On Fri, 12 Dec 2014, Mika Westerberg wrote: > 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. Applied to for-3.19/upstream-fixes, thanks for fixing it. -- Jiri Kosina SUSE Labs -- To unsubscribe from this list: send the line "unsubscribe linux-input" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
