2
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mirror of https://github.com/edk2-porting/linux-next.git synced 2024-12-29 15:43:59 +08:00
linux-next/block
Tetsuo Handa dfbb3409b2 block: genhd: don't call blkdev_show() with major_names_lock held
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 1c500ad706 ("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>
2021-09-07 08:36:21 -06:00
..
partitions for-5.15/block-2021-08-30 2021-08-30 18:52:11 -07:00
badblocks.c treewide: Use fallthrough pseudo-keyword 2020-08-23 17:36:59 -05:00
bfq-cgroup.c block, bfq: merge bursts of newly-created queues 2021-03-25 10:50:07 -06:00
bfq-iosched.c block, bfq: honor already-setup queue merges 2021-09-02 06:36:58 -06:00
bfq-iosched.h block, bfq: cleanup the repeated declaration 2021-08-25 06:45:33 -06:00
bfq-wf2q.c block: Introduce IOPRIO_NR_LEVELS 2021-08-18 07:21:12 -06:00
bio-integrity.c block: use bvec_virt in bio_integrity_{process,free} 2021-08-16 10:50:32 -06:00
bio.c bio: fix kerneldoc documentation for bio_alloc_kiocb() 2021-09-03 07:42:13 -06:00
blk-cgroup-rwstat.c blk-cgroup: Fix the recursive blkg rwstat 2021-03-05 11:32:15 -07:00
blk-cgroup-rwstat.h blk-cgroup: separate out blkg_rwstat under CONFIG_BLK_CGROUP_RWSTAT 2019-11-07 12:28:13 -07:00
blk-cgroup.c for-5.15/block-2021-08-30 2021-08-30 18:52:11 -07:00
blk-core.c io_uring-bio-cache.5-2021-08-30 2021-08-30 19:30:30 -07:00
blk-crypto-fallback.c block: rename BIO_MAX_PAGES to BIO_MAX_VECS 2021-03-11 07:47:48 -07:00
blk-crypto-internal.h block: make blk_crypto_rq_bio_prep() able to fail 2020-10-05 10:47:43 -06:00
blk-crypto.c blk-crypto: fix check for too-large dun_bytes 2021-08-25 06:45:00 -06:00
blk-exec.c block: return errors from blk_execute_rq() 2021-06-30 15:35:45 -06:00
blk-flush.c blk-mq: fix is_flush_rq 2021-08-17 20:17:34 -06:00
blk-integrity.c block: return errors from blk_integrity_add 2021-08-23 12:55:45 -06:00
blk-ioc.c block: remove retry loop in ioc_release_fn() 2020-07-16 10:22:15 -06:00
blk-iocost.c for-5.15/block-2021-08-30 2021-08-30 18:52:11 -07:00
blk-iolatency.c for-5.15/block-2021-08-30 2021-08-30 18:52:11 -07:00
blk-ioprio.c block: Introduce the ioprio rq-qos policy 2021-06-21 15:03:40 -06:00
blk-ioprio.h block: Introduce the ioprio rq-qos policy 2021-06-21 15:03:40 -06:00
blk-lib.c block: export blk_next_bio() 2021-06-17 15:51:20 +02:00
blk-map.c block: use memcpy_from_bvec in bio_copy_kern_endio_read 2021-08-02 13:37:28 -06:00
blk-merge.c io_uring-bio-cache.5-2021-08-30 2021-08-30 19:30:30 -07:00
blk-mq-cpumap.c blk-mq: remove the calling of local_memory_node() 2020-10-20 07:08:17 -06:00
blk-mq-debugfs-zoned.c block: Cleanup license notice 2019-01-17 21:21:40 -07:00
blk-mq-debugfs.c block: Introduce the ioprio rq-qos policy 2021-06-21 15:03:40 -06:00
blk-mq-debugfs.h blk-mq: no need to check return value of debugfs_create functions 2019-06-13 03:00:30 -06:00
blk-mq-pci.c block: Fix blk_mq_*_map_queues() kernel-doc headers 2019-05-31 15:12:34 -06:00
blk-mq-rdma.c block: Fix blk_mq_*_map_queues() kernel-doc headers 2019-05-31 15:12:34 -06:00
blk-mq-sched.c blk-mq-sched: Fix blk_mq_sched_alloc_tags() error handling 2021-07-27 16:44:38 -06:00
blk-mq-sched.h blk: Fix lock inversion between ioc lock and bfqd lock 2021-06-24 18:43:55 -06:00
blk-mq-sysfs.c block: remove blk-mq-sysfs dead code 2021-08-02 13:37:29 -06:00
