• Mika Westerberg's avatar
    HID: i2c-hid: Do not free buffers in i2c_hid_stop() · 5b44c53a
    Mika Westerberg authored
    When a hid driver that uses i2c-hid as transport is unloaded, the hid core
    will call i2c_hid_stop() which releases all the buffers associated with the
    device. This includes also the command buffer.
    
    Now, when the i2c-hid driver itself is unloaded it tries to power down the
    device by sending it PWR_SLEEP command. Since the command buffer is already
    released we get following crash:
    
     [   79.691459] BUG: unable to handle kernel NULL pointer dereference at           (null)
     [   79.691532] IP: [<ffffffffa05bc049>] __i2c_hid_command+0x49/0x310 [i2c_hid]
     ...
     [   79.693467] Call Trace:
     [   79.693494]  [<ffffffff810424e1>] ? __unmask_ioapic+0x21/0x30
     [   79.693537]  [<ffffffff81042855>] ? unmask_ioapic+0x25/0x40
     [   79.693581]  [<ffffffffa05bc35b>] ? i2c_hid_set_power+0x4b/0xa0 [i2c_hid]
     [   79.693632]  [<ffffffffa05bc3cf>] ? i2c_hid_runtime_resume+0x1f/0x30 [i2c_hid]
     [   79.693689]  [<ffffffff814c08fb>] ? __rpm_callback+0x2b/0x70
     [   79.693733]  [<ffffffff814c0961>] ? rpm_callback+0x21/0x90
     [   79.693776]  [<ffffffff814c0dec>] ? rpm_resume+0x41c/0x600
     [   79.693820]  [<ffffffff814c1e1c>] ? __pm_runtime_resume+0x4c/0x80
     [   79.693868]  [<ffffffff814b8588>] ? __device_release_driver+0x28/0x100
     [   79.693917]  [<ffffffff814b8d90>] ? driver_detach+0xa0/0xb0
     [   79.693959]  [<ffffffff814b82cc>] ? bus_remove_driver+0x4c/0xb0
     [   79.694006]  [<ffffffff810d1cfd>] ? SyS_delete_module+0x11d/0x1d0
     [   79.694054]  [<ffffffff8165f107>] ? int_signal+0x12/0x17
     [   79.694095]  [<ffffffff8165ee69>] ? system_call_fastpath+0x12/0x17
    
    Fix this so that we only free buffers when the i2c-hid driver itself is
    removed.
    
    Fixes: 34f439e4 ("HID: i2c-hid: add runtime PM support")
    Reported-by: default avatarGabriele Mazzotta <gabriele.mzt@gmail.com>
    Signed-off-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
    Reviewed-by: default avatarBenjamin Tissoires <benjamin.tissoires@redhat.com>
    Signed-off-by: default avatarJiri Kosina <jkosina@suse.cz>
    5b44c53a
i2c-hid.c 27.7 KB