhd.h>Christoph Hellwig
Drop various include not actually used in genhd.h itself, and move the remaning includes closer together. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/20210920123328.1399408-15-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-17block: warn when putting the final reference on a registered diskChristoph Hellwig
Warn when the last reference on a live disk is put without calling del_gendisk first. There are some BDI related bug reports that look like a case of this, so make sure we have the proper instrumentation to catch it. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20211014130231.1468538-1-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-15block: keep q_usage_counter in atomic mode after del_gendiskChristoph Hellwig
Don't switch back to percpu mode to avoid the double RCU grace period when tearing down SCSI devices. After removing the disk only passthrough commands can be send anyway. Suggested-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: Darrick J. Wong <djwong@kernel.org> Link: https://lore.kernel.org/r/20210929071241.934472-6-hch@lst.de Tested-by: Yi Zhang <yi.zhang@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-15block: drain file system I/O on del_gendiskChristoph Hellwig
Instead of delaying draining of file system I/O related items like the blk-qos queues, the integrity read workqueue and timeouts only when the request_queue is removed, do that when del_gendisk is called. This is important for SCSI where the upper level drivers that control the gendisk are separate entities, and the disk can be freed much earlier than the request_queue, or can even be unbound without tearing down the queue. Fixes: edb0872f44ec ("block: move the bdi from the request_queue to the gendisk") Reported-by: Ming Lei <ming.lei@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: Darrick J. Wong <djwong@kernel.org> Link: https://lore.kernel.org/r/20210929071241.934472-5-hch@lst.de Tested-by: Yi Zhang <yi.zhang@redhat.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-10-02block: genhd: fix double kfree() in __alloc_disk_node()Tetsuo Handa
syzbot is reporting use-after-free read at bdev_free_inode() [1], for kfree() from __alloc_disk_node() is called before bdev_free_inode() (which is called after RCU grace period) reads bdev->bd_disk and calls kfree(bdev->bd_disk). Fix use-after-free read followed by double kfree() problem by making sure that bdev->bd_disk is NULL when calling iput(). Link: https://syzkaller.appspot.com/bug?extid=8281086e8a6fbfbd952a [1] Reported-by: syzbot <syzbot+8281086e8a6fbfbd952a@syzkaller.appspotmail.com> Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Reviewed-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/e6dd13c5-8db0-4392-6e78-a42ee5d2a1c4@i-love.sakura.ne.jp Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-09-07block: genhd: don't call blkdev_show() with major_names_lock heldTetsuo Handa
If CONFIG_BLK_DEV_LOOP && CONFIG_MTD (at least; there might be other combinations), lockdep complains circular locking dependency at __loop_clr_fd(), for major_names_lock serves as a locking dependency aggregating hub across multiple block modules. ====================================================== WARNING: possible circular locking dependency detected 5.14.0+ #757 Tainted: G E ------------------------------------------------------ systemd-udevd/7568 is trying to acquire lock: ffff88800f334d48 ((wq_completion)loop0){+.+.}-{0:0}, at: flush_workqueue+0x70/0x560 but task is already holding lock: ffff888014a7d4a0 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x4d/0x400 [loop] which lock already depends on the new lock. the existing dependency chain (in reverse order) is: -> #6 (&lo->lo_mutex){+.+.}-{3:3}: lock_acquire+0xbe/0x1f0 __mutex_lock_common+0xb6/0xe10 mutex_lock_killable_nested+0x17/0x20 lo_open+0x23/0x50 [loop] blkdev_get_by_dev+0x199/0x540 blkdev_open+0x58/0x90 do_dentry_open+0x144/0x3a0 path_openat+0xa57/0xda0 do_filp_open+0x9f/0x140 do_sys_openat2+0x71/0x150 __x64_sys_openat+0x78/0xa0 do_syscall_64+0x3d/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #5 (&disk->open_mutex){+.