From: Jens Axboe <[email protected]>
To: Pavel Begunkov <[email protected]>, [email protected]
Cc: Matthew Wilcox <[email protected]>,
yangerkun <[email protected]>,
Stefan Metzmacher <[email protected]>
Subject: Re: [PATCH 5.12] io_uring: Convert personality_idr to XArray
Date: Tue, 9 Mar 2021 13:53:45 -0700 [thread overview]
Message-ID: <[email protected]> (raw)
In-Reply-To: <7ccff36e1375f2b0ebf73d957f037b43becc0dde.1615212806.git.asml.silence@gmail.com>
On 3/8/21 7:16 AM, Pavel Begunkov wrote:
> From: "Matthew Wilcox (Oracle)" <[email protected]>
>
> You can't call idr_remove() from within a idr_for_each() callback,
> but you can call xa_erase() from an xa_for_each() loop, so switch the
> entire personality_idr from the IDR to the XArray. This manifests as a
> use-after-free as idr_for_each() attempts to walk the rest of the node
> after removing the last entry from it.
I applied this one yesterday, just forgot to reply here. I agree with
Matthew's optimization, though I suspect we'll have a few creds at
most and it won't make much of a difference in real life. Buffers would
likely be a lot more plentiful, so it's worth keeping in mind for
that one.
--
Jens Axboe
prev parent reply other threads:[~2021-03-09 20:54 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-03-08 14:16 [PATCH 5.12] io_uring: Convert personality_idr to XArray Pavel Begunkov
2021-03-08 14:22 ` Pavel Begunkov
2021-03-08 16:16 ` Matthew Wilcox
2021-03-09 11:23 ` yangerkun
2021-03-13 8:02 ` yangerkun
2021-03-13 15:34 ` Jens Axboe
2021-03-13 19:01 ` Jens Axboe
2021-03-13 19:30 ` Jens Axboe
2021-03-13 19:54 ` Matthew Wilcox
2021-03-13 20:13 ` Jens Axboe
2021-03-13 20:22 ` Jens Axboe
2021-03-09 20:53 ` Jens Axboe [this message]
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