This patch fixes the following crash seen when MIC reset is invoked in
RESET_FAILED state due to device_del being called a second time on an
already deleted device:
[<ffffffff813b2295>] device_del+0x45/0x1d0
[<ffffffff813b243e>] device_unregister+0x1e/0x60
[<ffffffffa040f1c2>] scif_unregister_device+0x12/0x20 [scif_bus]
[<ffffffffa042f75a>] cosm_stop+0xaa/0xe0 [mic_cosm]
[<ffffffffa042f844>] cosm_reset_trigger_work+0x14/0x20 [mic_cosm]
The fix consists in realizing that because cosm_reset changes the
state to MIC_RESETTING, cosm_stop needs the previous state, before it
changed to MIC_RESETTING, to decide whether a hw_ops->stop had
previously been issued. This is now provided in a new cosm_device
member cdev->prev_state.
Reviewed-by: Sudeep Dutt <[email protected]>
Signed-off-by: Ashutosh Dixit <[email protected]>
---
drivers/misc/mic/bus/cosm_bus.h | 2 ++
drivers/misc/mic/cosm/cosm_main.c | 13 +++++++++----
2 files changed, 11 insertions(+), 4 deletions(-)
diff --git a/drivers/misc/mic/bus/cosm_bus.h b/drivers/misc/mic/bus/cosm_bus.h
index f7c57f2..8b63418 100644
--- a/drivers/misc/mic/bus/cosm_bus.h
+++ b/drivers/misc/mic/bus/cosm_bus.h
@@ -30,6 +30,7 @@
* @attr_group: Pointer to list of sysfs attribute groups.
* @sdev: Device for sysfs entries.
* @state: MIC state.
+ * @prev_state: MIC state previous to MIC_RESETTING
* @shutdown_status: MIC status reported by card for shutdown/crashes.
* @shutdown_status_int: Internal shutdown status maintained by the driver
* @cosm_mutex: Mutex for synchronizing access to data structures.
@@ -55,6 +56,7 @@ struct cosm_device {
const struct attribute_group **attr_group;
struct device *sdev;
u8 state;
+ u8 prev_state;
u8 shutdown_status;
u8 shutdown_status_int;
struct mutex cosm_mutex;
diff --git a/drivers/misc/mic/cosm/cosm_main.c b/drivers/misc/mic/cosm/cosm_main.c
index 4b4b356..7005cb1 100644
--- a/drivers/misc/mic/cosm/cosm_main.c
+++ b/drivers/misc/mic/cosm/cosm_main.c
@@ -153,8 +153,10 @@ void cosm_stop(struct cosm_device *cdev, bool force)
* stop(..) calls device_unregister and will crash the system if
* called multiple times.
*/
- bool call_hw_ops = cdev->state != MIC_RESET_FAILED &&
- cdev->state != MIC_READY;
+ u8 state = cdev->state == MIC_RESETTING ?
+ cdev->prev_state : cdev->state;
+ bool call_hw_ops = state != MIC_RESET_FAILED &&
+ state != MIC_READY;
if (cdev->state != MIC_RESETTING)
cosm_set_state(cdev, MIC_RESETTING);
@@ -195,8 +197,11 @@ int cosm_reset(struct cosm_device *cdev)
mutex_lock(&cdev->cosm_mutex);
if (cdev->state != MIC_READY) {
- cosm_set_state(cdev, MIC_RESETTING);
- schedule_work(&cdev->reset_trigger_work);
+ if (cdev->state != MIC_RESETTING) {
+ cdev->prev_state = cdev->state;
+ cosm_set_state(cdev, MIC_RESETTING);
+ schedule_work(&cdev->reset_trigger_work);
+ }
} else {
dev_err(&cdev->dev, "%s %d MIC is READY\n", __func__, __LINE__);
rc = -EINVAL;
--
2.0.0.rc3.2.g998f840