+.}-{3:3}: lock_acquire+0xbe/0x1f0 __mutex_lock_common+0xb6/0xe10 mutex_lock_nested+0x17/0x20 bd_register_pending_holders+0x20/0x100 device_add_disk+0x1ae/0x390 loop_add+0x29c/0x2d0 [loop] blk_request_module+0x5a/0xb0 blkdev_get_no_open+0x27/0xa0 blkdev_get_by_dev+0x5f/0x540 blkdev_open+0x58/0x90 do_dentry_open+0x144/0x3a0 path_openat+0xa57/0xda0 do_filp_open+0x9f/0x140 do_sys_openat2+0x71/0x150 __x64_sys_openat+0x78/0xa0 do_syscall_64+0x3d/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #4 (major_names_lock){+.+.}-{3:3}: lock_acquire+0xbe/0x1f0 __mutex_lock_common+0xb6/0xe10 mutex_lock_nested+0x17/0x20 blkdev_show+0x19/0x80 devinfo_show+0x52/0x60 seq_read_iter+0x2d5/0x3e0 proc_reg_read_iter+0x41/0x80 vfs_read+0x2ac/0x330 ksys_read+0x6b/0xd0 do_syscall_64+0x3d/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #3 (&p->lock){+.+.}-{3:3}: lock_acquire+0xbe/0x1f0 __mutex_lock_common+0xb6/0xe10 mutex_lock_nested+0x17/0x20 seq_read_iter+0x37/0x3e0 generic_file_splice_read+0xf3/0x170 splice_direct_to_actor+0x14e/0x350 do_splice_direct+0x84/0xd0 do_sendfile+0x263/0x430 __se_sys_sendfile64+0x96/0xc0 do_syscall_64+0x3d/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae -> #2 (sb_writers#3){.+.+}-{0:0}: lock_acquire+0xbe/0x1f0 lo_write_bvec+0x96/0x280 [loop] loop_process_work+0xa68/0xc10 [loop] process_one_work+0x293/0x480 worker_thread+0x23d/0x4b0 kthread+0x163/0x180 ret_from_fork+0x1f/0x30 -> #1 ((work_completion)(&lo->rootcg_work)){+.+.}-{0:0}: lock_acquire+0xbe/0x1f0 process_one_work+0x280/0x480 worker_thread+0x23d/0x4b0 kthread+0x163/0x180 ret_from_fork+0x1f/0x30 -> #0 ((wq_completion)loop0){+.+.}-{0:0}: validate_chain+0x1f0d/0x33e0 __lock_acquire+0x92d/0x1030 lock_acquire+0xbe/0x1f0 flush_workqueue+0x8c/0x560 drain_workqueue+0x80/0x140 destroy_workqueue+0x47/0x4f0 __loop_clr_fd+0xb4/0x400 [loop] blkdev_put+0x14a/0x1d0 blkdev_close+0x1c/0x20 __fput+0xfd/0x220 task_work_run+0x69/0xc0 exit_to_user_mode_prepare+0x1ce/0x1f0 syscall_exit_to_user_mode+0x26/0x60 do_syscall_64+0x4c/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae other info that might help us debug this: Chain exists of: (wq_completion)loop0 --> &disk->open_mutex --> &lo->lo_mutex Possible unsafe locking scenario: CPU0 CPU1 ---- ---- lock(&lo->lo_mutex); lock(&disk->open_mutex); lock(&lo->lo_mutex); lock((wq_completion)loop0); *** DEADLOCK *** 2 locks held by systemd-udevd/7568: #0: ffff888012554128 (&disk->open_mutex){+.+.}-{3:3}, at: blkdev_put+0x4c/0x1d0 #1: ffff888014a7d4a0 (&lo->lo_mutex){+.+.}-{3:3}, at: __loop_clr_fd+0x4d/0x400 [loop] stack backtrace: CPU: 0 PID: 7568 Comm: systemd-udevd Tainted: G E 5.14.0+ #757 Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 02/27/2020 Call Trace: dump_stack_lvl+0x79/0xbf print_circular_bug+0x5d6/0x5e0 ? stack_trace_save+0x42/0x60 ? save_trace+0x3d/0x2d0 check_noncircular+0x10b/0x120 validate_chain+0x1f0d/0x33e0 ? __lock_acquire+0x953/0x1030 ? __lock_acquire+0x953/0x1030 __lock_acquire+0x92d/0x1030 ? flush_workqueue+0x70/0x560 lock_acquire+0xbe/0x1f0 ? flush_workqueue+0x70/0x560 flush_workqueue+0x8c/0x560 ? flush_workqueue+0x70/0x560 ? sched_clock_cpu+0xe/0x1a0 ? drain_workqueue+0x41/0x140 drain_workqueue+0x80/0x140 destroy_workqueue+0x47/0x4f0 ? blk_mq_freeze_queue_wait+0xac/0xd0 __loop_clr_fd+0xb4/0x400 [loop] ? __mutex_unlock_slowpath+0x35/0x230 blkdev_put+0x14a/0x1d0 blkdev_close+0x1c/0x20 __fput+0xfd/0x220 task_work_run+0x69/0xc0 exit_to_user_mode_prepare+0x1ce/0x1f0 syscall_exit_to_user_mode+0x26/0x60 do_syscall_64+0x4c/0xb0 entry_SYSCALL_64_after_hwframe+0x44/0xae RIP: 0033:0x7f0fd4c661f7 Code: 00 00 f7 d8 64 89 02 48 c7 c0 ff ff ff ff eb b7 0f 1f 00 f3 0f 1e fa 64 8b 04 25 18 00 00 00 85 c0 75 10 b8 03 00 00 00 0f 05 <48> 3d 00 f0 ff ff 77 41 c3 48 83 ec 18 89 7c 24 0c e8 13 fc ff ff RSP: 002b:00007ffd1c9e9fd8 EFLAGS: 00000246 ORIG_RAX: 0000000000000003 RAX: 0000000000000000 RBX: 00007f0fd46be6c8 RCX: 00007f0fd4c661f7 RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000006 