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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by smtp.lore.kernel.org (Postfix) with ESMTP id 54710C4332F for ; Thu, 24 Nov 2022 04:25:28 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 809176B0071; Wed, 23 Nov 2022 23:25:27 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 790E36B0072; Wed, 23 Nov 2022 23:25:27 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 631816B0074; Wed, 23 Nov 2022 23:25:27 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0011.hostedemail.com [216.40.44.11]) by kanga.kvack.org (Postfix) with ESMTP id 514B56B0071 for ; Wed, 23 Nov 2022 23:25:27 -0500 (EST) Received: from smtpin14.hostedemail.com (a10.router.float.18 [10.200.18.1]) by unirelay07.hostedemail.com (Postfix) with ESMTP id 2A14A1610EC for ; Thu, 24 Nov 2022 04:25:27 +0000 (UTC) X-FDA: 80167046694.14.E163F09 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf26.hostedemail.com (Postfix) with ESMTP id A8CB4140005 for ; Thu, 24 Nov 2022 04:25:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=ARI/pAXuozIsa/5PtEK9I/KIIipzW+PxI1+kaLb328A=; b=H5CAv9Z+wnZ7BI/YJrxryjfUU7 7QsrwnB7u9Q6yO4cSgpIr+fDqGaQucxq518AmWN4Bf6uFMS6itdqHHNgE/swvOg9WSPFmE2K+Ea8V VAXznQ20BSkS2GlGDhp3rhvvJOdUyUmwiBr4VnfOQzPdO4GXaOyLcFOgJseW+vO5K/601WEHOowKM b9UNOzc5DNCcolnwEzH397znXt+WPDDtEAa2URoA/hFfNyml03dQQyKwRcjkuRsolhSFae5Okx6oF PjJDdhCfUG4oFz+yAj0+DGS6RhB9ey4myZqe3GEJCJ+GrLUKdcvMeyf0Q2QMuz03gpJwICR9OSlPJ YPZ7Gc5g==; Received: from willy by casper.infradead.org with local (Exim 4.94.2 #2 (Red Hat Linux)) id 1oy3nh-008NCq-Ea; Thu, 24 Nov 2022 04:25:25 +0000 Date: Thu, 24 Nov 2022 04:25:25 +0000 From: Matthew Wilcox To: Jiasheng Jiang Cc: akpm@linux-foundation.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm/vmalloc: Add check for KMEM_CACHE Message-ID: References: <20221124040226.17953-1-jiasheng@iscas.ac.cn> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20221124040226.17953-1-jiasheng@iscas.ac.cn> ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1669263926; a=rsa-sha256; cv=none; b=hard+WFhb5gIXq82JJ9v4NOUKHkUNXptd1saxe+W2H+2rYuml1VRk4MZgyCNR0XYFZFzPk qcuQoBl3f1Sza4hWkXfXqGi//SvtKy0h9XwXXYd1IzJe3qbP/ltzQ2sBPydC5gi0pll+BR eieDu/nm5tTwsZEma7iZxVUI7tzMdBg= ARC-Authentication-Results: i=1; imf26.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=H5CAv9Z+; spf=none (imf26.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1669263926; h=from:from:sender:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type:content-transfer-encoding: in-reply-to:in-reply-to:references:references:dkim-signature; bh=ARI/pAXuozIsa/5PtEK9I/KIIipzW+PxI1+kaLb328A=; b=vAMOX0fRKKwJNQlyR2AhxPUMpmldMqQQXd3TnY/9j2RP0gbfsiZ7aiG1GDLn+FkKntVvF5 Yn0TM95XPz0VlmIDokJ3O3dZHCSSKwb+A63V0mhmKSsOj6G++4b0HopyLuOI4NfxHLfe1O WauYFzlJXFSFO3dDkbnjyNnxDiHmGsU= X-Stat-Signature: gz1f416h1infx81tsfoim8m39neeuwrz X-Rspamd-Queue-Id: A8CB4140005 X-Rspam-User: Authentication-Results: imf26.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=H5CAv9Z+; spf=none (imf26.hostedemail.com: domain of willy@infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=willy@infradead.org; dmarc=none X-Rspamd-Server: rspam02 X-HE-Tag: 1669263925-845089 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: On Thu, Nov 24, 2022 at 12:02:26PM +0800, Jiasheng Jiang wrote: > As KMEM_CACHE may return NULL pointer, it should > be better to check the return value in order to > avoid NULL pointer dereference in kmem_cache_zalloc. You've made the code more complex. And for what? If that call fails, the system will not boot under any circumstances. NAK this patch, and any more like it. > Fixes: 68ad4a330433 ("mm/vmalloc.c: keep track of free blocks for vmap allocation") > Signed-off-by: Jiasheng Jiang > --- > mm/vmalloc.c | 18 ++++++++++-------- > 1 file changed, 10 insertions(+), 8 deletions(-) > > diff --git a/mm/vmalloc.c b/mm/vmalloc.c > index ccaa461998f3..df3e59f614cc 100644 > --- a/mm/vmalloc.c > +++ b/mm/vmalloc.c > @@ -2426,15 +2426,17 @@ void __init vmalloc_init(void) > } > > /* Import existing vmlist entries. */ > - for (tmp = vmlist; tmp; tmp = tmp->next) { > - va = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT); > - if (WARN_ON_ONCE(!va)) > - continue; > + if (!WARN_ON_ONCE(!vmap_area_cachep)) { > + for (tmp = vmlist; tmp; tmp = tmp->next) { > + va = kmem_cache_zalloc(vmap_area_cachep, GFP_NOWAIT); > + if (WARN_ON_ONCE(!va)) > + continue; > > - va->va_start = (unsigned long)tmp->addr; > - va->va_end = va->va_start + tmp->size; > - va->vm = tmp; > - insert_vmap_area(va, &vmap_area_root, &vmap_area_list); > + va->va_start = (unsigned long)tmp->addr; > + va->va_end = va->va_start + tmp->size; > + va->vm = tmp; > + insert_vmap_area(va, &vmap_area_root, &vmap_area_list); > + } > } > > /* > -- > 2.25.1 > >