From: Alan Stern <stern@rowland.harvard.edu>
To: Pete Zaitcev <zaitcev@redhat.com>
Cc: syzbot <syzbot+56f9673bb4cdcbeb0e92@syzkaller.appspotmail.com>,
<arnd@arndb.de>, <gregkh@linuxfoundation.org>,
<jrdr.linux@gmail.com>, <keescook@chromium.org>,
<kstewart@linuxfoundation.org>,
Kernel development list <linux-kernel@vger.kernel.org>,
USB list <linux-usb@vger.kernel.org>,
<syzkaller-bugs@googlegroups.com>, <tglx@linutronix.de>,
<viro@zeniv.linux.org.uk>
Subject: Re: possible deadlock in mon_bin_vma_fault
Date: Thu, 21 Nov 2019 11:20:20 -0500 (EST) [thread overview]
Message-ID: <Pine.LNX.4.44L0.1911211118450.1553-100000@iolanthe.rowland.org> (raw)
In-Reply-To: <20191121084842.095edf87@suzdal.zaitcev.lan>
On Thu, 21 Nov 2019, Pete Zaitcev wrote:
> Anyway... If you are looking at it too, what do you think about not using
> any locks in mon_bin_vma_fault() at all? Isn't it valid? I think I tried
> to be "safe", but it only uses things that are constants unless we're
> opening and closing; a process cannot make page faults unless it has
> some thing mapped; and that is only possible if device is open and stays
> open. Can you find a hole in this reasoning?
I think you're right. But one thing concerns me: What happens if the
same buffer is mapped by more than one process? Do you allow that? I
haven't read the code in enough detail to see.
Alan Stern
next prev parent reply other threads:[~2019-11-21 16:20 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-03 22:01 possible deadlock in mon_bin_vma_fault syzbot
2019-11-20 12:01 ` syzbot
2019-11-20 16:14 ` Alan Stern
2019-11-20 17:12 ` Pete Zaitcev
2019-11-20 18:47 ` Alan Stern
2019-11-21 14:48 ` Pete Zaitcev
2019-11-21 16:20 ` Alan Stern [this message]
2019-11-21 16:46 ` Pete Zaitcev
2019-11-21 23:38 ` Pete Zaitcev
2019-11-22 7:18 ` Dmitry Vyukov
2019-11-22 15:27 ` Alan Stern
2019-11-22 20:52 ` Pete Zaitcev
2019-11-22 22:13 ` Alan Stern
2019-11-22 22:13 ` syzbot
2019-11-23 17:18 ` Alan Stern
2019-11-23 17:18 ` syzbot
2019-11-24 15:59 ` Alan Stern
2019-11-24 19:10 ` syzbot
2019-11-24 20:55 ` Alan Stern
2019-11-24 23:24 ` syzbot
2019-11-25 0:10 ` Pete Zaitcev
2019-11-25 2:12 ` Alan Stern
2019-11-23 17:18 ` Re: " syzbot
2019-11-22 22:13 ` syzbot
2019-11-20 17:33 ` Pete Zaitcev
2019-11-20 18:18 ` Alan Stern
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