From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 A8D7535E923; Tue, 16 Jun 2026 15:31:26 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781623888; cv=none; b=SIdb8RRuo5P8Y+2xJkJVG37ajc2pnoMppiRxbmW3+tEDGh/JVq79j8OisljLCdl9RU+7TEi2YpZXLso3c7hfQc+7cysLCMOHhLfdPE7zJdroNvYMjpfCJIYHPHUX/ej74/v5QEnXMjPdmMlP4w1LWH67oUyAjDs6Za0P1lvgVt8= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1781623888; c=relaxed/simple; bh=sJViFkfm/ekIWg/yU29S/8y7sjVwRMKZ3zuMz1uu4Ck=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=r8VxegRYEb/X9cQm6MtRLyA6xwht9+lYyoxvyFbzars/ZL8FGFGUZPdOQ0mS9YR8xNLtac/+Oesq9WMPNNH/RKxQ6tSgtp2OpMuM9pNR54stHIlxXsyXD+OinrKI/LcL2fMEHzwxeNK2wQIFu07dA7Md/Q6VBnRDopwZbr7d0NU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=3D7V5a7N; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=iCO1r8rC; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="3D7V5a7N"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="iCO1r8rC" Date: Tue, 16 Jun 2026 17:31:22 +0200 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1781623884; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=FTBREjQ1CMm+3pVbDHQG4MDlL3sfISBDUsIUWQVi69A=; b=3D7V5a7Nw/0QNcsdFn8g1mGRWtyJdw3uPLCSWIH6WyKta76gaNHzUwJ6gOGze5bJ35dQmo zAaUvm1MWebK9ewP3U2qqrayUUczV4MeVYronPhznRNuu/xiP/uSq6g+Iby7mpQ8M+bbgr KLsaQ8Egf4V/9gerAVlOkdenn9n2CnUtlwiv40PfGrWOnHkkOiSs8iMhSDi5CGOzNWPFKU /i6VG9MFZ5SIRFwk7wiOt57x5U0m83ch3jji2mrwsHJ6ZWC1cNDAWTxnuOtvS07pxB0tZA aEtlOilzUJxsas6Rarw7N4sKUGwRj5JSfjYIugz4n8VE+9RzBY1YV4PqOjOTHg== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1781623884; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=FTBREjQ1CMm+3pVbDHQG4MDlL3sfISBDUsIUWQVi69A=; b=iCO1r8rCnUXgcw/r1g3zthUBwI2wr/K5thRZ3iBTpZjGRSEO4go4GAX+6fl802MGQQ19mJ q0m3/BH/hEsawxAw== From: Sebastian Andrzej Siewior To: Jakub Kicinski Cc: Petr Mladek , John Ogness , Sergey Senozhatsky , Peter Zijlstra , Vlad Poenaru , Thomas Gleixner , netdev@vger.kernel.org, "David S . Miller" , Eric Dumazet , Paolo Abeni , Simon Horman , Breno Leitao , Clark Williams , Steven Rostedt , linux-rt-devel@lists.linux.dev, linux-kernel@vger.kernel.org, stable@vger.kernel.org, Frederic Weisbecker , Ingo Molnar , Vincent Guittot , Dietmar Eggemann , K Prateek Nayak Subject: Re: [PATCH net] netpoll: run NAPI poll in softirq context to avoid rq->lock self-deadlock Message-ID: <20260616153122.keHMKvVT@linutronix.de> References: <20260610183621.3915271-1-vlad.wing@gmail.com> <20260611191114.5bc43a59@kernel.org> <20260616103529.Yh9Dxsjp@linutronix.de> <20260616081128.04e2c8dd@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20260616081128.04e2c8dd@kernel.org> On 2026-06-16 08:11:28 [-0700], Jakub Kicinski wrote: > > > > Adding sched and printk folks for opinions while eyeballing > > WARN_ON_DEFERRED(). > > Thanks a lot for looking into this! To be clear - the printk_deferred / > WARN_DEFERRED would be just for stable? Or there's still some > sensitivity even with nbcon? We already have printk_deferred(). WARN_DEFERRED() would be new. I *think* this is not limited netpoll/ netconsole but all console drivers not using CON_NBCON if the printk (via WARN) occurs with the rq held. I don't remember all the details but printk_deferred() was introduced to circumvent this until printk is fixed. Once we get rid of those legacy drivers and NBCON is the default we can get rid of printk_deferred() :) Sebastian