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 lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (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 E7C01FF885D for ; Tue, 28 Apr 2026 12:14:16 +0000 (UTC) Received: from boromir.ozlabs.org (localhost [127.0.0.1]) by lists.ozlabs.org (Postfix) with ESMTP id 4g4fVv1XTHz2xlt; Tue, 28 Apr 2026 22:14:15 +1000 (AEST) Authentication-Results: lists.ozlabs.org; arc=none smtp.remote-ip=95.215.58.176 ARC-Seal: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1777378455; cv=none; b=QryRQYJ2Plhq04drFpJMm9VPLv11FM15m+jIpBFgWhBkfssUl7MKZzIrdtTAbYyirlCKdSmMV25FWj5o085mv3B+mjSev1z/xto7H6CFqKmh+1O5xn7szX3urDCPC/rxPk9V1BIBTn+17yCspEYzLv7FLeHHiIasX20A5ITA5Z0cjinXDaP4AeV+5v64x/sR4Z/0JUrT1mf/fgXZrKSyvZAZTBAg0LQQapTCRYx6ekNrC7a7kFbFeqiIdBkmiAQFrurDNXQ0RUp2qybRGXAfnPCIFyN/eH4hC/E2itxtKbkeHdhtsMNvaElL/qZKOaKrjLdKmnP2LTXIQE4R0kJekw== ARC-Message-Signature: i=1; a=rsa-sha256; d=lists.ozlabs.org; s=201707; t=1777378455; c=relaxed/relaxed; bh=gMW0yphc9+JTsHgjuPXzpOHRe/+uClvfXBtsydm1QXs=; h=Content-Type:Mime-Version:Subject:From:In-Reply-To:Date:Cc: Message-Id:References:To; b=Hp7XwR7d22qfraJAB2Pjqu0n7NQfHE8FKKD9bIONvt3GfzPZqmq0oZBlSn7ppKFYy647N9t69wLsXWsxK/9vdAR450ROO5Ze52VVBDblL7JEwi/aXnsdkLUeMHXQzyoygPBIcYh5P9LgDRcMhm00CnLV8hy8S4496xuKsSrSjb+zFptZJU0050jhUow9OS2pa5MUqXLdt4y4jIs7BC/akYc0LGa3FU/cMN1KZePcmAr7/Eb1qC82mLi52Rgi4dZT5X7+FEAgkoHlVUGuArC5tpUS5UrXAs+0HeBu8GaZm02oGyHQK4gubeSkcowfE04jJIbrpcuv6hMyHcuiTewfVA== ARC-Authentication-Results: i=1; lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=linux.dev; dkim=pass (1024-bit key; unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=liGzZ/6l; dkim-atps=neutral; spf=pass (client-ip=95.215.58.176; helo=out-176.mta1.migadu.com; envelope-from=muchun.song@linux.dev; receiver=lists.ozlabs.org) smtp.mailfrom=linux.dev Authentication-Results: lists.ozlabs.org; dmarc=pass (p=none dis=none) header.from=linux.dev Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=linux.dev header.i=@linux.dev header.a=rsa-sha256 header.s=key1 header.b=liGzZ/6l; dkim-atps=neutral Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=linux.dev (client-ip=95.215.58.176; helo=out-176.mta1.migadu.com; envelope-from=muchun.song@linux.dev; receiver=lists.ozlabs.org) Received: from out-176.mta1.migadu.com (out-176.mta1.migadu.com [95.215.58.176]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange x25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4g4fVr0sj5z2xYw for ; Tue, 28 Apr 2026 22:14:10 +1000 (AEST) Content-Type: text/plain; charset=us-ascii DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1777378430; h=from:from: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:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=gMW0yphc9+JTsHgjuPXzpOHRe/+uClvfXBtsydm1QXs=; b=liGzZ/6lcet38vVzKBuQrY39X3mLjaXryapTkWCkNSiDT8ppz7dunF9bMsRawPXG5pxkR5 FhcWht8cZvdRPdpyR1p4MmEuMLHcB8c/dHAcKROxBElmkdgDF2smPjKbTZo6pmhUkCtZar glo2vu8yjY+mQkvZGqqftuaAu0NP3vQ= X-Mailing-List: linuxppc-dev@lists.ozlabs.org List-Id: List-Help: List-Owner: List-Post: List-Archive: , List-Subscribe: , , List-Unsubscribe: Precedence: list Mime-Version: 1.0 (Mac OS X Mail 16.0 \(3864.500.181\)) Subject: Re: [PATCH 09/49] mm: panic on memory allocation failure in sparse_init_nid() X-Report-Abuse: Please report any abuse attempt to abuse@migadu.com and include these headers. From: Muchun Song In-Reply-To: Date: Tue, 28 Apr 2026 20:13:05 +0800 Cc: Muchun Song , Andrew Morton , David Hildenbrand , Oscar Salvador , Michael Ellerman , Madhavan Srinivasan , Lorenzo Stoakes , "Liam R . Howlett" , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Nicholas Piggin , Christophe Leroy , aneesh.kumar@linux.ibm.com, joao.m.martins@oracle.com, linux-mm@kvack.org, linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: <9FD13495-58E8-4183-AAC0-48E50A694ADE@linux.dev> References: <20260405125240.2558577-1-songmuchun@bytedance.com> <20260405125240.2558577-10-songmuchun@bytedance.com> To: Mike Rapoport X-Migadu-Flow: FLOW_OUT > On Apr 28, 2026, at 14:56, Mike Rapoport wrote: >=20 > On Sun, Apr 05, 2026 at 08:52:00PM +0800, Muchun Song wrote: >> When vmemmap pages allocation or usemap allocation fails, = sparse_init_nid() >> currently only marks the corresponding section as non-present. = However, >> subsequent code like memmap_init() iterating over PFNs does not check = for >> non-present sections, leading to invalid memory access (additional, >> subsection_map_init() accessing the unallocated usemap as well). >>=20 >> It is complex to audit and fix all boot-time PFN iterators to handle = these >> partially initialized sections correctly. Since vmemmap and usemap = allocation >> failures are extremely rare during early boot, the more appropriate = approach >> is to expose the problem as early as possible. >>=20 >> Therefore, use BUG_ON() to panic immediately if allocation fails, = instead of >> attempting a partial recovery that leads to obscure crashes later. >>=20 >> Signed-off-by: Muchun Song >=20 > Acked-by: Mike Rapoport (Microsoft) >=20 >> --- >> mm/sparse.c | 37 ++++++++----------------------------- >> 1 file changed, 8 insertions(+), 29 deletions(-) >>=20 >> diff --git a/mm/sparse.c b/mm/sparse.c >> index effdac6b0ab1..5c12b979a618 100644 >> --- a/mm/sparse.c >> +++ b/mm/sparse.c >> @@ -354,19 +354,15 @@ static void __init sparse_init_nid(int nid, = unsigned long pnum_begin, >> unsigned long map_count) >> { >> unsigned long pnum; >> - struct page *map; >> - struct mem_section *ms; >> - >> - if (sparse_usage_init(nid, map_count)) { >> - pr_err("%s: node[%d] usemap allocation failed", = __func__, nid); >> - goto failed; >> - } >>=20 >> + if (sparse_usage_init(nid, map_count)) >> + panic("The node[%d] usemap allocation failed\n", nid); >=20 > Please consider using memblock_alloc_or_panic() in = sparse_usage_init(), it > would simplify the code even more. Hi Mike, Should we add a new function like memblock_alloc_node_or_panic? Because we want to allocate vmemmap pages on the same node. Thanks.