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    SubjectRe: [PATCH 4.19 108/125] USB: yurex: Fix bad gfp argument
    On Wed, Sep 02, 2020 at 02:58:27PM +0200, Pavel Machek wrote:
    > Hi!
    >
    > > The syzbot fuzzer identified a bug in the yurex driver: It passes
    > > GFP_KERNEL as a memory-allocation flag to usb_submit_urb() at a time
    > > when its state is TASK_INTERRUPTIBLE, not TASK_RUNNING:
    >
    > Yeah, and instead of fixing the bug, patch papers over it, reducing
    > reliability of the driver in the process.
    >
    > > This patch changes the call to use GFP_ATOMIC instead of GFP_KERNEL.
    >
    > Fixing it properly should be as simple as moving prepare_to_wait down,
    > no?

    Sigh. That never occurred to me, but of course it is right.

    Acked-by: Alan Stern <stern@rowland.harvard.edu>

    Alan Stern

    > Signed-off-by: Pavel Machek (CIP) <pavel@denx.de>
    >
    > diff --git a/drivers/usb/misc/yurex.c b/drivers/usb/misc/yurex.c
    > index 785080f79073..5fbbb57e6e95 100644
    > --- a/drivers/usb/misc/yurex.c
    > +++ b/drivers/usb/misc/yurex.c
    > @@ -489,10 +489,10 @@ static ssize_t yurex_write(struct file *file, const char __user *user_buffer,
    > }
    >
    > /* send the data as the control msg */
    > - prepare_to_wait(&dev->waitq, &wait, TASK_INTERRUPTIBLE);
    > dev_dbg(&dev->interface->dev, "%s - submit %c\n", __func__,
    > dev->cntl_buffer[0]);
    > - retval = usb_submit_urb(dev->cntl_urb, GFP_ATOMIC);
    > + retval = usb_submit_urb(dev->cntl_urb, GFP_KERNEL);
    > + prepare_to_wait(&dev->waitq, &wait, TASK_INTERRUPTIBLE);
    > if (retval >= 0)
    > timeout = schedule_timeout(YUREX_WRITE_TIMEOUT);
    > finish_wait(&dev->waitq, &wait);
    >
    >
    > Best regards,
    > Pavel
    >
    > --
    > (english) http://www.livejournal.com/~pavelmachek
    > (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


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