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[144.49.247.125]) by smtp-relay.gmail.com with ESMTPS id af79cd13be357-93f70eae168sm4994985a.5.2026.10.22.15.06.48 for (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Thu, 22 Oct 2026 15:06:49 -0700 (PDT) X-Relaying-Domain: broadcom.com X-CFilter-Loop: Reflected Received: by mail-qt1-f199.google.com with SMTP id d75a77b69052e-53639e47be2so4064581cf.3 for ; Thu, 22 Oct 2026 15:06:48 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=broadcom.com; s=google; t=1792706808; x=1793311608; darn=vger.kernel.org; h=content-transfer-encoding:content-type:in-reply-to:autocrypt:from :content-language:references:cc:to:subject:user-agent:mime-version :date:message-id:from:to:cc:subject:date:message-id:reply-to :content-type; bh=Iia+/3SGKV6BH0FuXkiJp6KPLJIcRH5RkOpfzGcqdio=; b=g9KJ9C2+soB4zORwsKBW92UABfqqADgY2mxC7pYTqnmc11G0gxpiUgEytzqF55tmEA D7fKw9o+f0iSoesU61pxWCQPtPa3hIesuw+WDIoBdg1nZU+MRENxAggABnCiJz0mTX9s 6IegmS3kejn76oID82AtoYa6Tc4QTR2AasmBk= X-Forwarded-Encrypted: i=1; AKwUvBwBQ5FYyIPwOOD8kvjgYBlEuMvqCxHNLTP2buDQxFL+IBdlwa5IAEe3Vs/T8+71ftl9u2cNs8irO9mT5q8=@vger.kernel.org X-Received: by 2002:a05:622a:5c10:b0:516:ed02:c85d with SMTP id d75a77b69052e-536c2694d64mr4475491cf.3.1792706808563; Thu, 22 Oct 2026 15:06:48 -0700 (PDT) X-Received: by 2002:a05:622a:5c10:b0:516:ed02:c85d with SMTP id d75a77b69052e-536c2694d64mr4475031cf.3.1792706808133; Thu, 22 Oct 2026 15:06:48 -0700 (PDT) Received: from [10.67.48.245] ([192.19.223.252]) by smtp.gmail.com with ESMTPSA id d75a77b69052e-536c1835c23sm3113161cf.17.2026.10.22.15.06.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 22 Oct 2026 15:06:47 -0700 (PDT) Message-ID: <8b061dc1-73a9-4823-abb9-535eb4677b13@broadcom.com> Date: Thu, 22 Oct 2026 15:06:45 -0700 X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net] net: bgmac: rate limit RX error messages To: Rosen Penev , netdev@vger.kernel.org Cc: =?UTF-8?B?UmFmYcWCIE1pxYJlY2tp?= , Broadcom internal kernel review list , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Felix Fietkau , open list References: <20261018231629.39734-1-rosenp@gmail.com> Content-Language: en-US, fr-FR From: Florian Fainelli Autocrypt: addr=florian.fainelli@broadcom.com; keydata= xsBNBFPAG8ABCAC3EO02urEwipgbUNJ1r6oI2Vr/+uE389lSEShN2PmL3MVnzhViSAtrYxeT M0Txqn1tOWoIc4QUl6Ggqf5KP6FoRkCrgMMTnUAINsINYXK+3OLe7HjP10h2jDRX4Ajs4Ghs JrZOBru6rH0YrgAhr6O5gG7NE1jhly+EsOa2MpwOiXO4DE/YKZGuVe6Bh87WqmILs9KvnNrQ PcycQnYKTVpqE95d4M824M5cuRB6D1GrYovCsjA9uxo22kPdOoQRAu5gBBn3AdtALFyQj9DQ KQuc39/i/Kt6XLZ/RsBc6qLs+p+JnEuPJngTSfWvzGjpx0nkwCMi4yBb+xk7Hki4kEslABEB AAHNMEZsb3JpYW4gRmFpbmVsbGkgPGZsb3JpYW4uZmFpbmVsbGlAYnJvYWRjb20uY29tPsLB IQQQAQgAywUCZWl41AUJI+Jo+hcKAAG/SMv+fS3xUQWa0NryPuoRGjsA3SAUAAAAAAAWAAFr ZXktdXNhZ2UtbWFza0BwZ3AuY29tjDAUgAAAAAAgAAdwcmVmZXJyZWQtZW1haWwtZW5jb2Rp bmdAcGdwLmNvbXBncG1pbWUICwkIBwMCAQoFF4AAAAAZGGxkYXA6Ly9rZXlzLmJyb2FkY29t Lm5ldAUbAwAAAAMWAgEFHgEAAAAEFQgJChYhBNXZKpfnkVze1+R8aIExtcQpvGagAAoJEIEx tcQpvGagWPEH/2l0DNr9QkTwJUxOoP9wgHfmVhqc0ZlDsBFv91I3BbhGKI5UATbipKNqG13Z TsBrJHcrnCqnTRS+8n9/myOF0ng2A4YT0EJnayzHugXm+hrkO5O9UEPJ8a+0553VqyoFhHqA zjxj8fUu1px5cbb4R9G4UAySqyeLLeqnYLCKb4+GklGSBGsLMYvLmIDNYlkhMdnnzsSUAS61 WJYW6jjnzMwuKJ0ZHv7xZvSHyhIsFRiYiEs44kiYjbUUMcXor/uLEuTIazGrE3MahuGdjpT2 IOjoMiTsbMc0yfhHp6G/2E769oDXMVxCCbMVpA+LUtVIQEA+8Zr6mX0Yk4nDS7OiBlvOwE0E U8AbwQEIAKxr71oqe+0+MYCc7WafWEcpQHFUwvYLcdBoOnmJPxDwDRpvU5LhqSPvk/yJdh9k 4xUDQu3rm1qIW2I9Puk5n/Jz/lZsqGw8T13DKyu8eMcvaA/irm9lX9El27DPHy/0qsxmxVmU