From: Greg KH <gregkh@linuxfoundation.org>
To: Your Real Name <zhutong@amazon.com>
Cc: David Miller <davem@davemloft.net>,
sashal@kernel.org, edumazet@google.com, vvs@virtuozzo.com,
netdev@vger.kernel.org, stable@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH] neighbour: Disregard DEAD dst in neigh_update
Date: Fri, 8 Jan 2021 08:34:16 +0100 [thread overview]
Message-ID: <X/gK+KBlROogPCol@kroah.com> (raw)
In-Reply-To: <20210108023637.GA31904@ucf43ac461c9a53.ant.amazon.com>
On Thu, Jan 07, 2021 at 09:36:37PM -0500, Your Real Name wrote:
> On Tue, Jan 05, 2021 at 04:05:21PM -0800, David Miller wrote:
> >
> >
> > From: Tong Zhu <zhutong@amazon.com>
> > Date: Wed, 30 Dec 2020 17:54:23 -0500
> >
> > > In 4.x kernel a dst in DST_OBSOLETE_DEAD state is associated
> > > with loopback net_device and leads to loopback neighbour. It
> > > leads to an ethernet header with all zero addresses.
> > >
> > > A very troubling case is working with mac80211 and ath9k.
> > > A packet with all zero source MAC address to mac80211 will
> > > eventually fail ieee80211_find_sta_by_ifaddr in ath9k (xmit.c).
> > > As result, ath9k flushes tx queue (ath_tx_complete_aggr) without
> > > updating baw (block ack window), damages baw logic and disables
> > > transmission.
> > >
> > > Signed-off-by: Tong Zhu <zhutong@amazon.com>
> >
> > Please repost with an appropriate Fixes: tag.
> >
> > Thanks.
>
> I had a second thought on this. This fix should go mainline too. This is a
> case we are sending out queued packets when arp reply from the neighbour
> comes in. With 5.x kernel, a dst in DST_OBSOLETE_DEAD state leads to dropping
> of this packet. It is not as bad as with 4.x kernel that may end up with an
> all-zero mac address packet out to ethernet or choking up ath9k when using
> block ack. Dropping the packet is still wrong. I’ll repost as a fix to
> mainline and target backport to 4.x LTS releases.
That's how kernel development works, please read
https://www.kernel.org/doc/html/latest/process/stable-kernel-rules.html
for how stable kernels are allowed to accept patches.
good luck!
greg k-h
next prev parent reply other threads:[~2021-01-08 7:35 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-30 22:54 [PATCH] neighbour: Disregard DEAD dst in neigh_update Tong Zhu
2021-01-06 0:05 ` David Miller
2021-01-08 2:36 ` Your Real Name
2021-01-08 7:34 ` Greg KH [this message]
-- strict thread matches above, loose matches on Subject: below --
2021-03-19 18:33 Tong Zhu
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=X/gK+KBlROogPCol@kroah.com \
--to=gregkh@linuxfoundation.org \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=linux-kernel@vger.kernel.org \
--cc=netdev@vger.kernel.org \
--cc=sashal@kernel.org \
--cc=stable@vger.kernel.org \
--cc=vvs@virtuozzo.com \
--cc=zhutong@amazon.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.