From: Vladis Dronov <vdronov@redhat.com>
To: Alan Stern <stern@rowland.harvard.edu>
Cc: Andrey Konovalov <andreyknvl@google.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Oliver Neukum <oneukum@suse.com>,
Hans de Goede <hdegoede@redhat.com>,
syzkaller <syzkaller@googlegroups.com>,
USB list <linux-usb@vger.kernel.org>,
LKML <linux-kernel@vger.kernel.org>,
stable <stable@vger.kernel.org>
Subject: Re: [PATCH] usb: usbfs: fix crash in check_ctrlrecip()->usb_find_alt_setting()
Date: Tue, 25 Sep 2018 14:55:13 -0400 (EDT) [thread overview]
Message-ID: <1810191004.16066868.1537901713871.JavaMail.zimbra@redhat.com> (raw)
In-Reply-To: <Pine.LNX.4.44L0.1809251352540.1517-100000@iolanthe.rowland.org>
Hello, Alan, Andrey, all,
> > > (You'll be lucky if Linus doesn't see that. He yells at anybody who
> > > suggests adding BUG_ON for anything that doesn't completely crash
Now, may be not )
> > > How is this different from calling kfree() with a NULL argument?
It is not, it is the same case.
> > What about adding a WARN_ON()? It doesn't crash the kernel and it will
> > be detected and reported by syzbot.
Yes, that would be a great solution.
> Sure, we could do that. But would be the point?
We know when usb_find_alt_setting() callers do smth weird and go fix them.
> After c9a4cb204e9e, calling usb_find_alt_setting() with a NULL config is
> no more of a bug than calling kfree() with a NULL pointer.
Yes, exactly.
> You wouldn't want to put a WARN_ON in kfree(), would you?
Honestly, in the ideal world I would, again, to be aware when some code does
something weird so we know about it. But this world is this world, it needs
more performance to the throne of performance.
I have no other arguments except the above, please, feel free to not to accept
my patch.
Best regards,
Vladis Dronov | Red Hat, Inc. | Product Security Engineer
next prev parent reply other threads:[~2018-09-25 18:55 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-25 12:22 [PATCH] usb: usbfs: fix crash in check_ctrlrecip()->usb_find_alt_setting() Vladis Dronov
2018-09-25 14:14 ` Alan Stern
2018-09-25 14:55 ` Vladis Dronov
2018-09-25 15:15 ` Alan Stern
2018-09-25 15:17 ` Andrey Konovalov
2018-09-25 17:54 ` Alan Stern
2018-09-25 18:55 ` Vladis Dronov [this message]
2018-09-25 20:44 ` Alan Stern
2018-09-26 8:22 ` Vladis Dronov
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