From: Jakub Kicinski <kuba@kernel.org>
To: Rosen Penev <rosenp@gmail.com>
Cc: Jacob Keller <jacob.e.keller@intel.com>,
netdev@vger.kernel.org, Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Paolo Abeni <pabeni@redhat.com>, Jeff Garzik <jeff@garzik.org>,
Roland Dreier <rdreier@cisco.com>,
open list <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH net] net: ibm: emac: mal: fix potential system hang in mal_remove()
Date: Mon, 8 Jun 2026 17:36:38 -0700 [thread overview]
Message-ID: <20260608173638.74da73fe@kernel.org> (raw)
In-Reply-To: <CAKxU2N8oh03r2-zJhbOXF0Qqx7RzNSX=zq+i6Ld1c9YXJqDfKQ@mail.gmail.com>
On Thu, 4 Jun 2026 16:03:43 -0700 Rosen Penev wrote:
> > > - if (!list_empty(&mal->list))
> > > + if (!list_empty(&mal->list)) {
> > > + napi_disable(&mal->napi);
> > > /* This is *very* bad */
> > > WARN(1, KERN_EMERG
> > > "mal%d: commac list is not empty on remove!\n",
> > > mal->index);
> >
> > This one doesn't make sense to me. The list_empty check does a WARN()
> > indicating that this is not supposed to happen.
> >
> > This implies that list_empty should be true, otherwise we'd see a WARN
> > every time mal_remove is called.
> >
> > But in that case, we'd have been calling napi_disable incorrectly in
> > most cases where it was previously unsafe according to your claim.
> >
> > At best, this list_empty check is the wrong way to tell if the napi is
> > disabled, at worst, this whole change is pointless.
> I asked the AI. It doesn't agree:
FTR I agree with Jake, the patch seems to indicate bigger structural
issues. Then again I don't want to encourage the stream of patches
to this driver so let me just apply this..
next prev parent reply other threads:[~2026-06-09 0:36 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-06-03 23:08 [PATCH net] net: ibm: emac: mal: fix potential system hang in mal_remove() Rosen Penev
2026-06-04 18:52 ` Jacob Keller
2026-06-04 23:03 ` Rosen Penev
2026-06-09 0:36 ` Jakub Kicinski [this message]
2026-06-09 1:13 ` Jacob Keller
2026-06-09 1:13 ` Jacob Keller
2026-06-09 1:51 ` Rosen Penev
2026-06-09 0:40 ` patchwork-bot+netdevbpf
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