From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 19A864B0482; Fri, 7 Aug 2026 14:50:01 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786114203; cv=none; b=jGzlQhNS7vIiQtBJuntQIuPIt5VrSCnIG7ZGsgQP7IknoXEy9myRNV/rBJCWI4xUpkObM4HWJxFzva32EgTVdftloX8gYW6ysf18oTdw/6N305ZVw+ZBtEbpINnpcj8JP3OLa4ZrJU/roMt74PHwMAIaWkDNB3ObNeJ9vrqWVQI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786114203; c=relaxed/simple; bh=BJ2uEqZ8jgDP5WcfCzpfzej3GtXmpqToHoxBatDxUNA=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=GhOLHOqrWLBWoCQin/vw2IaFp8qfIjyznY9qmgXEboPA+8mH1OxJs0tUWQ6MqmUrXhK/oS7wRSmKHymh+G7gVEeUg74YcXJ79VjQIm5Duzb9zuhoSQ3FkA5tA+x93IpIgmIjcHw6UhtHFgkOB7nLl5Ti16KpNJ6hr9Kjb/gh6G4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=xiMGObqC; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b="xiMGObqC" Received: by smtp.kernel.org (Postfix) with ESMTPSA id CB6C41F000E9; Fri, 7 Aug 2026 14:50:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786114201; bh=pfNsIzxZMQWdSvpev7PMowm1Dpq5aIUMZGtH9XNAEEw=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=xiMGObqCs1nBjaOmUqJbi652k5tlPWVMG4QkKLq3d/FDEi1zcRVeidtqHCy2+emDp AQgFiOd1k1lfc/wJiJFTEUjYV5o9NKhQArajz/7MqwUHfwFT069o7PwexDSDsAxcmD QBByeFx8Lwhoq1IdjI6Ot/rWvtsWk6ycTu7JAfeU= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Breno Leitao , Joshua Hahn , Johannes Weiner , SeongJae Park , Shakeel Butt , Michal Hocko , Muchun Song , Roman Gushchin , Andrew Morton Subject: [PATCH 6.12 181/337] mm: memcg: initialize *locked in memcg1_oom_prepare() stub Date: Fri, 7 Aug 2026 16:36:24 +0200 Message-ID: <20260807143422.483464410@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260807143418.516897842@linuxfoundation.org> References: <20260807143418.516897842@linuxfoundation.org> User-Agent: quilt/0.69 X-stable: review X-Patchwork-Hint: ignore Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 6.12-stable review patch. If anyone has any objections, please let me know. ------------------ From: Breno Leitao commit 1833ce36b35426504c64600c94f322437ea44bb2 upstream. mem_cgroup_oom() passes an uninitialized "locked" to memcg1_oom_prepare() and reads it back in memcg1_oom_finish(): bool locked, ret; ... if (!memcg1_oom_prepare(memcg, &locked)) return false; ret = mem_cgroup_out_of_memory(memcg, mask, order); memcg1_oom_finish(memcg, locked); This relies on memcg1_oom_prepare() setting *locked whenever it returns true. The CONFIG_MEMCG_V1=y version does, but the stub used when CONFIG_MEMCG_V1=n returns true without touching *locked, so memcg1_oom_finish() consumes an uninitialized value. On a memcg OOM this is reported by UBSAN: UBSAN: invalid-load in mm/memcontrol.c:1932:27 load of value 0 is not a valid value for type 'bool' (aka '_Bool') Initialize *locked to false in the stub; with cgroup v1 compiled out there is no OOM lock to take. Link: https://lore.kernel.org/20260716-memcg-oom-uninit-locked-v2-1-63631d878eb4@debian.org Fixes: e93d4166b40a ("mm: memcg: put cgroup v1-specific code under a config option") Signed-off-by: Breno Leitao Reviewed-by: Joshua Hahn Acked-by: Johannes Weiner Reviewed-by: SeongJae Park Acked-by: Shakeel Butt Cc: Michal Hocko Cc: Muchun Song Cc: Roman Gushchin Cc: Shakeel Butt Cc: Signed-off-by: Andrew Morton Signed-off-by: Greg Kroah-Hartman --- mm/memcontrol-v1.h | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) --- a/mm/memcontrol-v1.h +++ b/mm/memcontrol-v1.h @@ -133,7 +133,11 @@ static inline void memcg1_soft_limit_res static inline bool memcg1_wait_acct_move(struct mem_cgroup *memcg) { return false; } static inline void memcg1_css_offline(struct mem_cgroup *memcg) {} -static inline bool memcg1_oom_prepare(struct mem_cgroup *memcg, bool *locked) { return true; } +static inline bool memcg1_oom_prepare(struct mem_cgroup *memcg, bool *locked) +{ + *locked = false; + return true; +} static inline void memcg1_oom_finish(struct mem_cgroup *memcg, bool locked) {} static inline void memcg1_oom_recover(struct mem_cgroup *memcg) {}