Messages in this thread Patch in this message | | | Date | Fri, 15 May 2015 19:19:21 +0800 | From | Pan Xinhui <> | Subject | [PATCH V2] atmel: fix a race between fw_load and data free |
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mxt_probe() may fail at last step, or we jsut unload mxt module soon. the queue_work scheduled by request_firmware_nowait may run later, and then access some data which is freed. To handle this issue, add fw_load_completion field in mxt_data. then we wait for it complete both in probe error path and mxt_remove().
here is the detail in probe, similar in remove.
module load: worker_thread: mxt_probe -> mxt_initialize -> request_firmware_nowait (schedule_work) | sysfs_create_group (fails) mxt_config_cb -> mxt_configure_objects (may access data freed) | err_free_object: some cleanup work, like free(data).
Signed-off-by: xinhui.pan <xinhuix.pan@intel.com> --- change in V2: use fw_load_completion instead of statics. fix a race both in mxt_remove and mxt_probe.
drivers/input/touchscreen/atmel_mxt_ts.c | 10 ++++++++++ 1 file changed, 10 insertions(+)
diff --git a/drivers/input/touchscreen/atmel_mxt_ts.c b/drivers/input/touchscreen/atmel_mxt_ts.c index 40b98dd..3da040d 100644 --- a/drivers/input/touchscreen/atmel_mxt_ts.c +++ b/drivers/input/touchscreen/atmel_mxt_ts.c @@ -313,6 +313,9 @@ struct mxt_data { /* for config update handling */ struct completion crc_completion; + + /* for fw load handling */ + struct completion fw_load_completion; }; static size_t mxt_obj_size(const struct mxt_object *obj) @@ -1982,8 +1985,10 @@ static int mxt_configure_objects(struct mxt_data *data, static void mxt_config_cb(const struct firmware *cfg, void *ctx) { + struct mxt_data *data = ctx; mxt_configure_objects(ctx, cfg); release_firmware(cfg); + complete(&data->fw_load_completion); } static int mxt_initialize(struct mxt_data *data) @@ -2556,6 +2561,7 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id) init_completion(&data->bl_completion); init_completion(&data->reset_completion); init_completion(&data->crc_completion); + init_completion(&data->fw_load_completion); error = request_threaded_irq(client->irq, NULL, mxt_interrupt, pdata->irqflags | IRQF_ONESHOT, @@ -2581,6 +2587,8 @@ static int mxt_probe(struct i2c_client *client, const struct i2c_device_id *id) return 0; err_free_object: + mxt_wait_for_completion(data, &data->fw_load_completion, + MXT_FW_RESET_TIME); mxt_free_input_device(data); mxt_free_object_table(data); err_free_irq: @@ -2594,6 +2602,8 @@ static int mxt_remove(struct i2c_client *client) { struct mxt_data *data = i2c_get_clientdata(client); + mxt_wait_for_completion(data, &data->fw_load_completion, + MXT_FW_RESET_TIME); sysfs_remove_group(&client->dev.kobj, &mxt_attr_group); free_irq(data->irq, data); mxt_free_input_device(data); -- 1.9.1
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