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[109.81.90.161]) by smtp.gmail.com with ESMTPSA id 5b1f17b1804b1-490bc3cc140sm447585645e9.9.2026.06.08.01.02.26 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 08 Jun 2026 01:02:26 -0700 (PDT) Date: Mon, 8 Jun 2026 10:02:25 +0200 From: Michal Hocko To: Ruoyu Wang Cc: Johannes Weiner , Roman Gushchin , Shakeel Butt , Muchun Song , Andrew Morton , cgroups@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] mm: memcontrol-v1: use nofail allocations for soft limit trees Message-ID: References: <20260608063644.39-1-ruoyuw560@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260608063644.39-1-ruoyuw560@gmail.com> X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: D082240004 X-Stat-Signature: 985w55jnr4ftw9fq1xg4ydwsmoi9bojz X-Rspam-User: X-HE-Tag: 1780905748-595045 X-HE-Meta: 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 5cDpOb3B +K33KOt7usivTud5HAAk9/xwcYZIvMs16o9P7/ZuAjI7cbvUO1oPhurhoKuHZqDBlc1ST36pGCKbM2l6S8Bv3yGcVt6BgBzNz7V/exOphALwhk/Wn/4CYYH/X/sm07WlscC+XwrI5DHsY7msT361gS3PYoFLoghJRnxBj8J9g76DEMBDSja1ktOYUHnrevIpfb7OZMHu5N+EhQu0n2DXD9pGE6/ltIcvb1w6/Eek/BBwqFqUuRWHJkwRUc4fmspn9PN+Cf2KA8u1O2PQ3iUJBzTbj5QXyKwJ15P9FPZOrfiVDNBDKGnqMYP8TKWGw+Jp6KXf8/8wbX59e7Gu+jACRjpLoIw8hkBUboo2I1Bthioyj6Cj18CJu+yNRXHero0r4zrwS Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Mon 08-06-26 14:36:44, Ruoyu Wang wrote: > memcg1_init() allocates one soft-limit tree node per NUMA node and > then initializes the returned object. If kzalloc_node() fails, the rb_root > and lock initialization dereference NULL. > > The per-node soft-limit tree is required by memcg v1. Use nofail > GFP_KERNEL allocations for these init-time objects so the init path does > not continue without the required tree nodes. This is an early init code executing in during boot. Have you really seen this allocation failing? > Signed-off-by: Ruoyu Wang > --- > mm/memcontrol-v1.c | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/mm/memcontrol-v1.c b/mm/memcontrol-v1.c > index 433bba9dfe715..3f41a15d8a8cf 100644 > --- a/mm/memcontrol-v1.c > +++ b/mm/memcontrol-v1.c > @@ -2246,7 +2246,8 @@ static int __init memcg1_init(void) > for_each_node(node) { > struct mem_cgroup_tree_per_node *rtpn; > > - rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL, node); > + rtpn = kzalloc_node(sizeof(*rtpn), GFP_KERNEL | __GFP_NOFAIL, > + node); > > rtpn->rb_root = RB_ROOT; > rtpn->rb_rightmost = NULL; > -- > 2.51.0 -- Michal Hocko SUSE Labs