From: Oliver Neukum Date: Tue, 1 Apr 2025 08:45:39 +0000 (+0200) Subject: USB: wdm: close race between wdm_open and wdm_wwan_port_stop X-Git-Tag: v6.15-rc4~21^2~6 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=c1846ed4eb527bdfe6b3b7dd2c78e2af4bf98f4f;p=thirdparty%2Fkernel%2Flinux.git USB: wdm: close race between wdm_open and wdm_wwan_port_stop Clearing WDM_WWAN_IN_USE must be the last action or we can open a chardev whose URBs are still poisoned Fixes: cac6fb015f71 ("usb: class: cdc-wdm: WWAN framework integration") Cc: stable Signed-off-by: Oliver Neukum Link: https://lore.kernel.org/r/20250401084749.175246-3-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman --- diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c index eb86d1c9b4a44..9c686751ddc10 100644 --- a/drivers/usb/class/cdc-wdm.c +++ b/drivers/usb/class/cdc-wdm.c @@ -726,7 +726,7 @@ static int wdm_open(struct inode *inode, struct file *file) rv = -EBUSY; goto out; } - + smp_rmb(); /* ordered against wdm_wwan_port_stop() */ rv = usb_autopm_get_interface(desc->intf); if (rv < 0) { dev_err(&desc->intf->dev, "Error autopm - %d\n", rv); @@ -868,8 +868,10 @@ static void wdm_wwan_port_stop(struct wwan_port *port) poison_urbs(desc); desc->manage_power(desc->intf, 0); clear_bit(WDM_READ, &desc->flags); - clear_bit(WDM_WWAN_IN_USE, &desc->flags); unpoison_urbs(desc); + smp_wmb(); /* ordered against wdm_open() */ + /* this must be last lest we open a poisoned device */ + clear_bit(WDM_WWAN_IN_USE, &desc->flags); } static void wdm_wwan_port_tx_complete(struct urb *urb)