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authorOliver Neukum <oneukum@suse.com>2024-03-14 12:50:48 +0100
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2024-03-26 14:56:33 +0100
commit339f83612f3a569b194680768b22bf113c26a29d (patch)
treeee684e37856195b5893dcdee01ae963e6fd0fee8 /drivers/usb/class
parent5d69a3b54e5a630c90d82a4c2bdce3d53dc78710 (diff)
usb: cdc-wdm: close race between read and workqueue
wdm_read() cannot race with itself. However, in service_outstanding_interrupt() it can race with the workqueue, which can be triggered by error handling. Hence we need to make sure that the WDM_RESPONDING flag is not just only set but tested. Fixes: afba937e540c9 ("USB: CDC WDM driver") Cc: stable <stable@kernel.org> Signed-off-by: Oliver Neukum <oneukum@suse.com> Link: https://lore.kernel.org/r/20240314115132.3907-1-oneukum@suse.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/class')
-rw-r--r--drivers/usb/class/cdc-wdm.c6
1 files changed, 5 insertions, 1 deletions
diff --git a/drivers/usb/class/cdc-wdm.c b/drivers/usb/class/cdc-wdm.c
index c553decb5461..c8262e2f2917 100644
--- a/drivers/usb/class/cdc-wdm.c
+++ b/drivers/usb/class/cdc-wdm.c
@@ -485,6 +485,7 @@ out_free_mem:
static int service_outstanding_interrupt(struct wdm_device *desc)
{
int rv = 0;
+ int used;
/* submit read urb only if the device is waiting for it */
if (!desc->resp_count || !--desc->resp_count)
@@ -499,7 +500,10 @@ static int service_outstanding_interrupt(struct wdm_device *desc)
goto out;
}
- set_bit(WDM_RESPONDING, &desc->flags);
+ used = test_and_set_bit(WDM_RESPONDING, &desc->flags);
+ if (used)
+ goto out;
+
spin_unlock_irq(&desc->iuspin);
rv = usb_submit_urb(desc->response, GFP_KERNEL);
spin_lock_irq(&desc->iuspin);