blk-mq-tag.c blk-mq: Use request queue-wide tags for tagset-wide sbitmap 2021-05-24 06:47:22 -06:00
blk-mq-tag.h blk-mq: Some tag allocation code refactoring 2021-05-24 06:47:22 -06:00
blk-mq-virtio.c blk-mq: Fix typo in comment 2020-03-17 20:55:21 +01:00
blk-mq.c for-5.15/block-2021-08-30 2021-08-30 18:52:11 -07:00
blk-mq.h blk: Fix lock inversion between ioc lock and bfqd lock 2021-06-24 18:43:55 -06:00
blk-pm.c scsi: block: Fix a race in the runtime power management code 2020-12-09 11:41:41 -05:00
blk-pm.h block: Remove unused blk_pm_*() function definitions 2021-02-22 06:33:48 -07:00
blk-rq-qos.c rq-qos: fix missed wake-ups in rq_qos_throttle try two 2021-06-08 15:12:57 -06:00
blk-rq-qos.h block: Introduce the ioprio rq-qos policy 2021-06-21 15:03:40 -06:00
blk-settings.c block: add an explicit ->disk backpointer to the request_queue 2021-08-23 12:54:31 -06:00
blk-stat.c blk-stat: make q->stats->lock irqsafe 2020-09-01 16:48:46 -06:00
blk-stat.h block: deactivate blk_stat timer in wbt_disable_default() 2018-12-12 06:47:51 -07:00
blk-sysfs.c block: call blk_register_queue earlier in device_add_disk 2021-08-23 12:55:45 -06:00
blk-throttle.c blk-throtl: optimize IOPS throttle for large IO scenarios 2021-08-14 19:14:56 -06:00
blk-timeout.c block: blk-timeout: delete duplicated word 2020-07-31 16:29:47 -06:00
blk-wbt.c block: add an explicit ->disk backpointer to the request_queue 2021-08-23 12:54:31 -06:00
blk-wbt.h blk-wbt: introduce a new disable state to prevent false positive by rwb_enabled() 2021-06-21 15:03:41 -06:00
blk-zoned.c blk-zoned: allow BLKREPORTZONE without CAP_SYS_ADMIN 2021-08-24 10:12:36 -06:00
blk.h io_uring-bio-cache.5-2021-08-30 2021-08-30 19:30:30 -07:00
bounce.c block: use memcpy_from_bvec in __blk_queue_bounce 2021-08-02 13:37:28 -06:00
bsg-lib.c block-5.14-2021-07-08 2021-07-09 12:05:33 -07:00
bsg.c block-5.14-2021-07-08 2021-07-09 12:05:33 -07:00
disk-events.c block: return errors from disk_alloc_events 2021-08-23 12:55:45 -06:00
elevator.c block: return ELEVATOR_DISCARD_MERGE if possible 2021-08-09 14:37:47 -06:00
genhd.c block: genhd: don't call blkdev_show() with major_names_lock held 2021-09-07 08:36:21 -06:00
holder.c block: add back the bd_holder_dir reference in bd_link_disk_holder 2021-08-20 21:14:26 -06:00
ioctl.c block: pass a gendisk to bdev_resize_partition 2021-08-12 10:31:36 -06:00
ioprio.c block: fix default IO priority handling 2021-08-18 07:23:15 -06:00
Kconfig block: make the block holder code optional 2021-08-09 11:50:42 -06:00
Kconfig.iosched Revert "block/mq-deadline: Add cgroup support" 2021-08-11 13:47:26 -06:00
keyslot-manager.c - Fix DM integrity's HMAC support to provide enhanced security of 2021-02-22 10:22:54 -08:00
kyber-iosched.c kyber: make trace_block_rq call consistent with documentation 2021-08-06 16:40:47 -06:00
Makefile for-5.15/block-2021-08-30 2021-08-30 18:52:11 -07:00
mq-deadline.c block/mq-deadline: Move dd_queued() to fix defined but not used warning 2021-09-02 06:34:45 -06:00
opal_proto.h block: sed-opal: Change the check condition for regular session validity 2020-03-12 08:00:10 -06:00
scsi_ioctl.c block-5.14-2021-07-08 2021-07-09 12:05:33 -07:00
sed-opal.c block: sed-opal: Change the check condition for regular session validity 2020-03-12 08:00:10 -06:00
t10-pi.c block: use bvec_kmap_local in t10_pi_type1_{prepare,complete} 2021-08-02 13:37:28 -06:00