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 B86E8397958; Fri, 7 Aug 2026 15:43:01 +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=1786117382; cv=none; b=p+iJWdjdPcODrSvwSYa/c9TJQj7fSaOCsJFVvVcYM4cRIvsqNKI0XErmjSr2Myh9UvlNQ7+8ZKO7BCloSg6eZZRcEGyT36V0BwaU9VDMbyyVhwp6jm00xGTjAPmwRviZ8P4Geep7Uc6S0prL57CCqdhLylIjMi2iRNOFM39Me+k= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1786117382; c=relaxed/simple; bh=Ofecrbf+Narxx7V4l7hscqcj7Tqs7k4icWQjJD99bd0=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=oMvwKSaQ0PL3AB0eLJoh62nU58HHkEYY3BTPuLYJvInfV0d2lpVRwfloTU6OqT4g8rysheoIxa+rHnaBk+gOax3TCTbEC6bP6g1RlYt5qm1ciphW9yol9aTykfk9SWeV+j2NNyyzTNUNrUlRoIrKfzvEJoL8EZ8fX+L0fmuhW5Y= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linuxfoundation.org header.i=@linuxfoundation.org header.b=Da4ZTN2v; 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="Da4ZTN2v" Received: by smtp.kernel.org (Postfix) with ESMTPSA id D01071F00A3A; Fri, 7 Aug 2026 15:43:00 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linuxfoundation.org; s=korg; t=1786117381; bh=G6wfEr3x7SQUOwFHNOz8rzfFGHzHJUdmGhDQJhO/hTo=; h=From:To:Cc:Subject:Date:In-Reply-To:References; b=Da4ZTN2v0ToHr+Zg9TUqumHesHX668Cj+8+o0AlKR+Cg+/yFIvPGvwZ+YfvoS7LpD YTe826p4X3ROYtP0IUeisP9lZ4mVDNCCxlJxYFxAOisUe3jdXLpyGsZoRq0xgd6jM1 SnPHEPv7CGLom8kM1cgjDbunbUkGXAO1mns5At0E= 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 7.1 297/438] mm: memcg: initialize *locked in memcg1_oom_prepare() stub Date: Fri, 7 Aug 2026 16:38:13 +0200 Message-ID: <20260807143434.305097468@linuxfoundation.org> X-Mailer: git-send-email 2.55.0 In-Reply-To: <20260807143428.008222056@linuxfoundation.org> References: <20260807143428.008222056@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 7.1-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 @@ -107,7 +107,11 @@ static inline void memcg1_remove_from_tr static inline void memcg1_soft_limit_reset(struct mem_cgroup *memcg) {} 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) {}