From: Mathias Nyman <mathias.nyman@linux.intel.com>
To: Thinh Nguyen <Thinh.Nguyen@synopsys.com>,
Alan Stern <stern@rowland.harvard.edu>,
Mathias Nyman <mathias.nyman@intel.com>
Cc: Guido Kiener <Guido.Kiener@rohde-schwarz.com>,
dave penkler <dpenkler@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>,
syzbot <syzbot+e2eae5639e7203360018@syzkaller.appspotmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
"lee.jones@linaro.org" <lee.jones@linaro.org>,
USB list <linux-usb@vger.kernel.org>,
"bp@alien8.de" <bp@alien8.de>,
"dwmw@amazon.co.uk" <dwmw@amazon.co.uk>,
"hpa@zytor.com" <hpa@zytor.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"luto@kernel.org" <luto@kernel.org>,
"mingo@redhat.com" <mingo@redhat.com>,
"syzkaller-bugs@googlegroups.com"
<syzkaller-bugs@googlegroups.com>,
"tglx@linutronix.de" <tglx@linutronix.de>,
"x86@kernel.org" <x86@kernel.org>
Subject: Re: [syzbot] INFO: rcu detected stall in tx
Date: Mon, 24 May 2021 18:18:59 +0300 [thread overview]
Message-ID: <37c41d87-6e30-1557-7991-0b7bca615be1@linux.intel.com> (raw)
In-Reply-To: <74b2133b-2f77-c86f-4c8b-1189332617d3@synopsys.com>
On 20.5.2021 23.30, Thinh Nguyen wrote:
> +Mathias
>
...
> Hm... looks like we have a couple of issues in the uas storage class
> driver and the xhci driver.
>
> We may need to fix that in the uas storage driver because it doesn't
> seem to handle it. (check uas_data_cmplt() in uas.c).
>
> As for the xhci driver, there maybe a case where the stream URB never
> gets to complete because the transaction err_count is not properly
> updated. The err_count for transaction error is stored in ep_ring, but
> the xhci driver may not be able to lookup the correct ep_ring based on
> TRB address for streams. There are cases for streams where the event
> TRBs have their TRB pointer field cleared to '0' (xhci spec section
> 4.12.2). If the xhci driver doesn't see ep_ring for transaction error,
> it automatically does a soft-retry. This is seen from one of our
> testings that the driver was repeatedly doing soft-retry until the class
> driver timed out.
>
> Hi Mathias, maybe you have some comment on this? Thanks.
This is true, if TRB pointer is 0 then there is no retry limit for soft retry.
We should add one and prevent a loop. after e few soft resets we can end with a
hard reset to clear the host side endpoint halt.
We don't know the URB that was being tansferred during the error, and can't
give it back with a proper error code.
In that sense we still end up waiting for a timeout and someone to cancel
the urb.
-Mathias
next prev parent reply other threads:[~2021-05-24 15:21 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-05-19 16:14 Re: Re: Re: Re: Re: [syzbot] INFO: rcu detected stall in tx Guido Kiener
2021-05-19 17:35 ` Alan Stern
2021-05-19 19:38 ` Thinh Nguyen
2021-05-20 2:01 ` Alan Stern
2021-05-20 20:30 ` Thinh Nguyen
2021-05-20 21:05 ` Recovering from transaction errors [was: Re: [syzbot] INFO: rcu detected stall in tx] Alan Stern
2021-05-20 21:23 ` Thinh Nguyen
2021-05-21 1:21 ` Alan Stern
2021-05-21 2:12 ` Thinh Nguyen
2021-05-21 14:34 ` Alan Stern
2021-05-21 20:00 ` Thinh Nguyen
2021-05-24 15:18 ` Mathias Nyman [this message]
2021-05-24 18:55 ` [syzbot] INFO: rcu detected stall in tx Alan Stern
2021-05-24 19:23 ` Thinh Nguyen
2021-05-24 22:16 ` Mathias Nyman
2021-05-24 22:48 ` Thinh Nguyen
2021-05-19 18:04 ` Re: Re: Re: Re: " Lee Jones
2021-05-20 21:25 Guido Kiener
2021-05-21 1:24 ` Alan Stern
2021-05-21 22:17 ` guido
2021-05-22 2:13 ` Alan Stern
[not found] <000000000000a9b79905c04e25a0@google.com>
2021-04-19 7:27 ` Dmitry Vyukov
2021-06-28 6:38 ` Zhang, Qiang
2021-06-28 14:17 ` Alan Stern
2021-06-27 20:20 ` syzbot
2021-09-04 7:55 ` syzbot
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