From: Jakub Kicinski <kuba@kernel.org>
To: Alexander H Duyck <alexander.duyck@gmail.com>
Cc: Liang Chen <liangchen.linux@gmail.com>,
ilias.apalodimas@linaro.org, hawk@kernel.org,
davem@davemloft.net, edumazet@google.com, pabeni@redhat.com,
netdev@vger.kernel.org
Subject: Re: [PATCH] skbuff: Fix a race between coalescing and releasing SKBs
Date: Tue, 4 Apr 2023 18:21:16 -0700 [thread overview]
Message-ID: <20230404182116.5795563c@kernel.org> (raw)
In-Reply-To: <7331d6d3f9044e386e425e89b1fc32d60b046cf3.camel@gmail.com>
On Tue, 04 Apr 2023 08:51:18 -0700 Alexander H Duyck wrote:
> I'm not quite sure I agree with the fix. Couldn't we just modify the
> check further down that does:
>
> if (!skb_cloned(from))
> from_shinfo->nr_frags = 0;
>
> And instead just make that:
> if (!skb->cloned || (!skb_cloned(from) && !from->pp_recycle))
> from_shinfo->nr_frags = 0;
>
> With that we would retain the existing behavior and in the case of
> cloned from frames we would take the references and let the original
> from skb freed to take care of pulling the pages from the page pool.
Sounds like a better fix, indeed. But this sort of code will require
another fat comment above to explain why. This:
if (to->pp_recycle == from->pp_recycle && !skb_cloned(from))
is much easier to understand, no?
We should at least include that in the explanatory comment, I reckon...
next prev parent reply other threads:[~2023-04-05 1:21 UTC|newest]
Thread overview: 17+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-04 7:47 [PATCH] skbuff: Fix a race between coalescing and releasing SKBs Liang Chen
2023-04-04 11:18 ` Yunsheng Lin
2023-04-04 15:51 ` Alexander H Duyck
2023-04-05 1:21 ` Jakub Kicinski [this message]
2023-04-05 8:18 ` Liang Chen
2023-04-05 14:50 ` Jakub Kicinski
2023-04-06 3:22 ` Liang Chen
2023-04-05 15:06 ` Alexander Duyck
2023-04-06 3:28 ` Liang Chen
2023-04-06 9:56 ` Eric Dumazet
2023-04-06 10:46 ` Ilias Apalodimas
2023-04-06 11:54 ` Liang Chen
2023-04-06 14:59 ` Jakub Kicinski
2023-04-07 0:45 ` Liang Chen
2023-04-11 0:26 ` Jakub Kicinski
2023-04-12 7:27 ` Liang Chen
2023-04-12 13:58 ` Jakub Kicinski
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20230404182116.5795563c@kernel.org \
--to=kuba@kernel.org \
--cc=alexander.duyck@gmail.com \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=hawk@kernel.org \
--cc=ilias.apalodimas@linaro.org \
--cc=liangchen.linux@gmail.com \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).