From: Alan Stern <stern@rowland.harvard.edu>
To: Anirudh Rayabharam <mail@anirudhrb.com>
Cc: Dmitry Vyukov <dvyukov@google.com>,
syzbot <syzbot+eb4674092e6cc8d9e0bd@syzkaller.appspotmail.com>,
Andrey Konovalov <andreyknvl@gmail.com>,
Felipe Balbi <balbi@kernel.org>,
Dan Carpenter <dan.carpenter@oracle.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
LKML <linux-kernel@vger.kernel.org>,
USB list <linux-usb@vger.kernel.org>,
syzkaller-bugs <syzkaller-bugs@googlegroups.com>
Subject: Re: [syzbot] general protection fault in gadget_setup
Date: Fri, 16 Apr 2021 13:46:04 -0400 [thread overview]
Message-ID: <20210416174604.GA47856@rowland.harvard.edu> (raw)
In-Reply-To: <YHnD0AVXiwdsw46L@anirudhrb.com>
On Fri, Apr 16, 2021 at 10:35:20PM +0530, Anirudh Rayabharam wrote:
> On Fri, Apr 16, 2021 at 11:27:34AM -0400, Alan Stern wrote:
> > Actually, I wanted to move this emulation code into a new subroutine and
> > then call that subroutine from _both_ places. Would you like to write
>
> Does it really need to be called from both places?
You know, I was going to say Yes, but now I think you're right; it's not
needed in dummy_udc_stop. This is because core.c always calls
usb_gadget_disconnect before usb_gadget_udc_stop. And we can rely on
this behavior; it's obviously necessary to disconnect from the host
before stopping the UDC driver.
On the other hand, while checking that fact I noticed that
soft_connect_store in core.c doesn't call synchronize_irq in between the
other two, the way usb_gadget_remove_driver does. That seems like a bug
-- if it's necessary to synchronize with the IRQ handler on one path, it
should be necessary on the other path as well. But that's a matter for
a separate patch.
Alan Stern
> > and submit a patch that does this?
>
> Sure! I will do that.
>
> Thanks!
>
> - Anirudh.
prev parent reply other threads:[~2021-04-16 17:46 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-13 8:08 [syzbot] general protection fault in gadget_setup syzbot
2021-04-13 8:12 ` Dmitry Vyukov
2021-04-13 16:13 ` Alan Stern
2021-04-13 16:47 ` Dmitry Vyukov
2021-04-13 16:57 ` Alan Stern
2021-04-13 17:11 ` Dmitry Vyukov
2021-04-15 20:59 ` Alan Stern
2021-04-16 7:21 ` Dmitry Vyukov
2021-04-16 15:29 ` Alan Stern
2021-04-16 5:40 ` Anirudh Rayabharam
2021-04-16 15:27 ` Alan Stern
2021-04-16 17:05 ` Anirudh Rayabharam
2021-04-16 17:46 ` Alan Stern [this message]
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