From: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
To: Eric Dumazet <edumazet@kernel.org>,
"David S . Miller" <davem@davemloft.net>,
Jakub Kicinski <kuba@kernel.org>,
Paolo Abeni <pabeni@redhat.com>
Cc: Simon Horman <horms@kernel.org>,
David Ahern <dsahern@kernel.org>,
Ido Schimmel <idosch@nvidia.com>,
netdev@vger.kernel.org, edumazet@google.com,
Eric Dumazet <edumazet@kernel.org>,
Jiayuan Chen <jiayuan.chen@linux.dev>
Subject: Re: [PATCH v2 net 1/2] ipv4: fix IP ID reuse in ip_select_ident_segs()
Date: Wed, 30 Sep 2026 11:11:55 -0400 [thread overview]
Message-ID: <willemdebruijn.kernel.39a4c29511f@gmail.com> (raw)
In-Reply-To: <20260930144018.1174068-2-edumazet@kernel.org>
Eric Dumazet wrote:
> ip_select_ident_segs() must put the first of the @segs reserved IP IDs
> in iph->id, as GSO assigns id, id + 1, ..., id + segs - 1 to segments.
>
> Commit f866fbc842de ("ipv4: fix data-races around inet->inet_id")
> used atomic_add_return() for non-TCP sockets, which returns the first
> ID of the next packet instead. Consecutive GSO packets can then reuse
> IP IDs.
>
> SCTP GSO is affected. Other callers use segs == 1, and only see
> a harmless off-by-one (UDP GSO has a separate, older issue).
>
> Use atomic_fetch_add() instead, like the TCP path.
>
> Fixes: f866fbc842de ("ipv4: fix data-races around inet->inet_id")
> Signed-off-by: Eric Dumazet <edumazet@kernel.org>
> Reviewed-by: Jiayuan Chen <jiayuan.chen@linux.dev>
> Reviewed-by: David Ahern <dsahern@kernel.org>
Reviewed-by: Willem de Bruijn <willemb@google.com>
next prev parent reply other threads:[~2026-09-30 15:12 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-30 14:40 [PATCH v2 net 0/2] ipv4: fix IP ID reuse for GSO packets Eric Dumazet
2026-09-30 14:40 ` [PATCH v2 net 1/2] ipv4: fix IP ID reuse in ip_select_ident_segs() Eric Dumazet
2026-09-30 15:11 ` Willem de Bruijn [this message]
2026-09-30 14:40 ` [PATCH v2 net 2/2] ipv4: reserve one IP ID per segment for UDP GSO packets Eric Dumazet
2026-09-30 15:12 ` Willem de Bruijn
2026-10-05 22:10 ` [PATCH v2 net 0/2] ipv4: fix IP ID reuse for " patchwork-bot+netdevbpf
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=willemdebruijn.kernel.39a4c29511f@gmail.com \
--to=willemdebruijn.kernel@gmail.com \
--cc=davem@davemloft.net \
--cc=dsahern@kernel.org \
--cc=edumazet@google.com \
--cc=edumazet@kernel.org \
--cc=horms@kernel.org \
--cc=idosch@nvidia.com \
--cc=jiayuan.chen@linux.dev \
--cc=kuba@kernel.org \
--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 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.