From: David Laight <david.laight.linux@gmail.com>
To: Josef Bacik <josef@toxicpanda.com>
Cc: Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@kernel.org>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Simon Horman <horms@kernel.org>, David Ahern <dsahern@kernel.org>,
Ido Schimmel <idosch@nvidia.com>,
Trond Myklebust <trondmy@kernel.org>,
Anna Schumaker <anna@kernel.org>, Chuck Lever <cel@kernel.org>,
Jeff Layton <jlayton@kernel.org>, NeilBrown <neil@brown.name>,
Olga Kornievskaia <okorniev@redhat.com>,
Dai Ngo <Dai.Ngo@oracle.com>, Tom Talpey <tom@talpey.com>,
Mina Almasry <almasrymina@google.com>,
Kaiyuan Zhang <kaiyuanz@google.com>,
Willem de Bruijn <willemb@google.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-nfs@vger.kernel.org, stable@vger.kernel.org
Subject: Re: [PATCH net v2] net: skbuff: make skb_copy_and_csum_bits() report unreadable frags
Date: Wed, 14 Oct 2026 13:51:54 +0100 [thread overview]
Message-ID: <20261014135154.05de968e@pumpkin> (raw)
In-Reply-To: <20261013-b4-skb-segment-nosg-unreadable-v2-1-6c28d8ffa51e@toxicpanda.com>
On Tue, 13 Oct 2026 18:02:44 +0000
Josef Bacik <josef@toxicpanda.com> wrote:
> Subject: [PATCH net v2] net: skbuff: make skb_copy_and_csum_bits() report unreadable frags
> Date: Tue, 13 Oct 2026 18:02:44 +0000
>
> skb_copy_and_csum_bits() has no way to fail. When it reaches
> unreadable frags it zero-fills the rest of the buffer and returns 0,
> and since commit ab9414ed70bd ("net: skbuff: don't leave stale bytes in
> skb_copy_and_csum_bits()") that 0 is the correct checksum for what's in
> the buffer. Its callers can't tell the copy didn't happen.
Can't you use that fact that the csum function should only return
either 0 or ~0 and use the other value to indicate an error.
ISTR this coming up before with the 'copy_to/from_user_and_csum' code.
David
next prev parent reply other threads:[~2026-10-14 12:51 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-10-13 18:02 [PATCH net v2] net: skbuff: make skb_copy_and_csum_bits() report unreadable frags Josef Bacik
2026-10-13 18:05 ` netdev-bot+sinfo
2026-10-14 14:04 ` Josef Bacik
2026-10-14 12:51 ` David Laight [this message]
2026-10-14 14:04 ` Josef Bacik
2026-10-14 16:30 ` David Laight
2026-10-14 16:52 ` Josef Bacik
2026-10-14 17:27 ` Josef Bacik
2026-10-14 18:17 ` Josef Bacik
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=20261014135154.05de968e@pumpkin \
--to=david.laight.linux@gmail.com \
--cc=Dai.Ngo@oracle.com \
--cc=almasrymina@google.com \
--cc=andrew+netdev@lunn.ch \
--cc=anna@kernel.org \
--cc=cel@kernel.org \
--cc=davem@davemloft.net \
--cc=dsahern@kernel.org \
--cc=edumazet@kernel.org \
--cc=horms@kernel.org \
--cc=idosch@nvidia.com \
--cc=jlayton@kernel.org \
--cc=josef@toxicpanda.com \
--cc=kaiyuanz@google.com \
--cc=kuba@kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-nfs@vger.kernel.org \
--cc=neil@brown.name \
--cc=netdev@vger.kernel.org \
--cc=okorniev@redhat.com \
--cc=pabeni@redhat.com \
--cc=stable@vger.kernel.org \
--cc=tom@talpey.com \
--cc=trondmy@kernel.org \
--cc=willemb@google.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 an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.