[PATCH v1] USB: sisusbvga: avoid initializing device in open
From: Ayush <hidden>
Date: 2026-09-05 19:37:12
Also in:
lkml
Subsystem:
sis usb2vga driver, the rest, usb subsystem · Maintainers:
Thomas Winischhofer, Linus Torvalds, Greg Kroah-Hartman
The USB core holds minor_rwsem while invoking a USB character device's open callback. sisusb_open() can currently initialize the device while holding sisusb->lock, and that initialization performs synchronous USB I/O. High-speed devices are already initialized during probe. Treat a probe-time initialization failure as a probe failure instead of retrying initialization from open, so the open callback no longer performs blocking device initialization. Reported-by: syzbot+3bc656a9271e7c8a5c6b@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=3bc656a9271e7c8a5c6b Signed-off-by: Ayush <redacted> --- drivers/usb/misc/sisusbvga/sisusbvga.c | 29 ++++++++++++-------------- 1 file changed, 13 insertions(+), 16 deletions(-)
diff --git a/drivers/usb/misc/sisusbvga/sisusbvga.c b/drivers/usb/misc/sisusbvga/sisusbvga.c
index 3e75a7c24828..6723a65b12b8 100644
--- a/drivers/usb/misc/sisusbvga/sisusbvga.c
+++ b/drivers/usb/misc/sisusbvga/sisusbvga.c@@ -2223,20 +2223,10 @@ static int sisusb_open(struct inode *inode, struct file *file) } if (!sisusb->devinit) { - if (sisusb->sisusb_dev->speed == USB_SPEED_HIGH || - sisusb->sisusb_dev->speed >= USB_SPEED_SUPER) { - if (sisusb_init_gfxdevice(sisusb, 0)) { - mutex_unlock(&sisusb->lock); - dev_err(&sisusb->sisusb_dev->dev, - "Failed to initialize device\n"); - return -EIO; - } - } else { - mutex_unlock(&sisusb->lock); - dev_err(&sisusb->sisusb_dev->dev, - "Device not attached to USB 2.0 hub\n"); - return -EIO; - } + mutex_unlock(&sisusb->lock); + dev_err(&sisusb->sisusb_dev->dev, + "Device not initialized\n"); + return -EIO; } /* Increment usage count for our sisusb */
@@ -2880,9 +2870,16 @@ static int sisusb_probe(struct usb_interface *intf, if (dev->speed == USB_SPEED_HIGH || dev->speed >= USB_SPEED_SUPER) { int initscreen = 1; - if (sisusb_init_gfxdevice(sisusb, initscreen)) + + if (sisusb_init_gfxdevice(sisusb, initscreen)) { dev_err(&sisusb->sisusb_dev->dev, - "Failed to early initialize device\n"); + "Failed to early initialize device\n"); + sisusb->present = 0; + usb_set_intfdata(intf, NULL); + usb_put_dev(sisusb->sisusb_dev); + retval = -EIO; + goto error_4; + } } else dev_info(&sisusb->sisusb_dev->dev,
--
2.53.0