From nobody Mon Apr 6 15:50:54 2026 Received: from mail-dy1-f202.google.com (mail-dy1-f202.google.com [74.125.82.202]) (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 E0F7336605B for ; Wed, 18 Mar 2026 22:20:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=74.125.82.202 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1773872416; cv=none; b=O7jc0ZTOyod98/8TMapomd2mfWwe2FlYUOnwLk8iXUAF7Dr86WD6zRgYTXeD541g1HcAWMPiSgh9MlpSn484OFK3XpqSulAYKT0JGj5klUUhkY9WD2cUExYSnDeeWzzTyxg1R10mT9bg0B3fwY1ei0uhC9a+l7phjl5COcmzwco= 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=74.125.82.202 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-f202.google.com with SMTP id 5a478bee46e88-2bdd327d970so185878eec.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=XWbIxCzquTvTlTmCHncu2uWjCM46GYcRPzvNfN9GR+sJU73SO7eAH3ylmytMxhhwV3 DgT7JYf2m5RuiA+S6lYLpR08J/VdaTE61ZblS1HJb4nsq/j4VdSd6cBzKFNu/kOPaDpQ vXH7A68D9jf44xasICpZBkZ2kzuX5IoQnaRIZuS/jKV/68smrubYBnx6trcCkmtEOl1Z 5NvQqT5aHaMqnzCWHETr40MkviOqDT+sr8YU62VWTaf6pNgX5Rm4TEFP0tYBgDopx+cM zyFHlFbclFadEjCy834k44KHTIgRzAkSYpx3G9BqxN6EB79zL6st5Dscl8/mElVyjAAN DdUA== X-Forwarded-Encrypted: i=1; AJvYcCVV7oDJRzExoWnaO9EcYGTXtiXL4gdC+1dgUWf95tkEV/cft6KNQYY3pkm5W/7XI8zqtzF//FUxzd+BdCg=@vger.kernel.org X-Gm-Message-State: AOJu0YzSCdpw7Yr7IaqJePwjzQJU186o8da+MEpfZNcm7laeU9M3cini VX/N3qoSIMCiIPRiRSeXpu1xHOxbqeFrgBsWzDYcfCLVolEIpcTFLJsflor3/YT8+nM3lXb2haI Si7BfBBsqg42LGg== 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: linux-kernel@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-Transfer-Encoding: quoted-printable 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 Acked-by: Johannes Weiner Acked-by: Michal Hocko Acked-by: Shakeel Butt --- 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 =3D false; - unsigned int reclaim_options =3D MEMCG_RECLAIM_MAY_SWAP; + unsigned int reclaim_options; bool drained =3D false; bool raised_max_event =3D 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 =3D nr_pages; + reclaim_options =3D 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