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]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E0A42FF8868 for ; Tue, 28 Apr 2026 13:09:08 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id 56EDF6B008A; Tue, 28 Apr 2026 09:09:08 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 51DC36B008C; Tue, 28 Apr 2026 09:09:08 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 45BC26B0092; Tue, 28 Apr 2026 09:09:08 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0014.hostedemail.com [216.40.44.14]) by kanga.kvack.org (Postfix) with ESMTP id 3486A6B008A for ; Tue, 28 Apr 2026 09:09:08 -0400 (EDT) Received: from smtpin02.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay06.hostedemail.com (Postfix) with ESMTP id EBC321B7090 for ; Tue, 28 Apr 2026 13:09:07 +0000 (UTC) X-FDA: 84707995134.02.6EDC2AC Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf15.hostedemail.com (Postfix) with ESMTP id 31AC0A0019 for ; Tue, 28 Apr 2026 13:09:05 +0000 (UTC) Authentication-Results: imf15.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=e4JN5naQ; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf15.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1777381746; 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=4nqivCc2PRJMXKSuCzKBaD7+S/jHJk0M6k+CUV6NswQ=; b=4DXSyFqUvQdkdeQqdR189IyBBXXwGf9nRoyUAdP1NoFUp2MMZMZFv+mlmAq3HrC6ZeW9O1 tPhp2NI/wzjFMBFrH8a3N1lbttsIZ2+6A0Pn9jx3mpjru0IbeVDPG5yrP9mVLZ8l8C2LZp MU0dmja0wjm4+Z6YDB9VdXetDkbSIfM= ARC-Seal: i=1; s=arc-20220608; d=hostedemail.com; t=1777381746; a=rsa-sha256; cv=none; b=H61WEStymC4mMrYKQSmmhF5JCDpxCGUutY+uTnA77AFzZgodFZ7xgMYVLUi1zx+KTiwMVb n5kXA6NDfNB4AkYrK5Mfg1yfJ2rmAoZRglx1LYcDKG5K0IHaPQQtaIfvB3afUtW+cOlnj3 BVpF7E6DKWY/owDFRZcoFNnjBF3M/D4= ARC-Authentication-Results: i=1; imf15.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20201202 header.b=e4JN5naQ; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf15.hostedemail.com: domain of rppt@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=rppt@kernel.org Received: from smtp.kernel.org (transwarp.subspace.kernel.org [100.75.92.58]) by tor.source.kernel.org (Postfix) with ESMTP id 6AEB861119; Tue, 28 Apr 2026 13:09:05 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 74F66C2BCAF; Tue, 28 Apr 2026 13:08:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1777381745; bh=y5Wj2Mshp/u7h62ACdtB57U1YInb0w7gkuhwEVUSYGA=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=e4JN5naQJ+TlVk6mBeIiP5kBgPhrbIsfSTf/vPhjQnRELi7dpfbVtB7ACoelq3Jap 1zY46otM4NN1WLpNBlVPTdA1TzJh35tO9otOfRJTFL5s+h3VbR7VadwmoPQCR6XGDP NgYZ1g8KA7kTtq1YHu3G1h0OjgQTnJnYjtx3FVNrvmuSvvNrcGXPeZQoBB292gh4Ie hxyYVQSqY8X2a4YFRViC2EZb1IZyWUPFLf44FM8zPleXw3gUUQQ0msO05RFejgRbgY 9F6sK+FnOIcDgn5tr9dN6HAJhet4K1gOT/1BuGP0IGaTdVie8lwjqKQv4pqVuwZ/gB l29nT7E3K7OXQ== Date: Tue, 28 Apr 2026 15:08:55 +0200 From: Mike Rapoport To: Muchun Song 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 Subject: Re: [PATCH 09/49] mm: panic on memory allocation failure in sparse_init_nid() Message-ID: References: <20260405125240.2558577-1-songmuchun@bytedance.com> <20260405125240.2558577-10-songmuchun@bytedance.com> <9FD13495-58E8-4183-AAC0-48E50A694ADE@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <9FD13495-58E8-4183-AAC0-48E50A694ADE@linux.dev> X-Rspamd-Server: rspam03 X-Rspamd-Queue-Id: 31AC0A0019 X-Stat-Signature: 513b987ijym88q553xjckxqb1ywmya9g X-Rspam-User: X-HE-Tag: 1777381745-883946 X-HE-Meta: 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 MnH1kE+L YE2eYFEdtzpBN1iPTdbaIfipuWw5s7zondzQBp5acfhuMchKDhaGIiz2jvlhevJWUwdmxheW7Pn6DrpuqlpIgc71e02JCN7sGJWrmoQK8m+FzTH3SbcXdjGu1xm/MbglXXWjuTk73a1ab7lA15Tn6RXsEDpSiHdAjQJBnQBuWAghCK+XjXwbjrGHVTeTwuYR9migtSKj6L5AQC4+4LZu1EcnTgPfhkqviEw/fxDMFVBF8lpf0lnOKpqc2F4WVH4oTj2jAZe76sSLfsaYjrNdR6Di38+oOCSuoMp3xz3Aj9+nn2Nnjv4RdWbohaAtVzZt0yI+yOedLO4w4oUKAr7LIksdoWYJ4lCiNfkAa Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Hi Muchun, On Tue, Apr 28, 2026 at 08:13:05PM +0800, Muchun Song wrote: > > > On Apr 28, 2026, at 14:56, Mike Rapoport wrote: > > > > 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). > >> > >> 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. > >> > >> Therefore, use BUG_ON() to panic immediately if allocation fails, instead of > >> attempting a partial recovery that leads to obscure crashes later. > >> > >> Signed-off-by: Muchun Song > > > > Acked-by: Mike Rapoport (Microsoft) > > > >> --- > >> mm/sparse.c | 37 ++++++++----------------------------- > >> 1 file changed, 8 insertions(+), 29 deletions(-) > >> > >> 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; > >> - } > >> > >> + if (sparse_usage_init(nid, map_count)) > >> + panic("The node[%d] usemap allocation failed\n", nid); > > > > 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. Heh, I missed the nid part :) There are a few _node_ or _nid_ allocation helpers in memblock, starting to add _nopanic for them would be overkill. Let's keep panic()s at call sites. > Thanks. > > -- Sincerely yours, Mike.