From: Lee Jones <lee.jones@linaro.org>
To: Guido Kiener <Guido.Kiener@rohde-schwarz.com>
Cc: Alan Stern <stern@rowland.harvard.edu>,
dave penkler <dpenkler@gmail.com>,
Dmitry Vyukov <dvyukov@google.com>,
syzbot <syzbot+e2eae5639e7203360018@syzkaller.appspotmail.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.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: Re: Re: Re: Re: Re: [syzbot] INFO: rcu detected stall in tx
Date: Wed, 19 May 2021 19:04:14 +0100 [thread overview]
Message-ID: <20210519180414.GL2549456@dell> (raw)
In-Reply-To: <d673611ca53f42a3a629eb051cabc6eb@rohde-schwarz.com>
On Wed, 19 May 2021, Guido Kiener wrote:
> > On Wed, May 19, 2021 at 10:48:29AM +0200, dave penkler wrote:
> > > On Sat, 8 May 2021 at 16:29, Alan Stern <stern@rowland.harvard.edu> wrote:
> > > >
> > > > On Sat, May 08, 2021 at 10:14:41AM +0200, dave penkler wrote:
> > > > > When the host driver detects a protocol error while processing an
> > > > > URB it completes the URB with EPROTO status and marks the endpoint
> > > > > as halted.
> > > >
> > > > Not true. It does not mark the endpoint as halted, not unless it
> > > > receives a STALL handshake from the device. A STALL is not a
> > > > protocol error.
> > > >
> > > > > When the class driver resubmits the URB and the if the host driver
> > > > > finds the endpoint still marked as halted it should return EPIPE
> > > > > status on the resubmitted URB
> > > >
> > > > Irrelevant.
> > > Not at all. The point is that when an application is talking to an
> > > instrument over the usbtmc driver, the underlying host controller and
> > > its driver will detect and silence a babbling endpoint.
> >
> > No, they won't. That is, they will detect a babble error and return an error status, but
> > they won't silence the endpoint. What makes you think they will?
>
> Maybe there is a misunderstanding. I guess that Dave wanted to propose:
> "EPROTO is a link level issue and needs to be handled by the host driver.
> When the host driver detects a protocol error while processing an
> URB it SHOULD complete the URB with EPROTO status and SHOULD mark the endpoint
> as halted."
> Is this a realistic fix for all host drivers?
>
> -Guido
Guido, would you mind taking a look at your mailer settings please? I
now have >=7 threads running through my inbox with the same subject.
For some reason your mailer is insisting on creating a new one for
each of your replies.
It's also adding odd "re: re: re: ..." prefixes.
TIA
--
Lee Jones [李琼斯]
Senior Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
Follow Linaro: Facebook | Twitter | Blog
prev parent reply other threads:[~2021-05-19 18:04 UTC|newest]
Thread overview: 11+ 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
2021-05-24 15:18 ` Mathias Nyman
2021-05-24 18:55 ` 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 ` Lee Jones [this message]
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