From: Johannes Berg <johannes@sipsolutions.net>
To: linux-kernel@vger.kernel.org
Cc: nstange@suse.de, ap420073@gmail.com, David.Laight@aculab.com,
netdev@vger.kernel.org, linux-wireless@vger.kernel.org,
gregkh@linuxfoundation.org, rafael@kernel.org
Subject: Re: [RFC] debugfs: protect against rmmod while files are open
Date: Fri, 09 Oct 2020 12:48:05 +0200 [thread overview]
Message-ID: <2a333c2a50c676c461c1e2da5847dd4024099909.camel@sipsolutions.net> (raw)
In-Reply-To: <20201009124113.a723e46a677a.Ib6576679bb8db01eb34d3dce77c4c6899c28ce26@changeid> (sfid-20201009_124139_179083_C8D99C3A)
On Fri, 2020-10-09 at 12:41 +0200, Johannes Berg wrote:
> If the fops doesn't have a release method, we don't even need
> to keep a reference to the real_fops, we can just fops_put()
> them already in debugfs remove, and a later full_proxy_release()
> won't call anything anyway - this just crashed/UAFed because it
> used real_fops, not because there was actually a (now invalid)
> release() method.
I actually implemented something a bit better than what I described - we
never need a reference to the real_fops for the release method alone,
and that means if the release method is in the kernel image, rather than
a module, it can still be called.
That together should reduce the ~117 places you changed in the large
patchset to around a handful.
johannes
next prev parent reply other threads:[~2020-10-09 10:48 UTC|newest]
Thread overview: 28+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-08 15:48 [PATCH net 000/117] net: avoid to remove module when its debugfs is being used Taehee Yoo
2020-10-08 15:59 ` David Laight
2020-10-08 16:14 ` Johannes Berg
2020-10-08 16:37 ` Taehee Yoo
2020-10-09 5:38 ` Nicolai Stange
2020-10-09 10:07 ` Taehee Yoo
2020-10-09 5:09 ` Nicolai Stange
2020-10-09 7:45 ` Johannes Berg
2020-10-09 10:15 ` Taehee Yoo
2020-10-09 10:21 ` Johannes Berg
2020-10-09 10:41 ` [RFC] debugfs: protect against rmmod while files are open Johannes Berg
2020-10-09 10:48 ` Johannes Berg [this message]
2020-10-09 10:56 ` David Laight
2020-10-09 10:56 ` Johannes Berg
2020-10-09 11:15 ` gregkh
2020-10-09 15:33 ` [PATCH net 000/117] net: avoid to remove module when its debugfs is being used Steve deRosier
2020-10-09 7:53 ` [CRAZY-RFF] debugfs: track open files and release on remove Johannes Berg
2020-10-09 8:03 ` Greg KH
2020-10-09 8:06 ` Johannes Berg
2020-10-09 8:16 ` Greg KH
2020-10-09 8:19 ` Johannes Berg
2020-10-09 8:34 ` David Laight
2020-10-09 8:44 ` Johannes Berg
2020-10-09 9:00 ` David Laight
2020-10-09 8:47 ` Greg KH
2020-10-09 8:48 ` Johannes Berg
2020-10-10 9:38 ` Greg KH
2020-10-10 10:47 ` Johannes Berg
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