From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id EF605C433EF for ; Thu, 9 Jun 2022 12:32:20 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244663AbiFIMcT (ORCPT ); Thu, 9 Jun 2022 08:32:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47004 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237961AbiFIMcP (ORCPT ); Thu, 9 Jun 2022 08:32:15 -0400 Received: from mail-lf1-x129.google.com (mail-lf1-x129.google.com [IPv6:2a00:1450:4864:20::129]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7522118353 for ; Thu, 9 Jun 2022 05:32:13 -0700 (PDT) Received: by mail-lf1-x129.google.com with SMTP id h23so37753660lfe.4 for ; Thu, 09 Jun 2022 05:32:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=SfBdadjjVbuYsWcHjyT2JNkeKnRXZofpQUc3M0v3lw8=; b=ZuexHRJpNkArhkzlyVFzZzfvSGVG0EYbj1SnK7hExFfijK7WjsRYWBLE0IAgfsl2Zi MEyYD78r42eLMgaGkHPJR1S3gTnNwQnEllIN+QBILQnNTymZq4f19Yu/6jG5M503bWVv sTnn/1fbYfOfY6pb0CbXuakmf+f9jM1TKXottjCpAfvvenicMckun+zADDhluMOtEFEr Fltda09pvIbbAqK5WXQ/PojELjI4dNLYnujpwmEs+PosBQICQSiY48ZEGW61ag+09nDR naerd/Vk9Iwjla68zxr0uqMt7jTerwywgXFZ3UjNXRbXyEQGZgLfPS9674SbORQU4h6m PWww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=SfBdadjjVbuYsWcHjyT2JNkeKnRXZofpQUc3M0v3lw8=; b=Il26Rr0jriFE7IGnTdmZvmvlbRQXwNRkAYyT2LOu/oGOgYvkWQ4iz+FQR1i2mq0aFw 5C7VQ0eq/m0TjJds5ATYAYEOgVS3ZMs9/u7Rj/DKYLxjb7hTl1sRMxINQHyzjHSt7ynq IzFs/i8uPp8iWWxPFqw0/ZDcBDIthQnqToU1VDQLDFPqrwnfiLOHsTKPQ82ip5Cj+wMY Nz5hq9nWCcbuhkvfFRuSDCS8MRL26XkRAtMr26sGEiCjdxaQOwUo95iuvzJdbwf6a9ia p9oWuEhCjM9KXU20e47b3ofJx2qFpetKpw2MerxnRHEGif+1VrC1/NTUscmf0oI2xsIt dKEw== X-Gm-Message-State: AOAM532bnxEMcPtNhtmW5efJaNS2iPFaNPTnxv0b1Up5yqLRVyfrR5cl +23Ji83RZwQ9HmZb1fY5rKO8/wSwxA6SZTV1T4/LSA== X-Google-Smtp-Source: ABdhPJzLWjIsu++QNIx3qDCOGVcwgjQAzeuOsueKw0KOpXNjxn2Gz9hA0HmKib9smkmGcaOLoJgCB0QQYNMhpqx7BYk= X-Received: by 2002:a05:6512:1588:b0:477:a556:4ab2 with SMTP id bp8-20020a056512158800b00477a5564ab2mr24638097lfb.376.1654777931483; Thu, 09 Jun 2022 05:32:11 -0700 (PDT) MIME-Version: 1.0 References: <87fslyv6y3.fsf@jogness.linutronix.de> <51dfc4a0-f6cf-092f-109f-a04eeb240655@samsung.com> <87k0b6blz2.fsf@jogness.linutronix.de> <32bba8f8-dec7-78aa-f2e5-f62928412eda@samsung.com> <87y1zkkrjy.fsf@jogness.linutronix.de> <87fske3wzw.fsf@jogness.linutronix.de> In-Reply-To: From: Dmitry Vyukov Date: Thu, 9 Jun 2022 14:32:00 +0200 Message-ID: Subject: Re: [PATCH printk v5 1/1] printk: extend console_lock for per-console locking To: "Jason A. Donenfeld" Cc: John Ogness , Geert Uytterhoeven , Marek Szyprowski , Petr Mladek , Sergey Senozhatsky , Steven Rostedt , Thomas Gleixner , Linux Kernel Mailing List , Greg Kroah-Hartman , "open list:ARM/Amlogic Meson..." , "Theodore Ts'o" , Alexander Potapenko , Marco Elver , kasan-dev@googlegroups.com, bigeasy@linutronix.de Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 9 Jun 2022 at 14:27, Jason A. Donenfeld wrote: > > Hi Dmitry, > > On Thu, Jun 09, 2022 at 02:18:19PM +0200, Dmitry Vyukov wrote: > > > AFAIK, CONFIG_PROVE_RAW_LOCK_NESTING is useful for teasing