From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-lj1-f175.google.com (mail-lj1-f175.google.com [209.85.208.175]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D535415687D for ; Mon, 16 Sep 2024 14:33:58 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=209.85.208.175 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726497240; cv=none; b=gHbXuQFC7OJoOuGPoXRYhdoPVJs656xYXIyJDAXnUdT1u4UQfHOc4N/4kql8jiGUUSfvGPL7EocJ8/PmBCQvtltWrRaAgR8uUBesiThZaRXPkRE/1nSV7wV7/wTFaVHOpjYtbq/Lxfu40iYD3qoar2xXhMp4Y6BeMBKTCOsmlNg= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1726497240; c=relaxed/simple; bh=2O9dKB4M9hPrzdEfalRnI9e3/lZkTd8mT9vuyC01V4U=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=t5qapCJmwUmGSBkGwAGc59GVt8GfBW1gD6BIIo9iZnkEWPuu9vfH7IcCn0QNjAxNy12fy8+tOTwdyblYUi5ty7bOIUNFSYPR+RbxzFHRXZwSATj0n8bJzU5bHIl7p1FFc/gN/z0wER6YHuP+V6jzPlL1BwfFRC8zhYauNiY+2/Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com; spf=pass smtp.mailfrom=suse.com; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b=UGVcvnW6; arc=none smtp.client-ip=209.85.208.175 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=quarantine dis=none) header.from=suse.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=suse.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=suse.com header.i=@suse.com header.b="UGVcvnW6" Received: by mail-lj1-f175.google.com with SMTP id 38308e7fff4ca-2f760f7e25bso43932931fa.2 for ; Mon, 16 Sep 2024 07:33:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=google; t=1726497237; x=1727102037; darn=vger.kernel.org; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=rT7fkfgKvdnxFcCjnHIHT63TtCsP/eoL84gnJAKgmpM=; b=UGVcvnW6XvdNJQ/XPMZGDzhzoy6Uq/LQ/hjNp5htk5Kr/kAh/J5NCgX5HUa7PsaWgH PmL3mRz8eWUeDvdpLlCNg38iOU/QP0YxqDvDAjhd2Sl2av612/0DbN6X47rkYkkVgJGe HIoJRq4lhR1mUYiSCeUNLMPSdt9MFz+d7Uk/ewawv0iyQ5lZud+/OluCNuPhCUYYH7kq lWuG/ZJCYCfEaaoVdiX3q2uqDaQB7boRLayflpDzgoA3NGInGHv+SOKhPNytZZfQ/hvl v1MJhD0vLF3upJpHEbzRkhgFCrsuARThamOS2SdOLpNlMn91bXcvPm7eb8To5KJA1cXk 7J0w== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1726497237; x=1727102037; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=rT7fkfgKvdnxFcCjnHIHT63TtCsP/eoL84gnJAKgmpM=; b=dkDfPWjtBEzWNCw92F0TsdoEnTNBEU73ZUd+YUf4k3IZEKp/VkWs6oF2sCOFUb8S20 5oOazyOo1FdEt+GLiAJuc/pR3fWUvTKmGDWgly/GJyFlw5vLf5SjAgmDstE0pDZ0/0wT 5Wg5JkWNln+apxNHdGL8xmeqOy7zsFA5ayOFaUqtnRhyUn+1OhFHbFzVx5fkw83r/qEH NJW2NQsm0AknHkjeXlODibrOBDVYQpc7gQGK0vprGDEiaTpylPV1RAHMd8kBvFFWlS6R Hz8rNHk3xI7MVrAF2cH3cb1zWQADVVTI1qi4Isly28vH2G9JytJqOLseozg7TCWeOtl9 eQWQ== X-Forwarded-Encrypted: i=1; AJvYcCXVlJLhkBsYcd4uR4VtcdQjS0jON65IiR1osBZ7hDSEOD0FWes3u6NKBSs2zzgB0iB8wgX2B7QYl1sTe6M=@vger.kernel.org X-Gm-Message-State: AOJu0Yx+FgAL/qUhwS4yBnoPrK/4hqEBZqkEsj/VjzzFKPw1ez6rhxyo dgJDYlyHEKb35Lz2Xow86g/3BkgDH8f31v1/Tapwd5V+lf9sTaE71lvm28u+bj0= X-Google-Smtp-Source: AGHT+IHuJLmHDPZa+OPYL0UN8zzw5+L/Um9tpqARkqF7h1gNDPLFk2SH4KGpi8v0RdJu9yZmVO/kwA== X-Received: by 2002:a2e:4e11:0:b0:2f7:4fac:f695 with SMTP id 38308e7fff4ca-2f787dbf6e6mr64543501fa.14.1726497236713; Mon, 16 Sep 2024 07:33:56 -0700 (PDT) Received: from pathway.suse.cz ([193.86.92.181]) by smtp.gmail.com with ESMTPSA id 98e67ed59e1d1-2dbcfd25d21sm5247470a91.33.2024.09.16.07.33.51 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Sep 2024 07:33:56 -0700 (PDT) Date: Mon, 16 Sep 2024 16:33:46 +0200 From: Petr Mladek To: Rik van Riel Cc: John Ogness , Andrew Morton , Omar Sandoval , linux-kernel@vger.kernel.org, Steven Rostedt , Sergey Senozhatsky , kernel-team Subject: Re: [RFC PATCH] nmi,printk: fix ABBA deadlock between nmi_backtrace and dump_stack_lvl Message-ID: References: <20240715232052.73eb7fb1@imladris.surriel.com> <87plrcqyii.fsf@jogness.linutronix.de> <93155b2ccafa43ed4845ae450451c6b8e27509cc.camel@surriel.com> <87r0brkvqd.fsf@jogness.linutronix.de> <877cdilrko.fsf@jogness.linutronix.de> <871q3ix2zp.fsf@jogness.linutronix.de> 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=us-ascii Content-Disposition: inline In-Reply-To: On Fri 2024-09-13 13:25:33, Rik van Riel wrote: > On Wed, 2024-07-24 at 17:08 +0200, Petr Mladek wrote: > > On Wed 2024-07-24 16:51:46, John Ogness wrote: > > > > > > I see. I agree that deferring printk on that CPU [0] is the right > > solution. > > > > > [0] > > > https://lore.kernel.org/lkml/87plrcqyii.fsf@jogness.linutronix.de > > > Hi Petr, > > we have been running with John Ogness's fix (from the mail linked > above) for about a month now, and it has reduced the number of > deadlocks in the Linux kernel in our fleet by maybe 90%, comparing > a kernel with the fix, to a kernel without the fix. > > Would it be possible to get John Ogness's fix queued up for merging > in the printk tree, and then later to Linus? Sure. Thanks for reminder. John, could you please send the fix as a proper patch with some reasonable commit message? Best Regards, Petr