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authorRichard MUSIL <richard.musil@st.com>2008-02-06 01:37:02 -0800
committerLinus Torvalds <torvalds@woody.linux-foundation.org>2008-02-06 10:41:04 -0800
commit5bd91f18be2fc0dd0384fbfca6d3cdd79a8050dd (patch)
treefe34a0db0cf9ee8194fda3c778a44d67e6c4b0a4 /drivers/char
parenteed4a2aba7ff6d8c40d3d55b81f80352765ffcee (diff)
tpm.c: fix crash during device removal
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>
Diffstat (limited to 'drivers/char')
-rw-r--r--drivers/char/tpm/tpm.c44
-rw-r--r--drivers/char/tpm/tpm.h2
2 files changed, 29 insertions, 17 deletions
diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index c88424a0c89..a5d8bcb4000 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -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);
@@ -1083,6 +1078,26 @@ 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
* this function the specific probe function has called pci_enable_device
@@ -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;
}
diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
index d15ccddc92e..e885148b4cf 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -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)