From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=74.125.224.41 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1794583271; b=E9x6pGnnAGAXnJtjk4nA5MukeKC/+rz9h6gP9jIOr7KxQLhaKMI+sAyVZe7U6PIlHt8m F7+C9ys7PcivcKqAtM/JpSu2PkLLuDd0rLIgpFt/zLT3ddB4j6h7meZEZHQf+E7V8RD9h XD2rWLfIvtAMsvO65OgTXhHSpG+Wo9sXOZwVT8GKGsv96V5pPwPTWben0em/uJYczDDKm Yr9fHclBozMSuGU1HdyJRMEbeafgd6h9kzTqjE7t41BtsO99wvosNn6WrQlM51FlXuX4f NcBunRLTekF29Ri2QF1xkLlJUYZyQboM1XFUp1qozc9NCVqdlBQR8gBXYLvmE3Q8wPQ== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1794583271; h=DMARC-Filter:Received:X-Google-DKIM-Signature:X-Forwarded-Encrypted: X-Gm-Message-State:X-Gm-Gg:X-Received:Received:Date:From:To:Cc: Subject:Message-ID:References:MIME-Version:Content-Type: Content-Disposition:In-Reply-To; bh=OjIDt+f/7+dWlNv53r9qvEutgjmi1ked15ytPMp8nBU=; b=rYv1SooK+JWRyRH3JohG67B4DGRzrdJ/oCtbd4teM6p2DQR+5RW2ojKEjnPg9u3L6QCO l+PIZuZxVZ36uUP+JtdFjzRfAIqMJ6IADv3kHv5Db0Dt9EzZhq+fBaCeZki6lG9vLl+4G 4mpJdGBVhYERbox86UFuH+54Sa0ZCLeFJU/dbSxiuf1saYRqDWZXZM5X2Xv0Ga1yl4RmF RJAc6akiY7LuChnNaEy9+z49gwyuF3uXQCZmuEOMl0KzAJOK3vN9eGN9dpr/r4+BHk4Eu d7qfnBNug2lFJ/kyNH1Ykqf//d29WY40BG8VMfC/AveaZXRCuSd3xOKsCmvxLeeAVVg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=fail header.from=debian.org; spf=pass smtp.mailfrom=gmail.com; arc=none smtp.remote-ip=74.125.224.41 Received: from mail-yx1-f41.google.com (mail-yx1-f41.google.com [74.125.224.41]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5E773606A32E for ; Fri, 13 Nov 2026 15:21:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 5E773606A32E Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=debian.org Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Received: by mail-yx1-f41.google.com with SMTP id 956f58d0204a3-67bee1f693bso888631d50.1 for ; Fri, 13 Nov 2026 07:21:11 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1794583270; x=1795188070; h=in-reply-to:content-disposition:content-type:mime-version :references:message-id:subject:cc:to:from:date:x-gm-gg :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to :content-type; bh=OjIDt+f/7+dWlNv53r9qvEutgjmi1ked15ytPMp8nBU=; b=hlx2vKXwVd0c8BAE4FHvKRT6RHyyQnXELPKGyqaS6ACMk7pyMaUFl83f//iVM10jMg ExCGH0FM0GVh7CPNW5Biiv/eN0mbMGPTScofnhWDUFQgQ9iCKzQ8BYIU+Bjh2GeWGksx FSziyiqozPHAwptQHe2gHQFK7oj8Nqzmml9d9p72O8RVsCfQhEpojXiU4Zi97mA+KvG8 My9vcLE0z1c3MKLncSUC+dzryjuVfcu9ipkpKfOR7CleVBVkZUblHbU9rXyBYvfcsO6X Bo7kJCMediEd48kOyU8sK4SohF2q6l8h90rI8X6z6Eq1RcFRPt87OZS/96qCpaWgImXs DfYw== X-Forwarded-Encrypted: i=1; AL+hErHuXtloIlotvHvHcxmpmeiQysx0c9GPlykaEi8D+548XNoT2HtIWiX2L96g9F9mF+qgy1E0dlIxtC15nddTZg==@lists.linux.dev X-Gm-Message-State: APuU4Z8QPdxNSChXF9XcDJzsMVLjky2a00kD32otiB1ONz2SERoz88ek DM+Y8Yoys7O+rg3ihFwLreQmQem+4BGYBkIsw7uqK1brKIuQ88Zxgm13 X-Gm-Gg: AYBFou0+GK5EIM01dJdPNmbKGfwgtcb514u26BKYsmQ0FNrTR3S8ACkllCkZKJ/+w89 K51SOeEQHgk0OTv/6VOIaz71YXzfKfbHIDf8yxVVAfRZlFlVgIS83pRavoTwhpac1wbW52UBFZW