From: Qiang.zhang qiang.zhang@windriver.com
commit 30fad76ce4e98263edfa8f885c81d5426c1bf169 upstream.
rcu: INFO: rcu_preempt self-detected stall on CPU rcu: 1-...!: (2 ticks this GP) idle=d92/1/0x4000000000000000 softirq=25390/25392 fqs=3 (t=12164 jiffies g=31645 q=43226) rcu: rcu_preempt kthread starved for 12162 jiffies! g31645 f0x0 RCU_GP_WAIT_FQS(5) ->state=0x0 ->cpu=0 rcu: Unless rcu_preempt kthread gets sufficient CPU time, OOM is now expected behavior. rcu: RCU grace-period kthread stack dump: task:rcu_preempt state:R running task ........... usbtmc 3-1:0.0: unknown status received: -71 usbtmc 3-1:0.0: unknown status received: -71 usbtmc 3-1:0.0: unknown status received: -71 usbtmc 3-1:0.0: unknown status received: -71 usbtmc 3-1:0.0: unknown status received: -71 usbtmc 3-1:0.0: unknown status received: -71 usbtmc 3-1:0.0: unknown status received: -71 usbtmc 3-1:0.0: unknown status received: -71 usbtmc 3-1:0.0: usb_submit_urb failed: -19
The function usbtmc_interrupt() resubmits urbs when the error status of an urb is -EPROTO. In systems using the dummy_hcd usb controller this can result in endless interrupt loops when the usbtmc device is disconnected from the host system.
Since host controller drivers already try to recover from transmission errors, there is no need to resubmit the urb or try other solutions to repair the error situation.
In case of errors the INT pipe just stops to wait for further packets.
Fixes: dbf3e7f654c0 ("Implement an ioctl to support the USMTMC-USB488 READ_STATUS_BYTE operation") Cc: stable@vger.kernel.org Reported-by: syzbot+e2eae5639e7203360018@syzkaller.appspotmail.com Signed-off-by: Qiang.zhang qiang.zhang@windriver.com Acked-by: Guido Kiener guido.kiener@rohde-schwarz.com Link: https://lore.kernel.org/r/20210723004334.458930-1-qiang.zhang@windriver.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/usb/class/usbtmc.c | 9 +-------- 1 file changed, 1 insertion(+), 8 deletions(-)
--- a/drivers/usb/class/usbtmc.c +++ b/drivers/usb/class/usbtmc.c @@ -2283,17 +2283,10 @@ static void usbtmc_interrupt(struct urb dev_err(dev, "overflow with length %d, actual length is %d\n", data->iin_wMaxPacketSize, urb->actual_length); fallthrough; - case -ECONNRESET: - case -ENOENT: - case -ESHUTDOWN: - case -EILSEQ: - case -ETIME: - case -EPIPE: + default: /* urb terminated, clean up */ dev_dbg(dev, "urb terminated, status: %d\n", status); return; - default: - dev_err(dev, "unknown status received: %d\n", status); } exit: rv = usb_submit_urb(urb, GFP_ATOMIC);