RBP: 0000000000000006 R08: 000055fff1eaf400 R09: 0000000000000000 R10: 00007f0fd46be6c8 R11: 0000000000000246 R12: 0000000000000000 R13: 0000000000000000 R14: 0000000000002f08 R15: 00007ffd1c9ea050 Commit 1c500ad706383f1a ("loop: reduce the loop_ctl_mutex scope") is for breaking "loop_ctl_mutex => &lo->lo_mutex" dependency chain. But enabling a different block module results in forming circular locking dependency due to shared major_names_lock mutex. The simplest fix is to call probe function without holding major_names_lock [1], but Christoph Hellwig does not like such idea. Therefore, instead of holding major_names_lock in blkdev_show(), introduce a different lock for blkdev_show() in order to break "sb_writers#$N => &p->lock => major_names_lock" dependency chain. Link: https://lkml.kernel.org/r/b2af8a5b-3c1b-204e-7f56-bea0b15848d6@i-love.sakura.ne.jp [1] Signed-off-by: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Link: https://lore.kernel.org/r/18a02da2-0bf3-550e-b071-2b4ab13c49f0@i-love.sakura.ne.jp Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-24block: refine the disk_live check in del_gendiskChristoph Hellwig
hidden gendisks will never be marked live. Fixes: 40b3a52ffc5b ("block: add a sanity check for a live disk in del_gendisk") Reported-by: Bruno Goncalves <bgoncalv@redhat.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210824144310.1487816-1-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-24block: remove CONFIG_DEBUG_BLOCK_EXT_DEVTChristoph Hellwig
This might have been a neat debug aid when the extended dev_t was added, but that time is long gone. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210824075216.1179406-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-24block: remove a pointless call to MINOR() in device_add_diskChristoph Hellwig
blk_alloc_ext_minor already returns just a minor number, so no need to mask the high bits. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210824075216.1179406-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23block: add error handling for device_add_disk / add_diskLuis Chamberlain
Properly unwind on errors in device_add_disk. This is the initial work as drivers are not converted yet, which will follow in separate patches. Signed-off-by: Luis Chamberlain <mcgrof@kernel.org> [hch: major rebase. All bugs are probably mine] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://lore.kernel.org/r/20210818144542.19305-10-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23block: call blk_register_queue earlier in device_add_diskChristoph Hellwig
Ensure that all the sysfs bits are set up before bdev_add is called, as that will make the upcomding error handling much easier. However this means the call to disk_update_readahead has to be split as that requires a bdi. Also remove various sanity checks that don't make sense now that blk_register_queue only has a single caller. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210818144542.19305-7-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23block: call blk_integrity_add earlier in device_add_diskChristoph Hellwig
Doing all the sysfs file creation before adding the bdev and thus allowing it to be opened will simplify the about to be added error handling. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://lore.kernel.org/r/20210818144542.19305-6-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23block: create the bdi link earlier in device_add_diskChristoph Hellwig
This will simplify error handling going forward. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://lore.kernel.org/r/20210818144542.19305-5-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23block: call bdev_add later in device_add_diskChristoph Hellwig
Once bdev_add is called userspace can open the block device. Ensure that the struct device, which is used for refcounting of the disk besides various other things, is fully setup at that point. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://lore.kernel.org/r/20210818144542.19305-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23block: fold register_disk into device_add_diskChristoph Hellwig
