From 5bd91f18be2fc0dd0384fbfca6d3cdd79a8050dd Mon Sep 17 00:00:00 2001 From: Richard MUSIL Date: Wed, 6 Feb 2008 01:37:02 -0800 Subject: [PATCH] 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 Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- drivers/char/tpm/tpm.c | 44 ++++++++++++++++++++++++++---------------- drivers/char/tpm/tpm.h | 2 ++ 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); @@ -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_.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; } 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) -- 2.41.1