out cases > > > where RT's raw spinlocks will nest wrong with RT's sleeping spinlocks. > > > But nobody who wants an RT kernel will be using KFENCE. So this seems > > > like a non-issue? Maybe just add a `depends on !KFENCE` to > > > PROVE_RAW_LOCK_NESTING? > > > > Don't know if there are other good solutions (of similar simplicity). > > Fortunately, I found one that solves things without needing to > compromise on anything: > https://lore.kernel.org/lkml/20220609121709.12939-1-Jason@zx2c4.com/ Cool! Thanks! > > Btw, should this new CONFIG_PROVE_RAW_LOCK_NESTING be generally > > enabled on testing systems? We don't have it enabled on syzbot. > > Last time I spoke with RT people about this, the goal was eventually to > *always* enable it when lock proving is enabled, but there are too many > bugs and cases now to do that, so it's an opt-in. I might be > misremembering, though, so CC'ing Sebastian in case he wants to chime > in. OK, we will wait then. Little point in doubling the number of reports for known issues. From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 3C6EAC433EF for ; Thu, 9 Jun 2022 12:32:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender: Content-Transfer-Encoding:Content-Type:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:Cc:To:Subject:Message-ID:Date:From: In-Reply-To:References:MIME-Version:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=WWQd6xFd+mRLc3RgLkRXL78SvGyzgpen3/P8zdy8Dug=; b=boyWizmePeZeel kt5iy/N387Og7x8qfT/eQjAPORYVakZbCQK9pXK/U8veDVHpUGUquPqM8SrqcPNterVXCf0pt3F5Z UDbRqaLR5nOZdGB+OI+t2+k4MTBN6o20ghaD1T9hUials299/rMr7uQ6gEksHPkCJf0LWvTi2SBx9 77TAeEwCUHeKMjt7E+H1dosGpkE9hvoErP9Vk6eJUVtxemcDYJuXYFYEiQrYwB/4CNlgnBy0/xFzw gft4WFOY0/VK7H+D3Y/icwaZEcuOzSmdo9sLKxotP+Qn0s+8MIDxR6sJHicDquh/ceNTtaxj1a66e 94R8SNO1F2hobec949/g==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.94.2 #2 (Red Hat Linux)) id 1nzHKl-001mZB-KP; Thu, 09 Jun 2022 12:32:19 +0000 Received: from mail-lf1-x12e.google.com ([2a00:1450:4864:20::12e]) by bombadil.infradead.org with esmtps (Exim 4.94.2 #2 (Red Hat Linux)) id 1nzHKi-001mWn-8g for linux-amlogic@lists.infradead.org; Thu, 09 Jun 2022 12:32:17 +0000 Received: by mail-lf1-x12e.google.com with SMTP id a29so9242642lfk.2 for ; Thu, 09 Jun 2022 05:32:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=SfBdadjjVbuYsWcHjyT2JNkeKnRXZofpQUc3M0v3lw8=; b=ZuexHRJpNkArhkzlyVFzZzfvSGVG0EYbj1SnK7hExFfijK7WjsRYWBLE0IAgfsl2Zi MEyYD78r42eLMgaGkHPJR1S3gTnNwQnEllIN+QBILQnNTymZq4f19Yu/6jG5M503bWVv sTnn/1fbYfOfY6pb0CbXuakmf+f9jM1TKXottjCpAfvvenicMckun+zADDhluMOtEFEr Fltda09pvIbbAqK5WXQ/PojELjI4dNLYnujpwmEs+PosBQICQSiY48ZEGW61ag+09nDR naerd/Vk9Iwjla68zxr0uqMt7jTerwywgXFZ3UjNXRbXyEQGZgLfPS9674SbORQU4h6m PWww== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=SfBdadjjVbuYsWcHjyT2JNkeKnRXZofpQUc3M0v3lw8=; b=1R2It0m8d47Xzx9oXYST17wSe+DLZl//tUgYguWPGcVyqfvNrvtKmIMWE7AndbDz+A dLo9d87gcr0Iqqy20JoVoklCaXbGDxGhaOoRs3MTZgKPHvZQg4FSFAEOyv5n3NOmieBO WIjrDX+lFjRce/jnzQK3LoHahQw0aHALna/vxMksQjRWXVWl0l0vZinMlOhtAj+PJeT/ 