fmhKUD3ZwO05Ewf8NerZGe0OweugP/yusO1SnPUKEaNm+U/uzjq0Pm9gix7k2BCmS0ER3tKDM4N WatZlQSOcxYXUDkiZ6OqpoSZ3d+YUuI/YNFt9VIgF10O6d8G6WgT/zNo6ZBEtlv67k52tna3wwB jn7WecAz5YU/W3v9YVEPX+yQ4c1j/Xts3SjzTPhSrkKts2ggAzUzMITyTxqJPAhYkn9jlQv9I4o 1/jxmSrpf7NWfDdDsvBz7Vl/USWcBDTrEXFUoH41Pn9QhuAGPvknGSEjig6RE7dGVRTqWCWpPPe 3CEZvGov96gplKjxXc0m5F1vg5QuLnViOh4OXqp2Zvvctyocvv8NC0KCOA18bWKHQzZEPX4EsEu WpSNioZWGOwclJTnMVv09iCQWymoSpGnAed0REwot53onDltSQ9yymqjbpNO9jJB/zlITa5q5qq gSCO3ERtvktcfEOSbxSz X-Received: by 2002:a05:690e:4503:10b0:67c:2b34:319c with SMTP id 956f58d0204a3-67d897f540dmr1252728d50.78.1794583270342; Fri, 13 Nov 2026 07:21:10 -0800 (PST) Received: from gmail.com ([2a03:2880:24ff:4e::]) by smtp.gmail.com with ESMTPSA id 956f58d0204a3-67d8a629a2dsm2307745d50.21.2026.11.13.07.21.07 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Nov 2026 07:21:07 -0800 (PST) Date: Fri, 13 Nov 2026 07:21:06 -0800 From: Breno Leitao To: Sebastian Andrzej Siewior Cc: Karl Mehltretter , netdev@vger.kernel.org, "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Clark Williams , Steven Rostedt , Stephen Hemminger , Arend van Spriel , linux-kernel@vger.kernel.org, linux-rt-devel@lists.linux.dev Subject: Re: [PATCH net v2 1/2] netpoll: use a raw lock for the deferred transmit queue Message-ID: References: <20260928064239.32456-1-kmehltretter@gmail.com> <20260930192103.62973-2-kmehltretter@gmail.com> <20261001074819.gQ3w8q6P@linutronix.de> <20261009155225.6Uy7b0wd@linutronix.de> X-Mailing-List: linux-rt-devel@lists.linux.dev List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20261009155225.6Uy7b0wd@linutronix.de> Hello Sebastian, On Fri, Oct 09, 2026 at 05:52:25PM +0200, Sebastian Andrzej Siewior wrote: > I would suggest to untangle that local-irq-disable assumption. Then we > end up with the ::write_atomic callback on PREEMPT_RT which will raise > warnings. But those will appear only on panic() and as the last console > due to CON_NBCON_ATOMIC_UNSAFE so everything will go according to the > plan. > On !RT the whole __netpoll_send_skb() will be with disabled interrupts > due to the console lock. On RT it won't and I don't know if anything > down the call chain assumes that. Thanks for the patch, On PREEMPT_RT, the send path is clean. all the selftest I have are passing fine, without a single splat, while the unpatched kernel produces about a dozen over the same tests. On !RT, the first message triggers, but it doesn't seem a big deal. WARNING: kernel/softirq.c:453 at __local_bh_enable_ip+0x118/0x120, CPU#4: pr/netcons_netc/307 ... Call trace: __local_bh_enable_ip+0x118/0x120 (P) netpoll_send_skb+0x1a8/0x364 send_udp+0x348/0x4a8 netconsole_write+0x16c/0x628 nbcon_emit_next_record+0x150/0x3cc nbcon_emit_one+0x74/0x158 nbcon_kthread_func+0x18c/0x258 kthread+0x108/0x134 Anyway, is this patch something you are planning to send officially? Thanks, --breno