There is no real reason these should be separate. Also simplify the groups assignment a bit. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210818144542.19305-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23block: add a sanity check for a live disk in del_gendiskChristoph Hellwig
Add a sanity check to del_gendisk to do nothing when the disk wasn't successfully added. This papers over the complete lack of add_disk error handling, which is about to get fixed gradually. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Link: https://lore.kernel.org/r/20210818144542.19305-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23block: add an explicit ->disk backpointer to the request_queueChristoph Hellwig
Replace the magic lookup through the kobject tree with an explicit backpointer, given that the device model links are set up and torn down at times when I/O is still possible, leading to potential NULL or invalid pointer dereferences. Fixes: edb0872f44ec ("block: move the bdi from the request_queue to the gendisk") Reported-by: syzbot <syzbot+aa0801b6b32dca9dda82@syzkaller.appspotmail.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Tested-by: Sven Schnelle <svens@linux.ibm.com> Link: https://lore.kernel.org/r/20210816134624.GA24234@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23block: hold a request_queue reference for the lifetime of struct gendiskChristoph Hellwig
Acquire the queue ref dropped in disk_release in __blk_alloc_disk so any allocate gendisk always has a queue reference. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210816131910.615153-9-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23block: pass a request_queue to __blk_alloc_diskChristoph Hellwig
Pass in a request_queue and assign disk->queue in __blk_alloc_disk to ensure struct gendisk always has a valid ->queue pointer. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210816131910.615153-8-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23block: remove the minors argument to __alloc_disk_nodeChristoph Hellwig
This was a leftover from the legacy alloc_disk interface. Switch the scsi ULPs and dasd to set ->minors directly like all other drivers and remove the argument. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Stefan Haberland <sth@linux.ibm.com> [dasd] Link: https://lore.kernel.org/r/20210816131910.615153-7-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-23block: cleanup the lockdep handling in *alloc_diskChristoph Hellwig
Pass the lockdep name to the low-level __blk_alloc_disk helper and hardcode the name for it given that the number of minors or node_id are not very useful information. While this passes a pointless argument for non-lockdep builds that is not really an issue as disk allocation is a probe time only slow path. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210816131910.615153-5-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-16block: ensure the bdi is freed after inode_detach_wbChristoph Hellwig
inode_detach_wb references the "main" bdi of the inode. With the recent change to move the bdi from the request_queue to the gendisk this causes a guaranteed use after free when using certain cgroup configurations. The big itself is older through as any non-default inode reference (e.g. an open file descriptor) could have injected this use after free even before that. Fixes: 52ebea749aae ("writeback: make backing_dev_info host cgroup-specific bdi_writebacks") Reported-by: Qian Cai <quic_qiancai@quicinc.com> Reported-by: syzbot <syzbot+1fb38bb7d3ce0fa3e1c4@syzkaller.appspotmail.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210816122614.601358-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-16block: free the extended dev_t minor laterChristoph Hellwig
