3.16.80-rc1 review patch. If anyone has any objections, please let me know.
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From: Johan Hovold johan@kernel.org
commit b2fa7baee744fde746c17bc1860b9c6f5c2eebb7 upstream.
The driver was using its struct usb_device pointer as an inverted disconnected flag, but was setting it to NULL before making sure all completion handlers had run. This could lead to a NULL-pointer dereference in a number of dev_dbg statements in the completion handlers which relies on said pointer.
The pointer was also dereferenced unconditionally in a dev_dbg statement release() something which would lead to a NULL-deref whenever a device was disconnected before the final character-device close if debugging was enabled.
Fix this by unconditionally stopping all I/O and preventing resubmissions by poisoning the interrupt URBs at disconnect and using a dedicated disconnected flag.
This also makes sure that all I/O has completed by the time the disconnect callback returns.
Fixes: 1ef37c6047fe ("USB: adutux: remove custom debug macro and module parameter") Fixes: 66d4bc30d128 ("USB: adutux: remove custom debug macro") Signed-off-by: Johan Hovold johan@kernel.org Link: https://lore.kernel.org/r/20190925092913.8608-2-johan@kernel.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Ben Hutchings ben@decadent.org.uk --- drivers/usb/misc/adutux.c | 16 ++++++++++------ 1 file changed, 10 insertions(+), 6 deletions(-)
--- a/drivers/usb/misc/adutux.c +++ b/drivers/usb/misc/adutux.c @@ -80,6 +80,7 @@ struct adu_device { char serial_number[8];
int open_count; /* number of times this port has been opened */ + unsigned long disconnected:1;
char *read_buffer_primary; int read_buffer_length; @@ -121,7 +122,7 @@ static void adu_abort_transfers(struct a { unsigned long flags;
- if (dev->udev == NULL) + if (dev->disconnected) return;
/* shutdown transfer */ @@ -244,7 +245,7 @@ static int adu_open(struct inode *inode, }
dev = usb_get_intfdata(interface); - if (!dev || !dev->udev) { + if (!dev) { retval = -ENODEV; goto exit_no_device; } @@ -327,7 +328,7 @@ static int adu_release(struct inode *ino }
adu_release_internal(dev); - if (dev->udev == NULL) { + if (dev->disconnected) { /* the device was unplugged before the file was released */ if (!dev->open_count) /* ... and we're the last user */ adu_delete(dev); @@ -356,7 +357,7 @@ static ssize_t adu_read(struct file *fil return -ERESTARTSYS;
/* verify that the device wasn't unplugged */ - if (dev->udev == NULL) { + if (dev->disconnected) { retval = -ENODEV; pr_err("No device or device unplugged %d\n", retval); goto exit; @@ -521,7 +522,7 @@ static ssize_t adu_write(struct file *fi goto exit_nolock;
/* verify that the device wasn't unplugged */ - if (dev->udev == NULL) { + if (dev->disconnected) { retval = -ENODEV; pr_err("No device or device unplugged %d\n", retval); goto exit; @@ -801,11 +802,14 @@ static void adu_disconnect(struct usb_in
usb_deregister_dev(interface, &adu_class);
+ usb_poison_urb(dev->interrupt_in_urb); + usb_poison_urb(dev->interrupt_out_urb); + mutex_lock(&adutux_mutex); usb_set_intfdata(interface, NULL);
mutex_lock(&dev->mtx); /* not interruptible */ - dev->udev = NULL; /* poison */ + dev->disconnected = 1; mutex_unlock(&dev->mtx);
/* if the device is not opened, then we clean up right now */