From 30adce93d5c4a5a1ec29d9249e3fdfcc391d406b Mon Sep 17 00:00:00 2001 From: Xu Rao Date: Fri, 26 Jun 2026 14:46:17 +0800 Subject: [PATCH] usb: gadget: f_printer: take kref only for successful open printer_open() returns -EBUSY when the character device is already open, but it increments dev->kref regardless of the return value. VFS does not call ->release() for a failed open, so every rejected second open permanently leaks one reference. Move kref_get() into the successful-open branch. Fixes: e8d5f92b8d30 ("usb: gadget: function: printer: fix use-after-free in __lock_acquire") Cc: stable Signed-off-by: Xu Rao Link: https://patch.msgid.link/80295742B820DA9B+20260626064617.4090626-1-raoxu@uniontech.com Signed-off-by: Greg Kroah-Hartman --- drivers/usb/gadget/function/f_printer.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/usb/gadget/function/f_printer.c b/drivers/usb/gadget/function/f_printer.c index e4f7828ae75d..837f753d0cae 100644 --- a/drivers/usb/gadget/function/f_printer.c +++ b/drivers/usb/gadget/function/f_printer.c @@ -363,12 +363,11 @@ printer_open(struct inode *inode, struct file *fd) ret = 0; /* Change the printer status to show that it's on-line. */ dev->printer_status |= PRINTER_SELECTED; + kref_get(&dev->kref); } spin_unlock_irqrestore(&dev->lock, flags); - kref_get(&dev->kref); - return ret; }