• Sudeep Holla's avatar
    firmware: arm_scmi: provide the mandatory device release callback · 46edb8d1
    Sudeep Holla authored
    The device/driver model clearly mandates that bus driver that discover
    and allocate the device must set the release callback. This callback
    will be used to free the device after all references have gone away.
    
    scmi bus driver is missing the obvious callback which will result in
    the following warning if the device is unregistered:
    
    Device 'scmi_dev.1' does not have a release() function, it is broken and
    must be fixed. See Documentation/kobject.txt.
    WARNING at drivers/base/core.c:922 device_release+0x8c/0xa0
    Hardware name: ARM LTD Juno Development Platform BIOS EDK II Jan 21 2019
    Workqueue: events deferred_probe_work_func
    pstate: 60000005 (nZCv daif -PAN -UAO)
    pc : device_release+0x8c/0xa0
    lr : device_release+0x8c/0xa0
    Call trace:
     device_release+0x8c/0xa0
     kobject_put+0x8c/0x208
     device_unregister+0x30/0x78
     scmi_device_destroy+0x28/0x50
     scmi_probe+0x354/0x5b0
     platform_drv_probe+0x58/0xa8
     really_probe+0x2c4/0x3e8
     driver_probe_device+0x12c/0x148
     __device_attach_driver+0xac/0x150
     bus_for_each_drv+0x78/0xd8
     __device_attach+0xe0/0x168
     device_initial_probe+0x24/0x30
     bus_probe_device+0xa0/0xa8
     deferred_probe_work_func+0x8c/0xe0
     process_one_work+0x1f0/0x478
     worker_thread+0x22c/0x450
     kthread+0x134/0x138
     ret_from_fork+0x10/0x1c
    ---[ end trace 420bdb7f6af50937 ]---
    
    Fix the issue by providing scmi_device_release callback. We have
    everything required for device release already in scmi_device_destroy,
    so we just need to move freeing of the device to scmi_device_release.
    
    Fixes: 933c5044 ("firmware: arm_scmi: add scmi protocol bus to enumerate protocol devices")
    Signed-off-by: default avatarSudeep Holla <sudeep.holla@arm.com>
    Cc: stable@vger.kernel.org # 4.17+
    Signed-off-by: default avatarArnd Bergmann <arnd@arndb.de>
    46edb8d1
bus.c 4.96 KB