From: Slawomir Stepien <sst@poczta.fm>
To: Jakub Kicinski <kuba@kernel.org>
Cc: syzbot <syzbot@kernel.org>,
syzkaller-bugs@googlegroups.com,
Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
netdev@vger.kernel.org, Paolo Abeni <pabeni@redhat.com>,
linux-kernel@vger.kernel.org, syzbot@lists.linux.dev
Subject: Re: [PATCH] netdevsim: fix deadlock in nsim_bus_dev_max_vfs_write()
Date: Fri, 7 Aug 2026 09:31:20 +0200 [thread overview]
Message-ID: <anWJyHCic8XvA0Q2@nr200> (raw)
In-Reply-To: <20260805160851.571ed66f@kernel.org>
On sie 05, 2026 16:08, Jakub Kicinski wrote:
> On Fri, 31 Jul 2026 09:55:04 +0000 (UTC) syzbot wrote:
> > --- a/drivers/net/netdevsim/dev.c
> > +++ b/drivers/net/netdevsim/dev.c
> > @@ -273,7 +273,11 @@ static ssize_t nsim_bus_dev_max_vfs_write(struct file *file,
>
> Sorry to chime in poniewczasie.
> Please delete this file. netdevsim is a harness for in-tree selftests,
> none seems to be reading or writing the debugfs num_vfs AFAICT
> so let's just drop it?
That's true, but is netdevsim used *just* by the selftests (or was designed with only selftests in
mind)? What if someone is using it without selftests?
On the other hand: what sashiko found:
https://netdev-ai.bots.linux.dev/sashiko/#/patchset/b7bf56ea-7522-4163-acd5-aaa69ad03b3a%40mail.kernel.org
is true: the same issue will be with e.g. break_health. So it seems to me that a better approach
would be to change when the debugfs files are removed.
It seems to me that change in nsim_drv_remove() might be easy, but what about
nsim_dev_reload_down()...it seems it will have the same deadlock. Or am I missing something for this
case?
--
Slawomir Stepien
next prev parent reply other threads:[~2026-08-07 7:31 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-07-31 9:55 [PATCH] netdevsim: fix deadlock in nsim_bus_dev_max_vfs_write() syzbot
2026-08-04 14:33 ` Paolo Abeni
2026-08-05 8:55 ` Slawomir Stepien
2026-08-05 9:05 ` Paolo Abeni
2026-08-05 23:08 ` Jakub Kicinski
2026-08-07 7:31 ` Slawomir Stepien [this message]
2026-08-07 21:47 ` Jakub Kicinski
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