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Subject[PATCH 1/4] UIO: hold a reference to the device's owner while the device is open
Date
Otherwise the device might just disappear while /dev/uioX is being used
which results in an Oops.

Signed-off-by: Uwe Kleine-König <Uwe.Kleine-Koenig@digi.com>
---
drivers/uio/uio.c | 40 +++++++++++++++++++++++-----------------
1 files changed, 23 insertions(+), 17 deletions(-)
diff --git a/drivers/uio/uio.c b/drivers/uio/uio.c
index 1175908..005fc55 100644
--- a/drivers/uio/uio.c
+++ b/drivers/uio/uio.c
@@ -301,25 +301,35 @@ static int uio_open(struct inode *inode, struct file *filep)
if (!idev)
return -ENODEV;

+ if (!try_module_get(idev->owner)) {
+ ret = -ENODEV;
+ goto err_module_get;
+ }
+
listener = kmalloc(sizeof(*listener), GFP_KERNEL);
- if (!listener)
- return -ENOMEM;
+ if (!listener) {
+ ret = -ENOMEM;
+ goto err_alloc_listener;
+ }

listener->dev = idev;
listener->event_count = atomic_read(&idev->event);
filep->private_data = listener;

if (idev->info->open) {
- if (!try_module_get(idev->owner))
- return -ENODEV;
ret = idev->info->open(idev->info, inode);
- module_put(idev->owner);
- }
+ if (ret) {
+ kfree(listener);
+err_alloc_listener:

- if (ret)
- kfree(listener);
+ module_put(idev->owner);
+err_module_get:

- return ret;
+ return ret;
+ }
+ }
+
+ return 0;
}

static int uio_fasync(int fd, struct file *filep, int on)
@@ -336,12 +346,11 @@ static int uio_release(struct inode *inode, struct file *filep)
struct uio_listener *listener = filep->private_data;
struct uio_device *idev = listener->dev;

- if (idev->info->release) {
- if (!try_module_get(idev->owner))
- return -ENODEV;
+ if (idev->info->release)
ret = idev->info->release(idev->info, inode);
- module_put(idev->owner);
- }
+
+ module_put(idev->owner);
+
if (filep->f_flags & FASYNC)
ret = uio_fasync(-1, filep, 0);
kfree(listener);
@@ -510,10 +519,7 @@ static int uio_mmap(struct file *filep, struct vm_area_struct *vma)
return -EINVAL;

if (idev->info->mmap) {
- if (!try_module_get(idev->owner))
- return -ENODEV;
ret = idev->info->mmap(idev->info, vma);
- module_put(idev->owner);
return ret;
}

--
1.5.4.5
--
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