From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-dy1-f201.google.com (mail-dy1-f201.google.com [74.125.82.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id D404C351C18 for ; Wed, 18 Mar 2026 22:20:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773872416; cv=none; b=jhOSkdCCSjwpzqoAne0C9/jf8L34Kb1x90BZDzppC0Q+oQ8IJrNHAyOyuU5LqfyEpMvGTX6pr2Ykn63JbFHT3lz/qlOisBwT8a5B0YBCnJyP1BBjtVc3IC6u0FD4gLCSICkivONpxp7aS5jkrcaG32rgLK2QXogoPrjUbf5RsPo= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773872416; c=relaxed/simple; bh=PXrce2FV4fNoIetAEQuoqhiTqGcIX9SnWgvXZgFZL0k=; h=Date:In-Reply-To:Mime-Version:References:Message-ID:Subject:From: To:Cc:Content-Type; b=KGXDUARmry05yjFY+zruSrMrpDEzoSJLzcevHoxTElLhLIA7RVAiPyNJWGtdS5OFMWQYLufCAxcGkFQoh5IFkoBfxbDy9m2fcR+5d5SbIFO59m7Do3uhJ8iG8VKtTA4sizeilLwl/NLU78czgi/c3RUggCx+hwPD1m4aEdSe43I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com; spf=pass smtp.mailfrom=flex--bingjiao.bounces.google.com; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b=F1itBfS8; arc=none smtp.client-ip=74.125.82.201 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=reject dis=none) header.from=google.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=flex--bingjiao.bounces.google.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="F1itBfS8" Received: by mail-dy1-f201.google.com with SMTP id 5a478bee46e88-2bdd327d970so185879eec.1 for ; Wed, 18 Mar 2026 15:20:13 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20251104; t=1773872413; x=1774477213; darn=vger.kernel.org; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=8XjdRK+apGY2bi7TFVCOUhj0XNVIb0zT+0LrkX1AC80=; b=F1itBfS8gIK6/b5BnHvTHBeHfyBTLwdTOufZ8bFatpvc/BBhZ1JTLZVyhb2EkgKAIh BZSVkxShYoep2glD28OLTa/0dbwOl3HDtUqmiF3qWzKkHu5OU7xnzsByGCzc6lXmGWNw zUzzYuwCu1v1MEmX/fBnZdmC9dosJvhN+uR/ztcauHcZ4EXH2ku5OlzylhCSPfPO3cyX SYNMD7fLSr25YmVuELqcXsDUe+4STbbGZeePyI5IaufYpiUnhwu7KAg69VjfsCO0ItxU EisEjdynGZpX8Be9HXZHNPMJgwl87YY7P+n4HxOjmOWceHC4jL3GdPD6HlxuVQn6i1Bo AOzQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20251104; t=1773872413; x=1774477213; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=8XjdRK+apGY2bi7TFVCOUhj0XNVIb0zT+0LrkX1AC80=; b=p5HxvCfDQsv23QpD2f6YMmtyAwuSUTR1vnL4L3VrY8TWUkNC1RpI8S9YFjFfNUGsrX X4IycUq6UVxVqHz0gccJ6NZa3zles4act5lCqtzuAf+n3LPdvDx5a2525+VKJaIi5zvO +/xqxGsVG01ihss0dH1VdFpD2tJrr+wn+9KwOU/5YrwQeyl18jfu/vRpMoVVjnURaZRF 3RTQmUHQRcCUXtfKnnPD5XyeQHfXeAdsblftfgZuCRZg4VNjZOY0jLsv0jSuPqMJvMJ/ tABOMWJBLZ7s0JjYJQp2Ss8drvlCOnVECb1kyWij2+fdDMzdmTXIbOP3jqMHylZ/rKBA 0Xjw== X-Forwarded-Encrypted: i=1; AJvYcCUDpqexxQ0F5ao492crm5XE+M/uZqZg34ZhE9nqEkYywRCNng5tGOlxYHcVExc5l4M2YU5Dw9S9@vger.kernel.org X-Gm-Message-State: AOJu0Yyn10B5vpRLw2mAx79ZwnhDFCpZ77i4DAyXhz8iWtVqI5GpXlqe 98k9pl+qdGevWgd9jGToM94mGcvru8+sWCx+c7mrr8YjZ37hjXi7EecekbXv256naViS3pLTH6k bAykwuZIYRijhog== X-Received: from dybmn16.prod.google.com ([2002:a05:7300:d210:b0:2c0:d899:d1a2]) (user=bingjiao job=prod-delivery.src-stubby-dispatcher) by 