• Dan Williams's avatar
    block: fix ext_dev_lock lockdep report · 96ebd858
    Dan Williams authored
    commit 4d66e5e9 upstream.
    
     =================================
     [ INFO: inconsistent lock state ]
     4.1.0-rc7+ #217 Tainted: G           O
     ---------------------------------
     inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.
     swapper/6/0 [HC0[0]:SC1[1]:HE1:SE0] takes:
      (ext_devt_lock){+.?...}, at: [<ffffffff8143a60c>] blk_free_devt+0x3c/0x70
     {SOFTIRQ-ON-W} state was registered at:
       [<ffffffff810bf6b1>] __lock_acquire+0x461/0x1e70
       [<ffffffff810c1947>] lock_acquire+0xb7/0x290
       [<ffffffff818ac3a8>] _raw_spin_lock+0x38/0x50
       [<ffffffff8143a07d>] blk_alloc_devt+0x6d/0xd0  <-- take the lock in process context
    [..]
      [<ffffffff810bf64e>] __lock_acquire+0x3fe/0x1e70
      [<ffffffff810c00ad>] ? __lock_acquire+0xe5d/0x1e70
      [<ffffffff810c1947>] lock_acquire+0xb7/0x290
      [<ffffffff8143a60c>] ? blk_free_devt+0x3c/0x70
      [<ffffffff818ac3a8>] _raw_spin_lock+0x38/0x50
      [<ffffffff8143a60c>] ? blk_free_devt+0x3c/0x70
      [<ffffffff8143a60c>] blk_free_devt+0x3c/0x70    <-- take the lock in softirq
      [<ffffffff8143bfec>] part_release+0x1c/0x50
      [<ffffffff8158edf6>] device_release+0x36/0xb0
      [<ffffffff8145ac2b>] kobject_cleanup+0x7b/0x1a0
      [<ffffffff8145aad0>] kobject_put+0x30/0x70
      [<ffffffff8158f147>] put_device+0x17/0x20
      [<ffffffff8143c29c>] delete_partition_rcu_cb+0x16c/0x180
      [<ffffffff8143c130>] ? read_dev_sector+0xa0/0xa0
      [<ffffffff810e0e0f>] rcu_process_callbacks+0x2ff/0xa90
      [<ffffffff810e0dcf>] ? rcu_process_callbacks+0x2bf/0xa90
      [<ffffffff81067e2e>] __do_softirq+0xde/0x600
    
    Neil sees this in his tests and it also triggers on pmem driver unbind
    for the libnvdimm tests.  This fix is on top of an initial fix by Keith
    for incorrect usage of mutex_lock() in this path: 2da78092 "block:
    Fix dev_t minor allocation lifetime".  Both this and 2da78092 are
    candidates for -stable.
    
    Fixes: 2da78092 ("block: Fix dev_t minor allocation lifetime")
    Cc: Keith Busch <keith.busch@intel.com>
    Reported-by: default avatarNeilBrown <neilb@suse.de>
    Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
    Signed-off-by: default avatarJens Axboe <axboe@fb.com>
    Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
    96ebd858
genhd.c 44.2 KB