pu9y9S+BmaMb2CM9IuyxMWEl9ruWFS2jAWh/R8CrdnL6+zLk60R7XGzmSJqF09vYNlJ6Bdbs MWDXkYWWP5Ub1ZJGNJQ4qT7g8IN0qXxzLQsmz6tbgLMEHYBGx80bBF8AkdThd6SLhreCN7Uh IR/5NXGqotAZao2xlDpJLuOMQtoH9WVNuuxQQZHVd8if+yp6yRJ5DAmIUt5CCPcAEQEAAcLB gQQYAQIBKwUCU8AbwgUbDAAAAMBdIAQZAQgABgUCU8AbwQAKCRCTYAaomC8PVQ0VCACWk3n+ obFABEp5Rg6Qvspi9kWXcwCcfZV41OIYWhXMoc57ssjCand5noZi8bKg0bxw4qsg+9cNgZ3P N/DFWcNKcAT3Z2/4fTnJqdJS//YcEhlr8uGs+ZWFcqAPbteFCM4dGDRruo69IrHfyyQGx16s CcFlrN8vD066RKevFepb/ml7eYEdN5SRALyEdQMKeCSf3mectdoECEqdF/MWpfWIYQ1hEfdm C2Kztm+h3Nkt9ZQLqc3wsPJZmbD9T0c9Rphfypgw/SfTf2/CHoYVkKqwUIzI59itl5Lze+R5 wDByhWHx2Ud2R7SudmT9XK1e0x7W7a5z11Q6vrzuED5nQvkhAAoJEIExtcQpvGagugcIAJd5 EYe6KM6Y6RvI6TvHp+QgbU5dxvjqSiSvam0Ms3QrLidCtantcGT2Wz/2PlbZqkoJxMQc40rb fXa4xQSvJYj0GWpadrDJUvUu3LEsunDCxdWrmbmwGRKqZraV2oG7YEddmDqOe0Xm/NxeSobc MIlnaE6V0U8f5zNHB7Y46yJjjYT/Ds1TJo3pvwevDWPvv6rdBeV07D9s43frUS6xYd1uFxHC 7dZYWJjZmyUf5evr1W1gCgwLXG0PEi9n3qmz1lelQ8lSocmvxBKtMbX/OKhAfuP/iIwnTsww 95A2SaPiQZA51NywV8OFgsN0ITl2PlZ4Tp9hHERDe6nQCsNI/Us= In-Reply-To: <20261018231629.39734-1-rosenp@gmail.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-DetectorID-Processed: b00c1d49-9d2e-4205-b15f-d015386d3d5e On 10/18/26 16:16, Rosen Penev wrote: > When the RX ring is full the RX FIFO overflows. With RX overflow > continue enabled, the DMA engine then writes one frame with a bogus > length (always 0x45c2 on a BCM4716), which the driver drops with > "Found oversized packet at slot %d, DMA issue!". > > Under sustained overload this happens on every NAPI poll. On an Asus > RT-N16 a 950 Mbit/s UDP stream to the router printed about 1450 such > lines in 20 seconds. The messages are printed from NAPI context, so > with a serial console the router spends most of its time printing. > > The frames are already accounted in rx_length_errors and rx_errors. > Rate limit both RX error messages. With this change the same flood > printed 60 lines while rx_length_errors counted 14297 dropped frames. > > Fixes: 6a6c708469c9 ("bgmac: add check for oversized packets") > Signed-off-by: Rosen Penev > --- > drivers/net/ethernet/broadcom/bgmac.c | 10 ++++++---- > 1 file changed, 6 insertions(+), 4 deletions(-) > > diff --git a/drivers/net/ethernet/broadcom/bgmac.c b/drivers/net/ethernet/broadcom/bgmac.c > index 1835266fdd09..b3a92ae95de3 100644 > --- a/drivers/net/ethernet/broadcom/bgmac.c > +++ b/drivers/net/ethernet/broadcom/bgmac.c > @@ -447,16 +447,18 @@ static int bgmac_dma_rx_read(struct bgmac *bgmac, struct bgmac_dma_ring *ring, > > /* Check for poison and drop or pass the packet */ > if (len == 0xdead && flags == 0xbeef) { > - netdev_err(bgmac->net_dev, "Found poisoned packet at slot %d, DMA issue!\n", > - ring->start); > + if (net_ratelimit()) > + netdev_err(bgmac->net_dev, "Found poisoned packet at slot %d, DMA issue!\n", > + ring->start); > put_page(virt_to_head_page(buf)); > bgmac->net_dev->stats.rx_errors++; > break; > } > > if (len > BGMAC_RX_ALLOC_SIZE) { > - netdev_err(bgmac->net_dev, "Found oversized packet at slot %d, DMA issue!\n", > - ring->start); > + if (net_ratelimit()) > + netdev_err(bgmac->net_dev, "Found oversized packet at slot %d, DMA issue!\n", > + ring->start); No objection, but the issue is that we are going over BGMAC_RX_ALLOC_SIZE, and I believe the check should actually be BGMAC_RX_MAX_FRAME_SIZE because we have the skb_shared_info at the end of the packet, if we start overflowing that, we will call skb_over_panic() very soon. -- Florian