From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=100.103.45.18 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1792486758; b=e9mr7NoMybQ0uiGL5He9yakiNntcxAviQZAkd3ZbUSn5wEGLDgIGWL817AJ+VgH09Kru I4v7YPV0Gu2FCUoP6lW5LcFGmelwdu60E5z0gsqNl+N2jzUWZGP6PzFaIutnfNzn73se3 pbWS1fn0+GZqJ7YKaKwvahkdqXnOMbVMeUiI3XhZ1PVTik494MP69o1H1dXK2B75XOOQ+ lyrZbx9vQr4awa7ylMD2vDdIPe9o5zkT9CKXmfSmkOktfSZ7S4PaiEIFVMXd1Yf8cTppC h6XVnp/44bme1BLBw3vpkhiuqr4uHYSdRSTs2vYwXeWyGUJa/XKVLeMu1fxVu5dc2rA== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1792486758; h=Received:DKIM-Signature:Message-ID:From:Subject:Reply-To:To:Cc: In-Reply-To:References:Content-Type:Content-Transfer-Encoding:Date; bh=/cSNwYfgZ4wkv/7/VwPSvsHFuEnCWUKwmBdTfOzdEX4=; b=ETA32PCTG882SWtUEMDWMY+NAnQQE9tMNSFYeHTBhjcj+JaWhNqYsIgNKuwiiJAqzIQA 8Z7WWCZMQggPV/dLBLSO6UPI0jGSLf75LN+MBSxfFWCKjFudImJdVVrg/30K7xM8M8dcX MhXSaUm2lwXM4Ziyxq9snKpmJ5OZ+yndbRA1fJkleCcUyGG9ISTODzxrLZfuUhK/MiL3e ScJjooUZjqiIvIF5lnjUV1KSYHeecv9Jo5twnwrO9ihtso7QRk0gG4WlB8Uid2p0a5OSM K4AIw+CoMU1iV5tWsOiKFECJTFvdPPXLODmnUsA1wwO85Z27rgFHbgFT3WnC3H2AQZg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XFUsZ6m3; arc=none smtp.remote-ip=100.103.45.18 Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 3C836606A319 for ; Tue, 20 Oct 2026 08:59:18 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=kernel.org header.i=@kernel.org header.a=rsa-sha256 header.s=k20260515 header.b=XFUsZ6m3 Received: by smtp.kernel.org (Postfix) with ESMTPSA id CC1851F000C5; Tue, 20 Oct 2026 08:59:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1792486758; bh=/cSNwYfgZ4wkv/7/VwPSvsHFuEnCWUKwmBdTfOzdEX4=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=XFUsZ6m3MbEYtp59cnWUzp+21HJWnPMEwLhEIq/S8beggTQ0dBZjUtbuFflZHozEZ plYCZ6f2M3UCVTOl0cd9ZsGpECm0bErTsA/PjPaaQV3RyiEqgzzeNSybn/4mrNubDO gshlorPZy07KdCtqxICRnY6pwL6VqWGCdwCEGru1HbqIXlZ2ButvKxBtQUpI4ZjbVu ZcsDvUPN4BhhZ5iW/khI4sfcx6oVdtynQM1GpIJNTqZISwq2f4/pdr5KTbz90EuR9e BvkdOwg1LfjPE+Xnolzaa7BIRg21MKDvXZCdKyBm0nEscrU1r12axoeDixhhqaycCy zDDSd0FcjzJaQ== Message-ID: From: sashiko-bot@kernel.org Subject: Re: [PATCH net 1/2] net: usb: cdc_ncm: don't enable BHs in tx_fixup under netpoll Reply-To: sashiko-reviews@lists.linux.dev To: "Nicolai Buchwitz" Cc: linux-usb@vger.kernel.org In-Reply-To: <20261020-cdc-ncm-netpoll-v1-1-682184384b49@tipi-net.de> References: <20261020-cdc-ncm-netpoll-v1-0-682184384b49@tipi-net.de> <20261020-cdc-ncm-netpoll-v1-1-682184384b49@tipi-net.de> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 20 Oct 2026 08:59:17 +0000 X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list > netpoll holds the txq lock and calls ndo_start_xmit() with IRQs off but > BHs on. The spin_unlock_bh() in cdc_ncm_tx_fixup() then runs pending > softirqs. If one of them transmits, it spins on the txq lock that > netpoll holds. With netconsole on a cdc_ncm device this ends in a soft > or hard lockup. >=20 > Use spin_lock_irqsave(), which is safe both under netpoll and on the > normal xmit path. >=20 > Fixes: c84ff1d6dff3 ("cdc_ncm: reduce driver latency in the data path") > Reported-by: Mikkel Eskildsen > Closes: https://lore.kernel.org/netdev/PRAP189MB185019A5A8D411482BB6E0CDA= 9982@PRAP189MB1850.EURP189.PROD.OUTLOOK.COM/ > Tested-by: Mikkel Eskildsen > Signed-off-by: Nicolai Buchwitz Sashiko has reviewed this patch and found no issues. --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20261020-cdc-ncm-ne= tpoll-v1-0-682184384b49@tipi-net.de?part=3D1