From: Jakub Kicinski <kuba@kernel.org>
To: Saurabh Sengar <ssengar@linux.microsoft.com>
Cc: kys@microsoft.com, haiyangz@microsoft.com, wei.liu@kernel.org,
decui@microsoft.com, andrew+netdev@lunn.ch, davem@davemloft.net,
edumazet@google.com, pabeni@redhat.com, horms@kernel.org,
ast@kernel.org, daniel@iogearbox.net, hawk@kernel.org,
john.fastabend@gmail.com, sdf@fomichev.me, kuniyu@amazon.com,
ahmed.zaki@intel.com, aleksander.lobakin@intel.com,
linux-hyperv@vger.kernel.org, netdev@vger.kernel.org,
linux-kernel@vger.kernel.org, bpf@vger.kernel.org,
ssengar@microsoft.com, stable@vger.kernel.org
Subject: Re: [PATCH net,v2] hv_netvsc: fix potential deadlock in netvsc_vf_setxdp()
Date: Thu, 22 May 2025 15:13:46 -0700 [thread overview]
Message-ID: <20250522151346.57390f40@kernel.org> (raw)
In-Reply-To: <1747823103-3420-1-git-send-email-ssengar@linux.microsoft.com>
On Wed, 21 May 2025 03:25:03 -0700 Saurabh Sengar wrote:
> The MANA driver's probe registers netdevice via the following call chain:
>
> mana_probe()
> register_netdev()
> register_netdevice()
>
> register_netdevice() calls notifier callback for netvsc driver,
> holding the netdev mutex via netdev_lock_ops().
>
> Further this netvsc notifier callback end up attempting to acquire the
> same lock again in dev_xdp_propagate() leading to deadlock.
>
> netvsc_netdev_event()
> netvsc_vf_setxdp()
> dev_xdp_propagate()
>
> This deadlock was not observed so far because net_shaper_ops was never set,
The lock is on the VF, I think you meant to say that no device you use
in Azure is ops locked?
There's also the call to netvsc_register_vf() on probe path, please
fix or explain why it doesn't need locking in the commit message.
--
pw-bot: cr
next prev parent reply other threads:[~2025-05-22 22:13 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-05-21 10:25 [PATCH net,v2] hv_netvsc: fix potential deadlock in netvsc_vf_setxdp() Saurabh Sengar
2025-05-21 10:51 ` Subbaraya Sundeep
2025-05-22 22:13 ` Jakub Kicinski [this message]
2025-05-23 4:06 ` Saurabh Singh Sengar
2025-05-23 12:48 ` Saurabh Singh Sengar
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