On Fri, Mar 15, 2024 at 09:30:19AM +0800, yuan linyu wrote: > It is possible trigger below warning message from mass storage function, > > WARNING: CPU: 6 PID: 3839 at drivers/usb/gadget/udc/core.c:294 usb_ep_queue+0x7c/0x104 > CPU: 6 PID: 3839 Comm: file-storage Tainted: G S WC O 6.1.25-android14-11-g354e2a7e7cd9 #1 > pstate: 22400005 (nzCv daif +PAN -UAO +TCO -DIT -SSBS BTYPE=--) > pc : usb_ep_queue+0x7c/0x104 > lr : fsg_main_thread+0x494/0x1b3c > > Root cause is mass storage function try to queue request from main thread, > but other thread may already disable ep when function disable. > > As there is no function failure in the driver, in order to avoid effort > to fix warning, change WARN_ON_ONCE() in usb_ep_queue() to pr_debug(). > > Suggested-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> > Cc: <stable@xxxxxxxxxxxxxxx> > Signed-off-by: yuan linyu <yuanlinyu@xxxxxxxxxxx> > --- > v2: change WARN_ON_ONCE() in usb_ep_queue() to pr_debug() > v1: https://lore.kernel.org/linux-usb/20240314065949.2627778-1-yuanlinyu@xxxxxxxxxxx/ > > drivers/usb/gadget/udc/core.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/drivers/usb/gadget/udc/core.c b/drivers/usb/gadget/udc/core.c > index 9d4150124fdb..2fbe5977c11d 100644 > --- a/drivers/usb/gadget/udc/core.c > +++ b/drivers/usb/gadget/udc/core.c > @@ -292,7 +292,8 @@ int usb_ep_queue(struct usb_ep *ep, > { > int ret = 0; > > - if (WARN_ON_ONCE(!ep->enabled && ep->address)) { > + if (!ep->enabled && ep->address) { > + pr_debug("queue disabled ep %x\n", ep->address); > ret = -ESHUTDOWN; > goto out; > } Okay, this a lot better and a much simpler solution to the problem. However, I think the message should be more clear. Something like this: pr_debug("USB gadget: request queued to disabled ep 0x%x (%s)\n", ep->address, ep->name); It's too bad that there isn't enough information available to print the names of the gadget and the function driver. Luckily, most systems will only have one gadget active at a time. Alan Stern
