| Message ID | 20240917164820.143197-1-aha310510@gmail.com (mailing list archive) |
|---|---|
| State | Superseded |
| Headers | show |
| Series | usb: using mutex lock and supporting O_NONBLOCK flag in iowarrior_read() | expand |
On Wed, Sep 18, 2024 at 01:48:20AM +0900, Jeongjun Park wrote: > iowarrior_read() uses the iowarrior dev structure, but does not use any > lock on the structure. This can cause various bugs including data-races, > so it is more appropriate to use a mutex lock to safely protect the > iowarrior dev structure. When using a mutex lock, you should split the > branch to prevent blocking when the O_NONBLOCK flag is set. > > In addition, it is unnecessary to check for NULL on the iowarrior dev > structure obtained by reading file->private_data. Therefore, it is > better to remove the check. > > Fixes: 946b960d13c1 ("USB: add driver for iowarrior devices.") > Signed-off-by: Jeongjun Park <aha310510@gmail.com> > --- > drivers/usb/misc/iowarrior.c | 46 ++++++++++++++++++++++++++++-------- > 1 file changed, 36 insertions(+), 10 deletions(-) Hi, This is the friendly patch-bot of Greg Kroah-Hartman. You have sent him a patch that has triggered this response. He used to manually respond to these common problems, but in order to save his sanity (he kept writing the same thing over and over, yet to different people), I was created. Hopefully you will not take offence and will fix the problem in your patch and resubmit it so that it can be accepted into the Linux kernel tree. You are receiving this message because of the following common error(s) as indicated below: - This looks like a new version of a previously submitted patch, but you did not list below the --- line any changes from the previous version. Please read the section entitled "The canonical patch format" in the kernel file, Documentation/process/submitting-patches.rst for what needs to be done here to properly describe this. - You have marked a patch with a "Fixes:" tag for a commit that is in an older released kernel, yet you do not have a cc: stable line in the signed-off-by area at all, which means that the patch will not be applied to any older kernel releases. To properly fix this, please follow the documented rules in the Documentation/process/stable-kernel-rules.rst file for how to resolve this. If you wish to discuss this problem further, or you have questions about how to resolve this issue, please feel free to respond to this email and Greg will reply once he has dug out from the pending patches received from other developers. thanks, greg k-h's patch email bot
diff --git a/drivers/usb/misc/iowarrior.c b/drivers/usb/misc/iowarrior.c index 6d28467ce352..a513766b4985 100644 --- a/drivers/usb/misc/iowarrior.c +++ b/drivers/usb/misc/iowarrior.c @@ -277,28 +277,45 @@ static ssize_t iowarrior_read(struct file *file, char __user *buffer, struct iowarrior *dev; int read_idx; int offset; + int retval; dev = file->private_data; + if (file->f_flags & O_NONBLOCK) { + retval = mutex_trylock(&dev->mutex); + if (!retval) + return -EAGAIN; + } else { + retval = mutex_lock_interruptible(&dev->mutex); + if (retval) + return -ERESTARTSYS; + } + /* verify that the device wasn't unplugged */ - if (!dev || !dev->present) - return -ENODEV; + if (!dev->present) { + retval = -ENODEV; + goto exit; + } dev_dbg(&dev->interface->dev, "minor %d, count = %zd\n", dev->minor, count); /* read count must be packet size (+ time stamp) */ if ((count != dev->report_size) - && (count != (dev->report_size + 1))) - return -EINVAL; + && (count != (dev->report_size + 1))) { + retval = -EINVAL; + goto exit; + } /* repeat until no buffer overrun in callback handler occur */ do { atomic_set(&dev->overflow_flag, 0); if ((read_idx = read_index(dev)) == -1) { /* queue empty */ - if (file->f_flags & O_NONBLOCK) - return -EAGAIN; + if (file->f_flags & O_NONBLOCK) { + retval = -EAGAIN; + goto exit; + } else { //next line will return when there is either new data, or the device is unplugged int r = wait_event_interruptible(dev->read_wait, @@ -309,28 +326,37 @@ static ssize_t iowarrior_read(struct file *file, char __user *buffer, -1)); if (r) { //we were interrupted by a signal - return -ERESTART; + retval = -ERESTART; + goto exit; } if (!dev->present) { //The device was unplugged - return -ENODEV; + retval = -ENODEV; + goto exit; } if (read_idx == -1) { // Can this happen ??? - return 0; + retval = 0; + goto exit; } } } offset = read_idx * (dev->report_size + 1); if (copy_to_user(buffer, dev->read_queue + offset, count)) { - return -EFAULT; + retval = -EFAULT; + goto exit; } } while (atomic_read(&dev->overflow_flag)); read_idx = ++read_idx == MAX_INTERRUPT_BUFFER ? 0 : read_idx; atomic_set(&dev->read_idx, read_idx); + mutex_unlock(&dev->mutex); return count; + +exit: + mutex_unlock(&dev->mutex); + return retval; } /*
iowarrior_read() uses the iowarrior dev structure, but does not use any lock on the structure. This can cause various bugs including data-races, so it is more appropriate to use a mutex lock to safely protect the iowarrior dev structure. When using a mutex lock, you should split the branch to prevent blocking when the O_NONBLOCK flag is set. In addition, it is unnecessary to check for NULL on the iowarrior dev structure obtained by reading file->private_data. Therefore, it is better to remove the check. Fixes: 946b960d13c1 ("USB: add driver for iowarrior devices.") Signed-off-by: Jeongjun Park <aha310510@gmail.com> --- drivers/usb/misc/iowarrior.c | 46 ++++++++++++++++++++++++++++-------- 1 file changed, 36 insertions(+), 10 deletions(-) --