From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D9E83189F4B for ; Thu, 24 Oct 2024 08:47:38 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729759658; cv=none; b=m8wP4yIhrUP6sjWxm8jUdWT9QcQ18vsyQoFKAhldRED0mqSiIQxMfA1YY4Y4vePS4s+iBBf5poMv0L/SHrg/Z2DkPWeyR8ULAZRIBX1XXQKXOEjO6qN3n82h9gQPW/FsE7UK7LTM38jAWnB+iPvFQ6bAMuI5AsiO+5jUIBnxPO0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1729759658; c=relaxed/simple; bh=XShdbifM8rPpMICCTPs3OkzOAyfBxFO3evEa2zTnfd4=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=KmrXxvlOrwvYg9JLuQU2c6VhJpBAF9mh6frT7VVmOr7k1z8tY+vC2N1Tmo3aPl938EQ+nHsCasxwhBuscC914jR58vnX6Wqrm0/PO7f4Mp7CfcakqnTLg2xtuHw0b3nuhaQrDjI6vypWVo8OX7F3Nuya06z/SACIc6bVzEIvpvc= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=eI9QUpc+; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="eI9QUpc+" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D3AD9C4CEC7; Thu, 24 Oct 2024 08:47:34 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1729759658; bh=XShdbifM8rPpMICCTPs3OkzOAyfBxFO3evEa2zTnfd4=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=eI9QUpc+aC6nDAu3KMLELxzjvO4Xw4pKDllMTBcvoeh7rUEO5k3MRCrHpdhnQsTS7 +7GUVsmVViMRSoWTYasrBxmVxJq4aTM3HmMHCAzFD7MpveNn9lstqXjZupxXHsAObI 8qdVXzGIR+atlOuuBjdM5DYuepDAlthqTuAGowPuUuKrPlyRNHJUu9D79yBy1ZTipG ofE+E5RejvpCfF3s/d/+IH1WTEtbidzm+r0fHs8fbdqwf7GYST2xHO08fBDfy35JcR A1fnwWlppH9xIR60mAmyo1JOCJG3YaVkf26CXqHpJIbRYXBLMpFM257Q6X4hZhBlBr u6zfZDfUJTIbA== Date: Thu, 24 Oct 2024 09:47:32 +0100 From: Simon Horman To: Jacob Keller Cc: Przemek Kitszel , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Jeff Garzik , Michal Swiatkowski , Piotr Raczynski , Vadim Fedorenko , Milena Olech , Arkadiusz Kubalewski , Michal Michalik , netdev , Jiri Pirko , Wander Lairson Costa , Yuying Ma , Rafal Romanowski Subject: Re: [PATCH net 1/3] igb: Disable threaded IRQ for igb_msix_other Message-ID: <20241024084732.GE402847@kernel.org> References: <20241021-iwl-2024-10-21-iwl-net-fixes-v1-0-a50cb3059f55@intel.com> <20241021-iwl-2024-10-21-iwl-net-fixes-v1-1-a50cb3059f55@intel.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241021-iwl-2024-10-21-iwl-net-fixes-v1-1-a50cb3059f55@intel.com> On Mon, Oct 21, 2024 at 04:26:24PM -0700, Jacob Keller wrote: > From: Wander Lairson Costa > > During testing of SR-IOV, Red Hat QE encountered an issue where the > ip link up command intermittently fails for the igbvf interfaces when > using the PREEMPT_RT variant. Investigation revealed that > e1000_write_posted_mbx returns an error due to the lack of an ACK > from e1000_poll_for_ack. > > The underlying issue arises from the fact that IRQs are threaded by > default under PREEMPT_RT. While the exact hardware details are not > available, it appears that the IRQ handled by igb_msix_other must > be processed before e1000_poll_for_ack times out. However, > e1000_write_posted_mbx is called with preemption disabled, leading > to a scenario where the IRQ is serviced only after the failure of > e1000_write_posted_mbx. > > To resolve this, we set IRQF_NO_THREAD for the affected interrupt, > ensuring that the kernel handles it immediately, thereby preventing > the aforementioned error. > > Reproducer: > > #!/bin/bash > > # echo 2 > /sys/class/net/ens14f0/device/sriov_numvfs > ipaddr_vlan=3 > nic_test=ens14f0 > vf=${nic_test}v0 > > while true; do > ip link set ${nic_test} mtu 1500 > ip link set ${vf} mtu 1500 > ip link set $vf up > ip link set ${nic_test} vf 0 vlan ${ipaddr_vlan} > ip addr add 172.30.${ipaddr_vlan}.1/24 dev ${vf} > ip addr add 2021:db8:${ipaddr_vlan}::1/64 dev ${vf} > if ! ip link show $vf | grep 'state UP'; then > echo 'Error found' > break > fi > ip link set $vf down > done > > Signed-off-by: Wander Lairson Costa > Fixes: 9d5c824399de ("igb: PCI-Express 82575 Gigabit Ethernet driver") > Reported-by: Yuying Ma > Reviewed-by: Przemek Kitszel > Tested-by: Rafal Romanowski > Signed-off-by: Jacob Keller Reviewed-by: Simon Horman