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 982824BF949; Mon, 12 Oct 2026 17:55:30 +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=1791827731; cv=none; b=tXKXoBbWKHvVD/uA3yI5lieoEC8KFiMTEIG1Ur543buPqL+upIsK/5u6Yi/ejEcaKFtHRa+DxpBxsZsd2Y8J2Qpm7gVKWdHQcmpScU4npFR1ksSEad9zc1RVjcbyt61FL2iUXB0d+WZk/D3YKoZEGWZcGZx35jmt73NkFeUBHNs= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791827731; c=relaxed/simple; bh=iQCsw8uWpkZoYq4YSbm5YHjbLGN+kSPUtNUTOefnYNs=; h=Message-ID:Date:MIME-Version:Subject:To:Cc:References:From: In-Reply-To:Content-Type; b=NR6NNcFusZDjQ+fiGxXZh4jNm0unfZZ1AkoFiTi9JaysXOyvNbS8aDqrKCtBZOi2+p/9OH34Xt+g4LMGmQ/tu5aCXsaY9kc54ohSIiUuSMJsJMDRpNXbDTOJyzUOI76wQVzmI3Rkkpjd4tPWc1HLiXU9Hj3m5k5h44QoTeGAKnw= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=BVrURADp; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="BVrURADp" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 6F0061F0089B; Mon, 12 Oct 2026 17:55:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791827730; bh=J6n50eQ6V6pm/yCK3IlU6OVvJN5nG9cOEO098JYwwjc=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=BVrURADp1C8qVzrqLzvEPNHgiBxziCjaeMHJ0+mFb6UlZRKScmQV7vpqt/3eMKKBf Kt1OVCcCSI5QxX27NGiDPfN6DnmsKHHBzNWExVlaijVqx98s6g+04t7Qha0RzzU+cm EU36JDQ9rY/7RdGGhcJgswDE11gV62/RoITeMTPtTSbRV/lJMsD0+T2+lw5+27XDeZ NSIEfvd8kHFDWoeeMCgo96BzPS31dyiC1FJkZLXFwNVhgWaJZ6epV8PYaBoAtbdnQW KLpAmZeDS4J92RhFNACKOzt/BNJ6RTT1HruDVrTS74WhOCBTEDymQI0hNNKqq/V7mL X5vM3rxGFOIrg== Message-ID: <38befa8c-3885-44eb-813c-0ee34cd55248@kernel.org> Date: Mon, 12 Oct 2026 19:55:25 +0200 Precedence: bulk X-Mailing-List: cgroups@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next v6 2/8] ipc, msg: Account msg_msg allocations with GFP_KERNEL_ACCOUNT again Content-Language: en-US To: Kees Cook Cc: Christian Brauner , Jan Kara , Andrew Morton , Roman Gushchin , Johannes Weiner , Michal Hocko , Shakeel Butt , Muchun Song , cgroups@vger.kernel.org, linux-mm@kvack.org, Pedro Falcato , Kuniyuki Iwashima , linux-hardening@vger.kernel.org, linux-kernel@vger.kernel.org References: <20261006092030.got.500-kees@kernel.org> <20261006092035.166776-2-kees@kernel.org> From: "Vlastimil Babka (SUSE)" Autocrypt: addr=vbabka@kernel.org; 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charset=UTF-8 Content-Transfer-Encoding: 7bit On 10/6/26 11:20, Kees Cook wrote: > Since commit 734bbc1c97ea7 ("ipc, msg: Use dedicated slab buckets for > alloc_msg()"), alloc_msg() allocates with GFP_KERNEL, and a msg_msg is > accounted only through SLAB_ACCOUNT on its bucket caches. With > CONFIG_SLAB_BUCKETS=n, kmem_buckets_create() creates no caches and > kmem_buckets_alloc() is a GFP_KERNEL kmalloc() from the general caches, > which do not account it; the same happens when kmem_buckets_create() > fails. Either way, the allocation is not charged to the sender's memory > cgroup. > > Allocate with GFP_KERNEL_ACCOUNT again, as before that commit. Memcg > charges such an allocation in whichever cache serves it, so drop the > SLAB_ACCOUNT, which no longer adds anything. > > Build tested ARCH=x86_64 defconfig with GCC 16.2.0, with > CONFIG_SLAB_BUCKETS as y and n. > > Fixes: 734bbc1c97ea7 ("ipc, msg: Use dedicated slab buckets for alloc_msg()") > Assisted-by: LLM > Signed-off-by: Kees Cook Could we, for the purposes of a backportable fix, just have both SLAB_ACCOUNT and GFP_KERNEL_ACCOUNT in place? That should do the right thing regardless of CONFIG_SLAB_BUCKETS state, no? > --- > ipc/msgutil.c | 5 +++-- > 1 file changed, 3 insertions(+), 2 deletions(-) > > diff --git a/ipc/msgutil.c b/ipc/msgutil.c > index e28f0cecb2ec..1ba8e59cb255 100644 > --- a/ipc/msgutil.c > +++ b/ipc/msgutil.c > @@ -43,7 +43,7 @@ static kmem_buckets *msg_buckets __ro_after_init; > > static int __init init_msg_buckets(void) > { > - msg_buckets = kmem_buckets_create("msg_msg", SLAB_ACCOUNT, > + msg_buckets = kmem_buckets_create("msg_msg", 0, > sizeof(struct msg_msg), > DATALEN_MSG, NULL); > > @@ -58,7 +58,8 @@ static struct msg_msg *alloc_msg(size_t len) > size_t alen; > > alen = min(len, DATALEN_MSG); > - msg = kmem_buckets_alloc(msg_buckets, sizeof(*msg) + alen, GFP_KERNEL); > + msg = kmem_buckets_alloc(msg_buckets, sizeof(*msg) + alen, > + GFP_KERNEL_ACCOUNT); > if (msg == NULL) > return NULL; >