From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
To: Oliver Neukum <oneukum@suse.com>
Cc: "Alan Stern" <stern@rowland.harvard.edu>,
"Greg Kroah-Hartman" <gregkh@linuxfoundation.org>,
"Jakub Kicinski" <kuba@kernel.org>,
"Ömer Mete Kaya" <omermetekaya0@gmail.com>,
netdev@vger.kernel.org, andrew+netdev@lunn.ch,
davem@davemloft.net, edumazet@google.com, pabeni@redhat.com,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
david.laight.linux@gmail.com,
syzbot+04cd90bb99c6ef81a65d@syzkaller.appspotmail.com
Subject: Re: [PATCH net v6] usbnet: fix smp_processor_id() use in preemptible context
Date: Tue, 13 Oct 2026 11:20:42 +0200 [thread overview]
Message-ID: <20261013092042.drwtxbGU@linutronix.de> (raw)
In-Reply-To: <4d3a6c5c-7516-4bab-ac0a-3cf4d7a034a2@suse.com>
On 2026-10-13 10:54:09 [+0200], Oliver Neukum wrote:
> On 12.10.26 22:26, Alan Stern wrote:
> > Today you fix VHCI, tomorrow some other virtual HCD will cause problems.
> >
> > Should we document any requirements that all HCDs will have to follow
> > and that all completion handlers can rely on?
>
> Numerous corner cases. For example I strongly suspect that unloading
> the driver for the HC will always complete URBs synchronously.
> Please do not do this.
Sorry, I have hard time to parse this. The expectation of the USB driver
(was) that the completion handler is invoked in interrupt context.
Therefore BH is disabled one way or another.
Are you saying we should not have this behaviour documented/ expected
and assume preemptible context because "rmmod hcd" will complete all
enqueued URBs in the rmmod context?
> Regards
> Oliver
Sebastian
prev parent reply other threads:[~2026-10-13 9:20 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-04 21:59 [PATCH net v6] usbnet: fix smp_processor_id() use in preemptible context Ömer Mete Kaya
2026-10-08 3:00 ` Jakub Kicinski
2026-10-08 14:16 ` Alan Stern
2026-10-08 16:43 ` Jakub Kicinski
2026-10-08 18:03 ` Alan Stern
2026-10-09 11:31 ` Greg Kroah-Hartman
2026-10-12 19:49 ` Sebastian Andrzej Siewior
2026-10-12 20:26 ` Alan Stern
2026-10-12 21:25 ` Sebastian Andrzej Siewior
2026-10-13 2:09 ` Alan Stern
2026-10-13 9:11 ` Paolo Abeni
2026-10-13 9:22 ` Sebastian Andrzej Siewior
2026-10-13 8:54 ` Oliver Neukum
2026-10-13 9:20 ` Sebastian Andrzej Siewior [this message]
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