4HMT5NDFaEc14GZO2A7ZK+VvmxeUDxGGFyA4zZBGxENJqTr9H/Wkw7CqUEx6FLqPrrsf loPI4v5FeOAGp8NibSCgQojR4mCGBM+TTQUkUxDnPFeOH5bErdqUqLvqkRO4U+pZSQdG EF1Q== X-Gm-Message-State: AOAM530E2i2B77fRmpFicakyhtf7XoAO8ZTJOAocAqE9jysarzpEIZiM GiK5fekeMnSlF62YkN//6lxmqbXTIUTw+70TFgHBVQ== X-Google-Smtp-Source: ABdhPJzLWjIsu++QNIx3qDCOGVcwgjQAzeuOsueKw0KOpXNjxn2Gz9hA0HmKib9smkmGcaOLoJgCB0QQYNMhpqx7BYk= X-Received: by 2002:a05:6512:1588:b0:477:a556:4ab2 with SMTP id bp8-20020a056512158800b00477a5564ab2mr24638097lfb.376.1654777931483; Thu, 09 Jun 2022 05:32:11 -0700 (PDT) MIME-Version: 1.0 References: <87fslyv6y3.fsf@jogness.linutronix.de> <51dfc4a0-f6cf-092f-109f-a04eeb240655@samsung.com> <87k0b6blz2.fsf@jogness.linutronix.de> <32bba8f8-dec7-78aa-f2e5-f62928412eda@samsung.com> <87y1zkkrjy.fsf@jogness.linutronix.de> <87fske3wzw.fsf@jogness.linutronix.de> In-Reply-To: From: Dmitry Vyukov Date: Thu, 9 Jun 2022 14:32:00 +0200 Message-ID: Subject: Re: [PATCH printk v5 1/1] printk: extend console_lock for per-console locking To: "Jason A. Donenfeld" Cc: John Ogness , Geert Uytterhoeven , Marek Szyprowski , Petr Mladek , Sergey Senozhatsky , Steven Rostedt , Thomas Gleixner , Linux Kernel Mailing List , Greg Kroah-Hartman , "open list:ARM/Amlogic Meson..." , "Theodore Ts'o" , Alexander Potapenko , Marco Elver , kasan-dev@googlegroups.com, bigeasy@linutronix.de X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20220609_053216_379265_1BEBA1E2 X-CRM114-Status: GOOD ( 18.93 ) X-BeenThere: linux-amlogic@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-amlogic" Errors-To: linux-amlogic-bounces+linux-amlogic=archiver.kernel.org@lists.infradead.org On Thu, 9 Jun 2022 at 14:27, Jason A. Donenfeld wrote: > > Hi Dmitry, > > On Thu, Jun 09, 2022 at 02:18:19PM +0200, Dmitry Vyukov wrote: > > > AFAIK, CONFIG_PROVE_RAW_LOCK_NESTING is useful for teasing out cases > > > where RT's raw spinlocks will nest wrong with RT's sleeping spinlocks. > > > But nobody who wants an RT kernel will be using KFENCE. So this seems > > > like a non-issue? Maybe just add a `depends on !KFENCE` to > > > PROVE_RAW_LOCK_NESTING? > > > > Don't know if there are other good solutions (of similar simplicity). > > Fortunately, I found one that solves things without needing to > compromise on anything: > https://lore.kernel.org/lkml/20220609121709.12939-1-Jason@zx2c4.com/ Cool! Thanks! > > Btw, should this new CONFIG_PROVE_RAW_LOCK_NESTING be generally > > enabled on testing systems? We don't have it enabled on syzbot. > > Last time I spoke with RT people about this, the goal was eventually to > *always* enable it when lock proving is enabled, but there are too many > bugs and cases now to do that, so it's an opt-in. I might be > misremembering, though, so CC'ing Sebastian in case he wants to chime > in. OK, we will wait then. Little point in doubling the number of reports for known issues. _______________________________________________ linux-amlogic mailing list linux-amlogic@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-amlogic