From: Jakub Kicinski <kuba@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: syzbot <syzbot+039399a9b96297ddedca@syzkaller.appspotmail.com>,
linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com,
netdev@vger.kernel.org, Paolo Abeni <pabeni@redhat.com>,
"David S. Miller" <davem@davemloft.net>
Subject: Re: [syzbot] [kernel?] BUG: unable to handle kernel NULL pointer dereference in hrtimer_active
Date: Wed, 21 Feb 2024 13:29:16 -0800 [thread overview]
Message-ID: <20240221132916.6c7c4219@kernel.org> (raw)
In-Reply-To: <875xytjnio.ffs@tglx>
On Tue, 13 Feb 2024 00:01:03 +0100 Thomas Gleixner wrote:
> So something in that syzbot test case manages to tear down a napi
> context which has not yet been fully initialized. While the rest of
> napi_disable() does not care much as long as neither NAPIF_STATE_SCHED
> nor NAPIF_STATE_NPSVC are set in napi->state, hrtimer_cancel() pretty
> much cares as demonstrated by the NULL pointer dereference.
>
> While it would be trivial to harden the hrtimer code for the case that a
> non-initialized hrtimer is canceled, I wonder whether this invocation of
> napi_disable() is harmless (aside of the hrtimer issue) or if there are
> some hidden subtle issues with that.
Thanks for the forward, I stared at it for a bit and I can see one way
to make veth disable unregistered NAPI. I'll send a fix shortly.
prev parent reply other threads:[~2024-02-21 21:29 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <00000000000014671906112cb2ef@google.com>
2024-02-12 23:01 ` [syzbot] [kernel?] BUG: unable to handle kernel NULL pointer dereference in hrtimer_active Thomas Gleixner
2024-02-21 21:29 ` Jakub Kicinski [this message]
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