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misc: mic: Fix crash when MIC reset is invoked in RESET_FAILED state

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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 <sudeep.dutt@intel.com>
Signed-off-by: Ashutosh Dixit <ashutosh.dixit@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Ashutosh Dixit
2015-11-17 15:55:37 -08:00
committed by Greg Kroah-Hartman
parent 3f040887a8
commit f38e87e8c8
2 changed files with 11 additions and 4 deletions
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2
drivers/misc/mic/bus/cosm_bus.h
View File

@ -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;

13
drivers/misc/mic/cosm/cosm_main.c
View File

@ -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;