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tpm.c: fix crash during device removal

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The clean up procedure now uses platform device "release" callback to
handle memory clean up.  For this purpose "release" function callback was
added to struct tpm_vendor_specific, so hw device driver provider can get
called when it is safe to remove all allocated resources.

This is supposed to fix a bug in device removal, where device while in
receive function (waiting on timeout) was prone to segfault, if the
tpm_chip struct was unallocated before the timeout expired (in
tpm_remove_hardware).

Acked-by: Marcel Selhorst <tpm@selhorst.net>
Cc: <stable@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Richard MUSIL 2008-02-06 01:37:02 -08:00 committed by Linus Torvalds
parent eed4a2aba7
commit 5bd91f18be
2 changed files with 29 additions and 17 deletions
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44
drivers/char/tpm/tpm.c
View File

@ -1031,18 +1031,13 @@ void tpm_remove_hardware(struct device *dev)
spin_unlock(&driver_lock);
dev_set_drvdata(dev, NULL);
misc_deregister(&chip->vendor.miscdev);
kfree(chip->vendor.miscdev.name);
sysfs_remove_group(&dev->kobj, chip->vendor.attr_group);
tpm_bios_log_teardown(chip->bios_dir);
clear_bit(chip->dev_num, dev_mask);
kfree(chip);
put_device(dev);
/* write it this way to be explicit (chip->dev == dev) */
put_device(chip->dev);
}
EXPORT_SYMBOL_GPL(tpm_remove_hardware);
@ -1082,6 +1077,26 @@ int tpm_pm_resume(struct device *dev)
}
EXPORT_SYMBOL_GPL(tpm_pm_resume);
/*
* Once all references to platform device are down to 0,
* release all allocated structures.
* In case vendor provided release function,
* call it too.
*/
static void tpm_dev_release(struct device *dev)
{
struct tpm_chip *chip = dev_get_drvdata(dev);
if (chip->vendor.release)
chip->vendor.release(dev);
chip->release(dev);
clear_bit(chip->dev_num, dev_mask);
kfree(chip->vendor.miscdev.name);
kfree(chip);
}
/*
* Called from tpm_<specific>.c probe function only for devices
* the driver has determined it should claim. Prior to calling
@ -1136,23 +1151,21 @@ struct tpm_chip *tpm_register_hardware(struct device *dev, const struct tpm_vend
chip->vendor.miscdev.parent = dev;
chip->dev = get_device(dev);
chip->release = dev->release;
dev->release = tpm_dev_release;
dev_set_drvdata(dev, chip);
if (misc_register(&chip->vendor.miscdev)) {
dev_err(chip->dev,
"unable to misc_register %s, minor %d\n",
chip->vendor.miscdev.name,
chip->vendor.miscdev.minor);
put_device(dev);
clear_bit(chip->dev_num, dev_mask);
kfree(chip);
kfree(devname);
put_device(chip->dev);
return NULL;
}
spin_lock(&driver_lock);
dev_set_drvdata(dev, chip);
list_add(&chip->list, &tpm_chip_list);
spin_unlock(&driver_lock);
@ -1160,10 +1173,7 @@ struct tpm_chip *tpm_register_hardware(struct device *dev, const struct tpm_vend
if (sysfs_create_group(&dev->kobj, chip->vendor.attr_group)) {
list_del(&chip->list);
misc_deregister(&chip->vendor.miscdev);
put_device(dev);
clear_bit(chip->dev_num, dev_mask);
kfree(chip);
kfree(devname);
put_device(chip->dev);
return NULL;
}

2
drivers/char/tpm/tpm.h
View File

@ -74,6 +74,7 @@ struct tpm_vendor_specific {
int (*send) (struct tpm_chip *, u8 *, size_t);
void (*cancel) (struct tpm_chip *);
u8 (*status) (struct tpm_chip *);
void (*release) (struct device *);
struct miscdevice miscdev;
struct attribute_group *attr_group;
struct list_head list;
@ -106,6 +107,7 @@ struct tpm_chip {
struct dentry **bios_dir;
struct list_head list;
void (*release) (struct device *);
};
#define to_tpm_chip(n) container_of(n, struct tpm_chip, vendor)