From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-pf1-f175.google.com (mail-pf1-f175.google.com [209.85.210.175]) (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 D5915EA0 for ; Mon, 13 Jun 2022 16:49:06 +0000 (UTC) Received: by mail-pf1-f175.google.com with SMTP id w21so6293887pfc.0 for ; Mon, 13 Jun 2022 09:49:06 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=9ALP8lsGfjdjgEofzfsJxd9qV2mlI2gIpt2uj+q0ckY=; b=czz4osvuz+f2/S9+hKIjWaAk9nwSjJ5BOHALM+L8npDyOhQSu1gub0HzMFya7upev0 ksc11lhUgxu5WOL1X01iW7xW28n2VADA6Drw9tJPihqqX620yo73SEmRJ6hGnGZOAzjq qAUgNs2B0F1W/wZQbVz2t2VLJ5nKXleE2zBa5OitnNb8XSHZrsJFKLMtydUtpznI1+9E fehC7wCZeJMpJkFmbogNuBdjfUA42uqOY4DxjxHRGdQyX1ltUipgYipCxG2mdtoliuRV jlddM/kmMTj75GnveSpGfFLOg8Kf6qr7icepy6U07x7cpPImoEsYWl/QwxdTSCRmlv4P UeiA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=9ALP8lsGfjdjgEofzfsJxd9qV2mlI2gIpt2uj+q0ckY=; b=vTlkdE3/TRKniVRl4BR8nG8tQPamo2F798Hg12YRHRe/JwSIVsNp0Vqan9n7HYRnFC XER+Haa8PdzIr5QeEygqjLZwfuewTHURTehnLFMqoQiiHRMjJt9P03LOuyEaGpd3JoiP uS0UkX62BpEpGoJYtLJR8RS/JIG6q9oaBUB0pevoN4va+ywqAkRGDQMpB7ard5wqm2wv 24ObBKNo4nhGcXeRyF9uSo+U46mLBhENvDkPyb+HFF87Rdzg8FwNWavt3ZOSTPtLhwum TdjIwtjLf0ZOjKlwNGVvRmrBsshrcWzTJ0ztOwm60Aj07pL4YBoGGlWuwAJ/miLOFC0g fUbA== X-Gm-Message-State: AOAM530WC0+5oLI4r0wbERumwnueh4W6fSsjWsLxNkD518S1ZTiDO874 nmyIjzJXhlGW5gn6tC4S+Lo= X-Google-Smtp-Source: ABdhPJz7UaAu1dmwAfduVnLzoXN0rY0S0U8WJE6KWUcTeKiIhK5MLmLXhvJaShL6SyWBuIMPeljjvA== X-Received: by 2002:a05:6a00:3491:b0:51c:1d3b:b0b0 with SMTP id cp17-20020a056a00349100b0051c1d3bb0b0mr131559pfb.68.1655138946195; Mon, 13 Jun 2022 09:49:06 -0700 (PDT) Received: from google.com ([2620:15c:211:201:43cb:e071:e7f2:5e7a]) by smtp.gmail.com with ESMTPSA id ij7-20020a170902ab4700b001621cd83e49sm5356623plb.92.2022.06.13.09.49.04 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 13 Jun 2022 09:49:05 -0700 (PDT) Sender: Minchan Kim Date: Mon, 13 Jun 2022 09:49:03 -0700 From: Minchan Kim To: Sergey Senozhatsky , umgwanakikbuti@gmail.com, bigeasy@linutronix.de Cc: Naresh Kamboju , open list , linux-fsdevel@vger.kernel.org, Linux ARM , "open list:KERNEL SELFTEST FRAMEWORK" , linux-block , regressions@lists.linux.dev, Jens Axboe , Nitin Gupta Subject: Re: qemu-arm: zram: mkfs.ext4 : Unable to handle kernel NULL pointer dereference at virtual address 00000140 Message-ID: References: Precedence: bulk X-Mailing-List: regressions@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: On Mon, Jun 13, 2022 at 04:54:07PM +0900, Sergey Senozhatsky wrote: > Hello, > > On (22/06/12 20:56), Naresh Kamboju wrote: > > > > I have tested this patch and the reported issue got resolved [1]. > > > > Many thanks for the tests. > > Quite honestly I was hoping that the patch would not help :) Well, ok, > we now know that it's mapping area lock and the lockdep part of its > memory is zero-ed out. The question is - "why?" It really should not > be zeroed out. Ccing Mike and Sebastian who are author/expert of the culprit patch Naresh found zsmalloc crashed on the testing [1] and confirmed that Sergey's patch[2] fixed the problem. However, I don't understand why we need reinit the local_lock on cpu_up handler[3]. Could you guys shed some light? [1] https://lore.kernel.org/all/CA+G9fYtVOfWWpx96fa3zzKzBPKiNu1w3FOD4j++G8MOG3Vs0EA@mail.gmail.com/ [2] https://lore.kernel.org/all/YqBRZcsfrRMZXMCC@google.com/ [3] https://lore.kernel.org/all/YqEKapKLBgKEXGBg@google.com/