From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Gabriele Mazzotta , Mika Westerberg , Benjamin Tissoires , Jiri Kosina Subject: [PATCH 3.18 057/150] HID: i2c-hid: Do not free buffers in i2c_hid_stop() Date: Tue, 13 Jan 2015 23:22:08 -0800 Message-Id: <20150114072058.449596472@linuxfoundation.org> In-Reply-To: <20150114072055.842408181@linuxfoundation.org> References: <20150114072055.842408181@linuxfoundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-15 Sender: linux-kernel-owner@vger.kernel.org List-ID: 3.18-stable review patch. If anyone has any objections, please let me know. ------------------ From: Mika Westerberg commit 5b44c53aeb791757072be4a267255cedfff594fd upstream. 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: [] __i2c_hid_command+0x49/0x310 [i2c_hid] ... [ 79.693467] Call Trace: [ 79.693494] [] ? __unmask_ioapic+0x21/0x30 [ 79.693537] [] ? unmask_ioapic+0x25/0x40 [ 79.693581] [] ? i2c_hid_set_power+0x4b/0xa0 [i2c_hid] [ 79.693632] [] ? i2c_hid_runtime_resume+0x1f/0x30 [i2c_hid] [ 79.693689] [] ? __rpm_callback+0x2b/0x70 [ 79.693733] [] ? rpm_callback+0x21/0x90 [ 79.693776] [] ? rpm_resume+0x41c/0x600 [ 79.693820] [] ? __pm_runtime_resume+0x4c/0x80 [ 79.693868] [] ? __device_release_driver+0x28/0x100 [ 79.693917] [] ? driver_detach+0xa0/0xb0 [ 79.693959] [] ? bus_remove_driver+0x4c/0xb0 [ 79.694006] [] ? SyS_delete_module+0x11d/0x1d0 [ 79.694054] [] ? int_signal+0x12/0x17 [ 79.694095] [] ? system_call_fastpath+0x12/0x17 Fix this so that we only free buffers when the i2c-hid driver itself is removed. Fixes: 34f439e4afcd ("HID: i2c-hid: add runtime PM support") Reported-by: Gabriele Mazzotta Signed-off-by: Mika Westerberg Reviewed-by: Benjamin Tissoires Signed-off-by: Jiri Kosina Signed-off-by: Greg Kroah-Hartman --- drivers/hid/i2c-hid/i2c-hid.c | 5 ----- 1 file changed, 5 deletions(-) --- a/drivers/hid/i2c-hid/i2c-hid.c +++ b/drivers/hid/i2c-hid/i2c-hid.c @@ -706,12 +706,7 @@ static int i2c_hid_start(struct hid_devi static void i2c_hid_stop(struct hid_device *hid) { - struct i2c_client *client = hid->driver_data; - struct i2c_hid *ihid = i2c_get_clientdata(client); - hid->claimed = 0; - - i2c_hid_free_buffers(ihid); } static int i2c_hid_open(struct hid_device *hid)