Re: [PATCH 1/1] tpm: fix cause of SMP stack traces -- updated version

Kylene Hall
2005-01-18T23:41:01Z

There were misplaced spinlock acquires and releases in the probe, close and release
paths which were causing might_sleep and schedule while atomic error messages accompanied
by stack traces when the kernel was compiled with SMP support. Bug reported by Reben Jenster
<ruben@hotheads.de>

Thanks,
Kylie

Signed-off-by: Kylene Hall <kjhall@us.ibm.com>
---
diff -uprN linux-2.6.10/drivers/char/tpm/tpm.c linux-2.6.10-tpm/drivers/char/tpm/tpm.c
--- linux-2.6.10/drivers/char/tpm/tpm.c 2005-01-18 18:10:16.000000000 -0600
+++ linux-2.6.10-tpm/drivers/char/tpm/tpm.c 2005-01-18 18:13:59.000000000 -0600
@@ -422,21 +421,24 @@ EXPORT_SYMBOL_GPL(tpm_open);
int tpm_release(struct inode *inode, struct file *file)
{
struct tpm_chip *chip = file->private_data;
+
+ file->private_data = NULL;

spin_lock(&driver_lock);
chip->num_opens--;
+ spin_unlock(&driver_lock);
+
down(&chip->timer_manipulation_mutex);
if (timer_pending(&chip->user_read_timer))
del_singleshot_timer_sync(&chip->user_read_timer);
else if (timer_pending(&chip->device_timer))
del_singleshot_timer_sync(&chip->device_timer);
up(&chip->timer_manipulation_mutex);
+
kfree(chip->data_buffer);
atomic_set(&chip->data_pending, 0);

pci_dev_put(chip->pci_dev);
- file->private_data = NULL;
- spin_unlock(&driver_lock);
return 0;
}

@@ -534,6 +536,8 @@ void __devexit tpm_remove(struct pci_dev

list_del(&chip->list);

+ spin_unlock(&driver_lock);
+
pci_set_drvdata(pci_dev, NULL);
misc_deregister(&chip->vendor->miscdev);

@@ -541,8 +545,6 @@ void __devexit tpm_remove(struct pci_dev
device_remove_file(&pci_dev->dev, &dev_attr_pcrs);
device_remove_file(&pci_dev->dev, &dev_attr_caps);

- spin_unlock(&driver_lock);
-
pci_disable_device(pci_dev);

dev_mask[chip->dev_num / 32] &= !(1 << (chip->dev_num % 32));
@@ -583,6 +585,7 @@ EXPORT_SYMBOL_GPL(tpm_pm_suspend);
int tpm_pm_resume(struct pci_dev *pci_dev)
{
struct tpm_chip *chip = pci_get_drvdata(pci_dev);
+
if (chip == NULL)
return -ENODEV;

@@ -650,15 +653,12 @@ dev_num_search_complete:
chip->vendor->miscdev.dev = &(pci_dev->dev);
chip->pci_dev = pci_dev_get(pci_dev);

- spin_lock(&driver_lock);
-
if (misc_register(&chip->vendor->miscdev)) {
dev_err(&chip->pci_dev->dev,
"unable to misc_register %s, minor %d\n",
chip->vendor->miscdev.name,
chip->vendor->miscdev.minor);
pci_dev_put(pci_dev);
- spin_unlock(&driver_lock);
kfree(chip);
dev_mask[i] &= !(1 << j);
return -ENODEV;
@@ -672,7 +672,6 @@ dev_num_search_complete:
device_create_file(&pci_dev->dev, &dev_attr_pcrs);
device_create_file(&pci_dev->dev, &dev_attr_caps);

- spin_unlock(&driver_lock);
return 0;
}