2002:a05:7300:e82c:b0:2be:1a8e:10bb with SMTP id 5a478bee46e88-2c0f3c333d0mr528958eec.12.1773872412419; Wed, 18 Mar 2026 15:20:12 -0700 (PDT) Date: Wed, 18 Mar 2026 22:19:46 +0000 In-Reply-To: <20260318215629.2849052-1-bingjiao@google.com> Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20260318215629.2849052-1-bingjiao@google.com> X-Mailer: git-send-email 2.53.0.851.ga537e3e6e9-goog Message-ID: <20260318221957.2979346-1-bingjiao@google.com> Subject: [PATCH v3] mm/memcontrol: fix reclaim_options leak in try_charge_memcg() From: Bing Jiao To: bingjiao@google.com Cc: akpm@linux-foundation.org, axelrasmussen@google.com, baohua@kernel.org, bhe@redhat.com, cgroups@vger.kernel.org, chrisl@kernel.org, david@kernel.org, hannes@cmpxchg.org, joshua.hahnjy@gmail.com, kasong@tencent.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, ljs@kernel.org, mhocko@kernel.org, muchun.song@linux.dev, nphamcs@gmail.com, rientjes@google.com, roman.gushchin@linux.dev, shakeel.butt@linux.dev, shikemeng@huaweicloud.com, weixugc@google.com, yosry@kernel.org, youngjun.park@lge.com, yuanchu@google.com, zhengqi.arch@bytedance.com Content-Type: text/plain; charset="UTF-8" In try_charge_memcg(), the 'reclaim_options' variable is initialized once at the start of the function. However, the function contains a retry loop. If reclaim_options were modified during an iteration (e.g., by encountering a memsw limit), the modified state would persist into subsequent retries. This leads to incorrect reclaim behavior. Specifically, MEMCG_RECLAIM_MAY_SWAP is cleared when the combined memcg->memsw limit is reached. After reclaimation attemps, a subsequent retry may successfully charge memcg->memsw but fail on the memcg->memory charge. In this case, swapping should be permitted, but the carried-over state prevents it. Fix by moving the initialization of 'reclaim_options' inside the retry loop, ensuring a clean state for every reclaim attempt. Fixes: 6539cc053869 ("mm: memcontrol: fold mem_cgroup_do_charge()") Signed-off-by: Bing Jiao Reviewed-by: Yosry Ahmed --- v3: - Corrected the Fixes tag (Yosry). mm/memcontrol.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/mm/memcontrol.c b/mm/memcontrol.c index a47fb68dd65f..303ac622d22d 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -2558,7 +2558,7 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask, struct page_counter *counter; unsigned long nr_reclaimed; bool passed_oom = false; - unsigned int reclaim_options = MEMCG_RECLAIM_MAY_SWAP; + unsigned int reclaim_options; bool drained = false; bool raised_max_event = false; unsigned long pflags; @@ -2572,6 +2572,7 @@ static int try_charge_memcg(struct mem_cgroup *memcg, gfp_t gfp_mask, /* Avoid the refill and flush of the older stock */ batch = nr_pages; + reclaim_options = MEMCG_RECLAIM_MAY_SWAP; if (!do_memsw_account() || page_counter_try_charge(&memcg->memsw, batch, &counter)) { if (page_counter_try_charge(&memcg->memory, batch, &counter)) -- 2.53.0.851.ga537e3e6e9-goog