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Message-ID: <4f9e7d31-7c73-e5c1-b34c-3924c5d6b100@linux.intel.com>
Date:   Wed, 13 Sep 2023 13:56:10 +0300
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Subject: Re: [Intel-wired-lan] [PATCH iwl-net v2] igc: Fix infinite
 initialization loop with early XDP redirect
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To:     Vinicius Costa Gomes <vinicius.gomes@intel.com>,
        intel-wired-lan@lists.osuosl.org
Cc:     Andre Guedes <andre.guedes@intel.com>, netdev@vger.kernel.org,
        Jesse Brandeburg <jesse.brandeburg@intel.com>,
        Jithu Joseph <jithu.joseph@intel.com>,
        linux-kernel@vger.kernel.org,
        Ferenc Fejes <ferenc.fejes@ericsson.com>,
        Eric Dumazet <edumazet@google.com>,
        Tony Nguyen <anthony.l.nguyen@intel.com>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>,
        "David S. Miller" <davem@davemloft.net>,
        Vedang Patel <vedang.patel@intel.com>
References: <20230907003005.99481-1-vinicius.gomes@intel.com>
From:   "naamax.meir" <naamax.meir@linux.intel.com>
In-Reply-To: <20230907003005.99481-1-vinicius.gomes@intel.com>
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On 9/7/2023 03:30, Vinicius Costa Gomes wrote:
> When a XDP redirect happens before the link is ready, that
> transmission will not finish and will timeout, causing an adapter
> reset. If the redirects do not stop, the adapter will not stop
> resetting.
> 
> Wait for the driver to signal that there's a carrier before allowing
> transmissions to proceed.
> 
> Previous code was relying that when __IGC_DOWN is cleared, the NIC is
> ready to transmit as all the queues are ready, what happens is that
> the carrier presence will only be signaled later, after the watchdog
> workqueue has a chance to run. And during this interval (between
> clearing __IGC_DOWN and the watchdog running) if any transmission
> happens the timeout is emitted (detected by igc_tx_timeout()) which
> causes the reset, with the potential for the inifite loop.
> 
> Fixes: 4ff320361092 ("igc: Add support for XDP_REDIRECT action")
> Reported-by: Ferenc Fejes <ferenc.fejes@ericsson.com>
> Closes: https://lore.kernel.org/netdev/0caf33cf6adb3a5bf137eeaa20e89b167c9986d5.camel@ericsson.com/
> Signed-off-by: Vinicius Costa Gomes <vinicius.gomes@intel.com>
> Tested-by: Ferenc Fejes <ferenc.fejes@ericsson.com>
> Reviewed-by: Maciej Fijalkowski <maciej.fijalkowski@intel.com>
> ---
> v1 -> v2:
>   - Added more information to the commit message (Maciej Fijalkowski)
> 
> 
>   drivers/net/ethernet/intel/igc/igc_main.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)

Tested-by: Naama Meir <naamax.meir@linux.intel.com>