• Dan Williams's avatar
    [SCSI] fix hot unplug vs async scan race · 3b661a92
    Dan Williams authored
    The following crash results from cases where the end_device has been
    removed before scsi_sysfs_add_sdev has had a chance to run.
    
     BUG: unable to handle kernel NULL pointer dereference at 0000000000000098
     IP: [<ffffffff8115e100>] sysfs_create_dir+0x32/0xb6
     ...
     Call Trace:
      [<ffffffff8125e4a8>] kobject_add_internal+0x120/0x1e3
      [<ffffffff81075149>] ? trace_hardirqs_on+0xd/0xf
      [<ffffffff8125e641>] kobject_add_varg+0x41/0x50
      [<ffffffff8125e70b>] kobject_add+0x64/0x66
      [<ffffffff8131122b>] device_add+0x12d/0x63a
      [<ffffffff814b65ea>] ? _raw_spin_unlock_irqrestore+0x47/0x56
      [<ffffffff8107de15>] ? module_refcount+0x89/0xa0
      [<ffffffff8132f348>] scsi_sysfs_add_sdev+0x4e/0x28a
      [<ffffffff8132dcbb>] do_scan_async+0x9c/0x145
    
    ...teach scsi_sysfs_add_devices() to check for deleted devices() before
    trying to add them, and teach scsi_remove_target() how to remove targets
    that have not been added via device_add().
    
    Cc: <stable@vger.kernel.org>
    Reported-by: default avatarDariusz Majchrzak <dariusz.majchrzak@intel.com>
    Signed-off-by: default avatarDan Williams <dan.j.williams@intel.com>
    Signed-off-by: default avatarJames Bottomley <JBottomley@Parallels.com>
    3b661a92
scsi_sysfs.c 28.6 KB