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 X-Spam-Level: X-Spam-Status: No, score=-14.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 23E5DC433E0 for ; Wed, 3 Feb 2021 01:32:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DB5DA64F4C for ; Wed, 3 Feb 2021 01:32:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231136AbhBCBb7 (ORCPT ); Tue, 2 Feb 2021 20:31:59 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57498 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231147AbhBCBbs (ORCPT ); Tue, 2 Feb 2021 20:31:48 -0500 Received: from mail-pg1-x530.google.com (mail-pg1-x530.google.com [IPv6:2607:f8b0:4864:20::530]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2BABEC0613ED; Tue, 2 Feb 2021 17:31:08 -0800 (PST) Received: by mail-pg1-x530.google.com with SMTP id o16so16165967pgg.5; Tue, 02 Feb 2021 17:31:08 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:in-reply-to; bh=T+IFulWS30TVdfKg6FbK/0wljc+JOjEQqde/nrXKzCI=; b=pHh0nOo43ZTL5LL9P7k8jk/hC0amgWajB0mH3Dxb+vwAmJsJmm/nGyaG++L/G1mVNK eDiW55ib9GCrzzm1FaVcoNxYgnApFS7wl0oXCt4dHRtUunxsYGX4PyyZG9peXq3jNugE 9jqld7I4QdoQTqMGI1xnvPCO6XSRkm/HRq/sXHP0RHvxaC3GeBTRLlvfHUqCOrgjhPjI 7sZ6na77hAuh5dI+E6MUQnVguhNOdS2AzUAGlmPiqSKzcXP09y9xoGCXVukyBxOtWZxt u2Ki9FNu/+eDKY60VVxREEQkIKo3xthogr7K0IvOl5r8kHX9pJfkJkvG/XcYHqU8fKY4 EvmQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition:in-reply-to; bh=T+IFulWS30TVdfKg6FbK/0wljc+JOjEQqde/nrXKzCI=; b=eE0sVSqa/gXfP/9j1nFPOFzdHGTiz0rDgd37z4n94fTYUTeQO/D+sUGRcFodwfG62f jZ1ErS8RLW2EHqh0HQ3O0rX22ucLhNWaPFA2kl2PcO5qaWipJ/ikqnQe2Xs11rLzNczT MSpqa4h+5Eqr87hGhjTsdW+cnYaOeBGQSo6h/SYmWdYaO/3p58wl11AHVochlTV1hv8c CnSAD7zibysBZcfocBFFXFDRDrV+nx/45wNdr8SdmV9DFM/3Vds32mYAOO7z/745eAdG oJnsfC9lqvAfDF/v7KEGPKH35albbfXYD6U+3SZvSOyb9uTigIp3Ebe35HDfHMNp5BDk VIuA== X-Gm-Message-State: AOAM533aw1u1HxZx7IqjAg2owybg4RETON6QqcNeRh5MMlb9ZTbK2sIx vQFH/AOkq0XpEKNyWYFYoD0= X-Google-Smtp-Source: ABdhPJz+SHeDGDiOTFr7BCLmdLVZac+uhes3CUQ3tgyGdAX3UbuwtARrizczD0kVVmAQ9gNAoPNKtA== X-Received: by 2002:a62:f202:0:b029:1bc:a634:8e9c with SMTP id m2-20020a62f2020000b02901bca6348e9cmr717628pfh.49.1612315867684; Tue, 02 Feb 2021 17:31:07 -0800 (PST) Received: from google.com ([2620:15c:211:201:1502:84f8:ffc3:45b]) by smtp.gmail.com with ESMTPSA id o20sm212189pgn.6.2021.02.02.17.31.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 02 Feb 2021 17:31:06 -0800 (PST) Sender: Minchan Kim Date: Tue, 2 Feb 2021 17:31:03 -0800 From: Minchan Kim To: Suren Baghdasaryan Cc: sumit.semwal@linaro.org, akpm@linux-foundation.org, hch@infradead.org, lmark@codeaurora.org, labbott@redhat.com, Brian.Starkey@arm.com, john.stultz@linaro.org, christian.koenig@amd.com, cgoldswo@codeaurora.org, orjan.eide@arm.com, robin.murphy@arm.com, jajones@nvidia.com, hridya@google.com, sspatil@google.com, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kernel-team@android.com Subject: Re: [PATCH 1/2] mm: replace BUG_ON in vm_insert_page with a return of an error Message-ID: References: <20210203003134.2422308-1-surenb@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210203003134.2422308-1-surenb@google.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Feb 02, 2021 at 04:31:33PM -0800, Suren Baghdasaryan wrote: > Replace BUG_ON(vma->vm_flags & VM_PFNMAP) in vm_insert_page with > WARN_ON_ONCE and returning an error. This is to ensure users of the > vm_insert_page that set VM_PFNMAP are notified of the wrong flag usage > and get an indication of an error without panicing the kernel. > This will help identifying drivers that need to clear VM_PFNMAP before > using dmabuf system heap which is moving to use vm_insert_page. > > Suggested-by: Christoph Hellwig > Signed-off-by: Suren Baghdasaryan > --- > mm/memory.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/memory.c b/mm/memory.c > index feff48e1465a..e503c9801cd9 100644 > --- a/mm/memory.c > +++ b/mm/memory.c > @@ -1827,7 +1827,8 @@ int vm_insert_page(struct vm_area_struct *vma, unsigned long addr, > return -EINVAL; > if (!(vma->vm_flags & VM_MIXEDMAP)) { > BUG_ON(mmap_read_trylock(vma->vm_mm)); Better to replace above BUG_ON with WARN_ON_ONCE, too?