From: "Tantilov, Emil S" <emil.s.tantilov@intel.com>
To: Jakub Kicinski <kuba@kernel.org>
Cc: Jacob Keller <jacob.e.keller@intel.com>,
Przemek Kitszel <przemyslaw.kitszel@intel.com>,
Andrew Lunn <andrew+netdev@lunn.ch>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
"Paolo Abeni" <pabeni@redhat.com>,
Pavan Kumar Linga <pavan.kumar.linga@intel.com>,
Alexander Lobakin <aleksander.lobakin@intel.com>,
Willem de Bruijn <willemb@google.com>,
Sridhar Samudrala <sridhar.samudrala@intel.com>,
"Phani Burra" <phani.r.burra@intel.com>,
Piotr Kwapulinski <piotr.kwapulinski@intel.com>,
Simon Horman <horms@kernel.org>,
Radoslaw Tyl <radoslawx.tyl@intel.com>,
Jedrzej Jagielski <jedrzej.jagielski@intel.com>,
Mateusz Polchlopek <mateusz.polchlopek@intel.com>,
Anton Nadezhdin <anton.nadezhdin@intel.com>,
Konstantin Ilichev <konstantin.ilichev@intel.com>,
Milena Olech <milena.olech@intel.com>, <netdev@vger.kernel.org>,
<linux-kernel@vger.kernel.org>,
Joshua Hay <joshua.a.hay@intel.com>,
Aleksandr Loktionov <aleksandr.loktionov@intel.com>,
Chittim Madhu <madhu.chittim@intel.com>,
Samuel Salin <Samuel.salin@intel.com>
Subject: Re: [PATCH net 3/8] idpf: fix possible race in idpf_vport_stop()
Date: Mon, 6 Oct 2025 17:07:26 -0700 [thread overview]
Message-ID: <048833d9-01f5-438d-a3fa-354a008ebbd3@intel.com> (raw)
In-Reply-To: <20251006102659.595825fe@kernel.org>
On 10/6/2025 10:26 AM, Jakub Kicinski wrote:
> On Mon, 6 Oct 2025 07:49:32 -0700 Tantilov, Emil S wrote:
>>> Argh, please stop using the flag based state machines. They CANNOT
>>> replace locking. If there was proper locking in place it wouldn't
>>> have mattered when we clear the flag.
>>
>> This patch is resolving a bug in the current logic of how the flag is
>> used (not being atomic and not being cleared properly). I don't think
>> there is an existing lock in place to address this issue, though we are
>> looking to refactor the code over time to remove and/or limit how these
>> flags are used.
>
> Can you share more details about the race? If there is no lock in place
> there's always the risk that:
>
> CPU 0 CPU 1
> idpf_vport_stop() whatever()
> if (test_bit(UP))
> # sees true
> # !< long IRQ arrives
> test_and_clear(UP)
> ...
> all the rest
> ...
> # > long IRQ ends
> proceed but UP isn't really set any more
>
The specific case I was targeting with this patch is for when both
idpf_vport_stop() and idpf_addr_unsync(), called via set_rx_mode attempt
to delete the MAC filters. At least in my testing I have not seen a case
where the set_rx_mode callback will happen before idpf_vport_stop(). I
am assuming due to userspace reacting to the removal of the netdevs.
rmmod-6089 [021] ..... 3521.291596: idpf_remove
<-pci_device_remove
rmmod-6089 [021] ..... 3521.292686: idpf_vport_stop
<-idpf_vport_dealloc
systemd-resolve-1633 [022] b..1. 3521.295320: idpf_set_rx_mode
<-dev_mc_del
systemd-resolve-1633 [022] b..1. 3521.295338: idpf_addr_unsync
<-__hw_addr_sync_dev
systemd-resolve-1633 [022] b..1. 3521.295339: idpf_del_mac_filter
<-idpf_addr_unsync
systemd-resolve-1633 [022] b..1. 3521.295450: idpf_set_rx_mode
<-dev_mc_del
systemd-resolve-1633 [022] b..1. 3521.295451: idpf_addr_unsync
<-__hw_addr_sync_dev
systemd-resolve-1633 [022] b..1. 3521.295451: idpf_del_mac_filter
<-idpf_addr_unsync
rmmod-6089 [002] ..... 3521.934980: idpf_vport_stop
<-idpf_vport_dealloc
systemd-resolve-1633 [022] b..1. 3522.297299: idpf_set_rx_mode
<-dev_mc_del
systemd-resolve-1633 [022] b..1. 3522.297316: idpf_addr_unsync
<-__hw_addr_sync_dev
systemd-resolve-1633 [022] b..1. 3522.297317: idpf_del_mac_filter
<-idpf_addr_unsync
kworker/u261:2-3157 [037] ...1. 3522.297931:
idpf_mac_filter_async_handler: Received invalid MAC filter payload (op
536) (len 0)
rmmod-6089 [020] ..... 3522.573251: idpf_vport_stop
<-idpf_vport_dealloc
rmmod-6089 [002] ..... 3523.229936: idpf_vport_stop
<-idpf_vport_dealloc
systemd-resolve-1633 [022] b..1. 3523.311435: idpf_set_rx_mode
<-dev_mc_del
systemd-resolve-1633 [022] b..1. 3523.311452: idpf_addr_unsync
<-__hw_addr_sync_dev
systemd-resolve-1633 [022] b..1. 3523.311453: idpf_del_mac_filter
<-idpf_addr_unsync
next prev parent reply other threads:[~2025-10-07 0:07 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-10-02 0:14 [PATCH net 0/8] Intel Wired LAN Driver Updates 2025-10-01 (idpf, ixgbe, ixgbevf) Jacob Keller
2025-10-02 0:14 ` [PATCH net 1/8] idpf: cleanup remaining SKBs in PTP flows Jacob Keller
2025-10-02 0:14 ` [PATCH net 2/8] idpf: convert vport state to bitmap Jacob Keller
2025-10-02 0:14 ` [PATCH net 3/8] idpf: fix possible race in idpf_vport_stop() Jacob Keller
2025-10-03 17:43 ` Jakub Kicinski
2025-10-06 14:49 ` Tantilov, Emil S
2025-10-06 17:26 ` Jakub Kicinski
2025-10-07 0:07 ` Tantilov, Emil S [this message]
2025-10-08 21:41 ` Jacob Keller
2025-10-13 18:13 ` Jakub Kicinski
2025-10-22 22:49 ` Tantilov, Emil S
2025-10-02 0:14 ` [PATCH net 4/8] ixgbevf: fix getting link speed data for E610 devices Jacob Keller
2025-10-02 0:14 ` [PATCH net 5/8] ixgbe: handle IXGBE_VF_GET_PF_LINK_STATE mailbox operation Jacob Keller
2025-10-02 0:14 ` [PATCH net 6/8] ixgbevf: fix mailbox API compatibility by negotiating supported features Jacob Keller
2025-10-02 0:14 ` [PATCH net 7/8] ixgbe: handle IXGBE_VF_FEATURES_NEGOTIATE mbox cmd Jacob Keller
2025-10-02 0:14 ` [PATCH net 8/8] ixgbe: fix too early devlink_free() in ixgbe_remove() Jacob Keller
2025-10-03 17:42 ` [PATCH net 0/8] Intel Wired LAN Driver Updates 2025-10-01 (idpf, ixgbe, ixgbevf) Jakub Kicinski
2025-10-04 0:58 ` Jacob Keller
2025-10-06 15:27 ` Alexander Lobakin
2025-10-06 21:59 ` Jacob Keller
2025-10-06 23:58 ` Jacob Keller
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