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Miller" , Jakub Kicinski , Paolo Abeni , Maxime Coquelin , Alexandre Torgue , "Russell King (Oracle)" , Nazim Amirul , netdev@vger.kernel.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org References: <20261102080938.2955-1-magnusleatti@kernelriot.com> Content-Language: en-US From: Maxime Chevallier In-Reply-To: <20261102080938.2955-1-magnusleatti@kernelriot.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Last-TLS-Session-Version: TLSv1.3 Hi Magnus, On 11/2/26 09:09, Magnus Leatti wrote: > motorcomm_init() writes 0 to MGMT_INT_CTRL0, which unmasks the MISC > interrupt. MISC arrives on MSI-X vector 5, which stmmac requests as its > MAC interrupt, and nothing in stmmac clears it. The vendor driver masks > it. > > Since commit 1b9707e6f1a9 ("net: stmmac: enable RPS and RBU interrupts"), > heavy RX load sets MISC and it never clears again, even though every > status register I could find reads zero. Vector 5 then fires about 120k > times per second and the machine stops responding until the TX watchdog > resets the adapter, or does not recover at all. A 64-byte UDP flood > from another host is enough: > > iperf3 -c -u -b 0 -l 64 -R -P 4 -t 10 > > Mask MISC, as the vendor driver does. I could not find anything else > that depends on it here: EEE is not supported, and Wake-on-LAN uses PME. > > Tested on one YT6801 board with net at cb284914e749. Without this > patch the flood above hangs the board within a second. With it, no MAC > interrupt fires under that flood or heavier ones, including after link, > ring, MTU and speed changes and a module reload, and throughput is > unchanged. Suspend could not be tested. The register values were read > with a debug build of stmmac. > > Fixes: 02ff155ea281 ("net: stmmac: Add glue driver for Motorcomm YT6801 ethernet controller") > Signed-off-by: Magnus Leatti Can you test this, sent a few days ago ? I also saw that storm, but it didn't seem to be motorcomm specific : https://lore.kernel.org/r/20261030102251.208929-1-maxime.chevallier@bootlin.com It should address the issue, doesn't require masking MISC entirely, and isn't motorcomm specific (this storm will happen on all dwmac4 multi-MSI glues). > --- > Russell, d3265c19b35d ("net: stmmac: xgmac2: disable RBUE in default RX > interrupt mask") describes a similar storm on xgmac2. Should dwmac4 do > the same? I have only tested the glue change. The above patch should handle these too on dwmac4 :) Thanks, Maxime