6.6-stable review patch. If anyone has any objections, please let me know.
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From: Oliver Neukum oneukum@suse.com
commit c1846ed4eb527bdfe6b3b7dd2c78e2af4bf98f4f upstream.
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 stable@kernel.org Signed-off-by: Oliver Neukum oneukum@suse.com Link: https://lore.kernel.org/r/20250401084749.175246-3-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/class/cdc-wdm.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- 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, 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 ww 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)