• Erez Shitrit's avatar
    IB/ipoib: Sync between remove_one to sysfs calls that use rtnl_lock · 69956d83
    Erez Shitrit authored
    In order to avoid deadlock between sysfs functions (like create/delete
    child) and remove_one (both of them are using the sysfs lock and
    rtnl_lock) the driver will use a state mutex for sync.
    
    That will fix traces as the following:
    schedule+0x3e/0x90
    kernfs_drain+0x75/0xf0
    ? wait_woken+0x90/0x90
    __kernfs_remove+0x12e/0x1c0
    kernfs_remove+0x25/0x40
    sysfs_remove_dir+0x57/0x90
    kobject_del+0x22/0x60
    device_del+0x195/0x230
     pm_runtime_set_memalloc_noio+0xac/0xf0
    netdev_unregister_kobject+0x71/0x80
    rollback_registered_many+0x205/0x2f0
    rollback_registered+0x31/0x40
    unregister_netdevice_queue+0x58/0xb0
    unregister_netdev+0x20/0x30
    ipoib_remove_one+0xb7/0x240 [ib_ipoib]
    ib_unregister_device+0xbc/0x1b0 [ib_core]
    ib_unregister_mad_agent+0x29/0x30 [ib_core]
    mlx4_ib_remove+0x67/0x280 [mlx4_ib]
    INFO: task echo:24082 blocked for more than 120 seconds.
    Tainted: G           OE   4.1.12-37.5.1.el6uek.x86_64 #2
    "echo 0 > /proc/sys/kernel/hung_task_timeout_secs" disables this
    message.
    Call Trace:
    schedule+0x3e/0x90
    schedule_preempt_disabled+0xe/0x10
    __mutex_lock_slowpath+0x95/0x110
    ? _rcu_barrier+0x177/0x220
    mutex_lock+0x23/0x40
    rtnl_lock+0x15/0x20
    netdev_run_todo+0x81/0x1f0
    rtnl_unlock+0xe/0x10
    ipoib_vlan_delete+0x12f/0x1c0 [ib_ipoib]
    delete_child+0x69/0x80 [ib_ipoib]
    dev_attr_store+0x20/0x30
    sysfs_kf_write+0x41/0x50
    Signed-off-by: default avatarErez Shitrit <erezsh@mellanox.com>
    Reviewed-by: default avatarAlex Vesker <valex@mellanox.com>
    Signed-off-by: default avatarLeon Romanovsky <leon@kernel.org>
    Signed-off-by: default avatarDoug Ledford <dledford@redhat.com>
    69956d83
ipoib.h 22.8 KB