The dev_t is used as the inode hash, so we should only released it once then block device inode is gone from the inode cache. Move it to bdev_free_inode to ensure that. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210816122614.601358-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-12block: remove GENHD_FL_UPChristoph Hellwig
Just check inode_unhashed on the whole device bdev inode instead, and provide a helper to check for that information. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210809064028.1198327-9-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-09block: move the bdi from the request_queue to the gendiskChristoph Hellwig
The backing device information only makes sense for file system I/O, and thus belongs into the gendisk and not the lower level request_queue structure. Move it there. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Johannes Thumshirn <johannes.thumshirn@wdc.com> Link: https://lore.kernel.org/r/20210809141744.1203023-5-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-09block: remove support for delayed queue registrationsChristoph Hellwig
Now that device mapper has been changed to register the disk once it is fully ready all this code is unused. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Link: https://lore.kernel.org/r/20210804094147.459763-9-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-09block: support delayed holder registrationChristoph Hellwig
device mapper needs to register holders before it is ready to do I/O. Currently it does so by registering the disk early, which can leave the disk and queue in a weird half state where the queue is registered with the disk, except for sysfs and the elevator. And this state has been a bit promlematic before, and will get more so when sorting out the responsibilities between the queue and the disk. Support registering holders on an initialized but not registered disk instead by delaying the sysfs registration until the disk is registered. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Mike Snitzer <snitzer@redhat.com> Link: https://lore.kernel.org/r/20210804094147.459763-5-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-09block: look up holders by bdevChristoph Hellwig
Invert they way the holder relations are tracked. This very slightly reduces the memory overhead for partitioned devices. Signed-off-by: Christoph Hellwig <hch@lst.de> Link: https://lore.kernel.org/r/20210804094147.459763-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-02block: export diskseq in sysfsMatteo Croce
Add a new sysfs handle to export the new diskseq value. Place it in <sysfs>/block/<disk>/diskseq and document it. $ grep . /sys/class/block/*/diskseq /sys/class/block/loop0/diskseq:13 /sys/class/block/loop1/diskseq:14 /sys/class/block/loop2/diskseq:5 /sys/class/block/loop3/diskseq:6 /sys/class/block/ram0/diskseq:1 /sys/class/block/ram1/diskseq:2 /sys/class/block/vda/diskseq:7 Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Matteo Croce <mcroce@microsoft.com> Tested-by: Luca Boccassi <bluca@debian.org> Link: https://lore.kernel.org/r/20210712230530.29323-5-mcroce@linux.microsoft.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-02block: export the diskseq in ueventsMatteo Croce
Export the newly introduced diskseq in uevents: $ udevadm info /sys/class/block/* |grep -e DEVNAME -e DISKSEQ E: DEVNAME=/dev/loop0 E: DISKSEQ=1 E: DEVNAME=/dev/loop1 E: DISKSEQ=2 E: DEVNAME=/dev/loop2 E: DISKSEQ=3 E: DEVNAME=/dev/loop3 E: DISKSEQ=4 E: DEVNAME=/dev/loop4 E: DISKSEQ=5 E: DEVNAME=/dev/loop5 E: DISKSEQ=6 E: DEVNAME=/dev/loop6 E: DISKSEQ=7 E: DEVNAME=/dev/loop7 E: DISKSEQ=8 E: DEVNAME=/dev/nvme0n1 E: DISKSEQ=9 E: DEVNAME=/dev/nvme0n1p1 E: DISKSEQ=9 E: DEVNAME=/dev/nvme0n1p2 E: DISKSEQ=9 E: DEVNAME=/dev/nvme0n1p3 E: DISKSEQ=9 E: DEVNAME=/dev/nvme0n1p4 E: DISKSEQ=9 E: DEVNAME=/dev/nvme0n1p5 E: DISKSEQ=9 E: DEVNAME=/dev/sda E: DISKSEQ=10 E: DEVNAME=/dev/sda1 E: DISKSEQ=10 E: DEVNAME=/dev/sda2 E: DISKSEQ=10 Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Matteo Croce <mcroce@microsoft.com> Tested-by: Luca Boccassi <bluca@debian.org> Link: https://lore.kernel.org/r/20210712230530.29323-3-mcroce@linux.microsoft.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-02block: add disk sequence numberMatteo Croce
