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IB/hfi1: Do not free hfi1 cdev parent structure early 

The deletion of a cdev is not a fence for holding off references to the
structure. The driver attempts to delete the cdev and then proceeds to
free the parent structure, the hfi1_devdata, or dd. This can potentially
lead to a kernel panic in situations where a user has an FD for the cdev
open, and the pci device gets removed. If the user then closes the FD
there will be a NULL dereference when trying to do put on the cdev's
kobject.

Fix this by pointing the cdev's kobject.parent at a new kobject embedded
in its parent structure. Also take a reference when the device is opened
and put it back when it is closed.

Reviewed-by: Mitko Haralanov <mitko.haralanov@intel.com>
Signed-off-by: Ira Weiny <ira.weiny@intel.com>
Signed-off-by: Dennis Dalessandro <dennis.dalessandro@intel.com>
Signed-off-by: Doug Ledford <dledford@redhat.com>
This commit is contained in:
Dennis Dalessandro 2016-05-19 05:26:44 -07:00 committed by Doug Ledford
parent 8a1882ebd4
commit e11ffbd575
5 changed files with 31 additions and 6 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
drivers/staging/rdma/hfi1/device.c
View File

@ -60,7 +60,8 @@ static dev_t hfi1_dev;
int hfi1_cdev_init(int minor, const char *name,
const struct file_operations *fops,
struct cdev *cdev, struct device **devp,
bool user_accessible)
bool user_accessible,
struct kobject *parent)
{
const dev_t dev = MKDEV(MAJOR(hfi1_dev), minor);
struct device *device = NULL;
@ -68,6 +69,7 @@ int hfi1_cdev_init(int minor, const char *name,
cdev_init(cdev, fops);
cdev->owner = THIS_MODULE;
cdev->kobj.parent = parent;
kobject_set_name(&cdev->kobj, name);
ret = cdev_add(cdev, dev, 1);

3
drivers/staging/rdma/hfi1/device.h
View File

@ -50,7 +50,8 @@
int hfi1_cdev_init(int minor, const char *name,
const struct file_operations *fops,
struct cdev *cdev, struct device **devp,
bool user_accessible);
bool user_accessible,
struct kobject *parent);
void hfi1_cdev_cleanup(struct cdev *cdev, struct device **devp);
const char *class_name(void);
int __init dev_init(void);

15
drivers/staging/rdma/hfi1/file_ops.c
View File

@ -168,6 +168,13 @@ static inline int is_valid_mmap(u64 token)
static int hfi1_file_open(struct inode *inode, struct file *fp)
{
struct hfi1_devdata *dd = container_of(inode->i_cdev,
struct hfi1_devdata,
user_cdev);
/* Just take a ref now. Not all opens result in a context assign */
kobject_get(&dd->kobj);
/* The real work is performed later in assign_ctxt() */
fp->private_data = kzalloc(sizeof(struct hfi1_filedata), GFP_KERNEL);
if (fp->private_data) /* no cpu affinity by default */
@ -690,7 +697,9 @@ static int hfi1_file_close(struct inode *inode, struct file *fp)
{
struct hfi1_filedata *fdata = fp->private_data;
struct hfi1_ctxtdata *uctxt = fdata->uctxt;
struct hfi1_devdata *dd;
struct hfi1_devdata *dd = container_of(inode->i_cdev,
struct hfi1_devdata,
user_cdev);
unsigned long flags, *ev;
fp->private_data = NULL;
@ -699,7 +708,6 @@ static int hfi1_file_close(struct inode *inode, struct file *fp)
goto done;
hfi1_cdbg(PROC, "freeing ctxt %u:%u", uctxt->ctxt, fdata->subctxt);
dd = uctxt->dd;
mutex_lock(&hfi1_mutex);
flush_wc();
@ -765,6 +773,7 @@ static int hfi1_file_close(struct inode *inode, struct file *fp)
mutex_unlock(&hfi1_mutex);
hfi1_free_ctxtdata(dd, uctxt);
done:
kobject_put(&dd->kobj);
kfree(fdata);
return 0;
}
@ -1464,7 +1473,7 @@ static int user_add(struct hfi1_devdata *dd)
snprintf(name, sizeof(name), "%s_%d", class_name(), dd->unit);
ret = hfi1_cdev_init(dd->unit, name, &hfi1_file_ops,
&dd->user_cdev, &dd->user_device,
true);
true, &dd->kobj);
if (ret)
user_remove(dd);

1
drivers/staging/rdma/hfi1/hfi.h
View File

@ -1169,6 +1169,7 @@ struct hfi1_devdata {
atomic_t aspm_disabled_cnt;
struct hfi1_affinity *affinity;
struct kobject kobj;
};
/* 8051 firmware version helper */

14
drivers/staging/rdma/hfi1/init.c
View File

@ -989,8 +989,10 @@ static void release_asic_data(struct hfi1_devdata *dd)
dd->asic_data = NULL;
}
void hfi1_free_devdata(struct hfi1_devdata *dd)
static void __hfi1_free_devdata(struct kobject *kobj)
{
struct hfi1_devdata *dd =
container_of(kobj, struct hfi1_devdata, kobj);
unsigned long flags;
spin_lock_irqsave(&hfi1_devs_lock, flags);
@ -1007,6 +1009,15 @@ void hfi1_free_devdata(struct hfi1_devdata *dd)
rvt_dealloc_device(&dd->verbs_dev.rdi);
}
static struct kobj_type hfi1_devdata_type = {
.release = __hfi1_free_devdata,
};
void hfi1_free_devdata(struct hfi1_devdata *dd)
{
kobject_put(&dd->kobj);
}
/*
* Allocate our primary per-unit data structure. Must be done via verbs
* allocator, because the verbs cleanup process both does cleanup and
@ -1102,6 +1113,7 @@ struct hfi1_devdata *hfi1_alloc_devdata(struct pci_dev *pdev, size_t extra)
&pdev->dev,
"Could not alloc cpulist info, cpu affinity might be wrong\n");
}
kobject_init(&dd->kobj, &hfi1_devdata_type);
return dd;
bail: