From f439696c81fcfe70ad46554fbec1c851bab9345a Mon Sep 17 00:00:00 2001 From: Ian Abbott Date: Wed, 17 Apr 2019 15:35:31 +0100 Subject: [PATCH] staging: comedi: don't release mutex too early in comedi_auto_config() `comedi_auto_config()` uses `dev->class_dev` for logging a kernel message after releasing `dev->mutex`. There is an unlikely possibility that the Comedi device `dev` will have been removed by the `COMEDI_DEVCONFIG` ioctl() command. Keep hold of the mutex until the kernel message has been sent to prevent that. The function can call `comedi_release_hardware_device()` on error. In that case, the mutex must be unlocked before that. Signed-off-by: Ian Abbott Signed-off-by: Greg Kroah-Hartman --- drivers/staging/comedi/drivers.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/drivers/staging/comedi/drivers.c b/drivers/staging/comedi/drivers.c index 5a32b8fc000e..b7b9e48d4303 100644 --- a/drivers/staging/comedi/drivers.c +++ b/drivers/staging/comedi/drivers.c @@ -1059,12 +1059,12 @@ int comedi_auto_config(struct device *hardware_device, ret = driver->auto_attach(dev, context); if (ret >= 0) ret = comedi_device_postconfig(dev); - mutex_unlock(&dev->mutex); if (ret < 0) { dev_warn(hardware_device, "driver '%s' failed to auto-configure device.\n", driver->driver_name); + mutex_unlock(&dev->mutex); comedi_release_hardware_device(hardware_device); } else { /* @@ -1074,6 +1074,7 @@ int comedi_auto_config(struct device *hardware_device, dev_info(dev->class_dev, "driver '%s' has successfully auto-configured '%s'.\n", driver->driver_name, dev->board_name); + mutex_unlock(&dev->mutex); } return ret; }