Associating uevents with block devices in userspace is difficult and racy: the uevent netlink socket is lossy, and on slow and overloaded systems has a very high latency. Block devices do not have exclusive owners in userspace, any process can set one up (e.g. loop devices). Moreover, device names can be reused (e.g. loop0 can be reused again and again). A userspace process setting up a block device and watching for its events cannot thus reliably tell whether an event relates to the device it just set up or another earlier instance with the same name. Being able to set a UUID on a loop device would solve the race conditions. But it does not allow to derive orderings from uevents: if you see a uevent with a UUID that does not match the device you are waiting for, you cannot tell whether it's because the right uevent has not arrived yet, or it was already sent and you missed it. So you cannot tell whether you should wait for it or not. Associating a unique, monotonically increasing sequential number to the lifetime of each block device, which can be retrieved with an ioctl immediately upon setting it up, allows to solve the race conditions with uevents, and also allows userspace processes to know whether they should wait for the uevent they need or if it was dropped and thus they should move on. Additionally, increment the disk sequence number when the media change, i.e. on DISK_EVENT_MEDIA_CHANGE event. Reviewed-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Matteo Croce <mcroce@microsoft.com> Tested-by: Luca Boccassi <bluca@debian.org> Link: https://lore.kernel.org/r/20210712230530.29323-2-mcroce@linux.microsoft.com Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-02block: remove disk_name()Christoph Hellwig
Remove the disk_name function now that all users are gone. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://lore.kernel.org/r/20210727062518.122108-7-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-02block: use the %pg format specifier in show_partitionChristoph Hellwig
Simplify printing the partition name by using the %pg format specifier that is equivalent to a bdevname call. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://lore.kernel.org/r/20210727062518.122108-4-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-02block: use the %pg format specifier in printk_all_partitionsChristoph Hellwig
Simplify printing the partition name by using the %pg format specifier that is equivalent to a bdevname call. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://lore.kernel.org/r/20210727062518.122108-3-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-02block: reduce stack usage in diskstats_showAbd-Alrhman Masalkhi
I have compiled the kernel with a cross compiler "hppa-linux-gnu-" v9.3.0 on x86-64 host machine. I got the following warning: block/genhd.c: In function ‘diskstats_show’: block/genhd.c:1227:1: warning: the frame size of 1688 bytes is larger than 1280 bytes [-Wframe-larger-than=] 1227 | } By Reduced the stack footprint by using the %pg printk specifier instead of disk_name to remove the need for the on-stack buffer. Signed-off-by: Abd-Alrhman Masalkhi <abd.masalkhi@gmail.com> Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Hannes Reinecke <hare@suse.de> Reviewed-by: Martin K. Petersen <martin.petersen@oracle.com> Link: https://lore.kernel.org/r/20210727062518.122108-2-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
2021-08-02block: remove bdputChristoph Hellwig
Now that we've stopped using inode references for anything meaninful in the block layer get rid of the helper to put it and just open code the call to iput on the block_device inode. Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: Josef Bacik <josef@toxicpanda.com> Reviewed-by: Chaitanya Kulkarni <ckulkarnilinux@gmail.com> Link: https://lore.kernel.org/r/20210722075402.983367-10-hch@lst.de Signed-off-by: Jens Axboe <axboe@kernel.dk>
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