From: Simon Horman <horms@kernel.org>
To: Jakub Kicinski <kuba@kernel.org>
Cc: davem@davemloft.net, netdev@vger.kernel.org, edumazet@google.com,
pabeni@redhat.com, andrew+netdev@lunn.ch, stable@vger.kernel.org,
syzbot+a78926bdac2adb52dc0e@syzkaller.appspotmail.com,
axboe@kernel.dk, io-uring@vger.kernel.org,
asml.silence@gmail.com
Subject: Re: [PATCH net] net: expect instance lock in netdev_queue_get_dma_dev()
Date: Mon, 10 Aug 2026 11:23:28 +0100 [thread overview]
Message-ID: <20260810102328.GR51943@horms.kernel.org> (raw)
In-Reply-To: <20260806225627.3998672-1-kuba@kernel.org>
On Thu, Aug 06, 2026 at 03:56:26PM -0700, Jakub Kicinski wrote:
> netdev_queue_get_dma_dev() uses "compat" locking assert which wants
> either the rtnl_lock or netdev instance lock. This is not right,
> the callers are taking the instance lock unconditionally. All entry
> points for queue config are purely instance locked.
>
> In other words the callers use netdev_get_by_index_lock(), not
> netdev_get_by_index_lock_ops_compat(). All the state we will
> access is effectively instance lock protected (it's const for
> devices which are not ops-locked).
>
> Update the assert to avoid false positive warnings.
>
> Cc: stable@vger.kernel.org
> Fixes: b6c5f9454ef34 ("io_uring/zcrx: call netdev_queue_get_dma_dev() under instance lock")
> Reported-by: syzbot+a78926bdac2adb52dc0e@syzkaller.appspotmail.com
> Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Reviewed-by: Simon Horman <horms@kernel.org>
next prev parent reply other threads:[~2026-08-10 10:23 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-08-06 22:56 [PATCH net] net: expect instance lock in netdev_queue_get_dma_dev() Jakub Kicinski
2026-08-10 10:23 ` Simon Horman [this message]
2026-08-10 10:27 ` Daniel Borkmann
2026-08-10 23:20 ` 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=20260810102328.GR51943@horms.kernel.org \
--to=horms@kernel.org \
--cc=andrew+netdev@lunn.ch \
--cc=asml.silence@gmail.com \
--cc=axboe@kernel.dk \
--cc=davem@davemloft.net \
--cc=edumazet@google.com \
--cc=io-uring@vger.kernel.org \
--cc=kuba@kernel.org \
--cc=netdev@vger.kernel.org \
--cc=pabeni@redhat.com \
--cc=stable@vger.kernel.org \
--cc=syzbot+a78926bdac2adb52dc0e@syzkaller.appspotmail.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.