From: Harry Yoo <harry@kernel.org>
To: Kees Cook <kees@kernel.org>
Cc: "Vlastimil Babka" <vbabka@kernel.org>,
"Andrew Morton" <akpm@linux-foundation.org>,
"Hao Li" <hao.li@linux.dev>, "Christoph Lameter" <cl@gentwo.org>,
"David Rientjes" <rientjes@google.com>,
"Roman Gushchin" <roman.gushchin@linux.dev>,
linux-mm@kvack.org, "Pedro Falcato" <pfalcato@suse.de>,
"Kuniyuki Iwashima" <kuniyu@google.com>,
linux-hardening@vger.kernel.org,
"Jakub Kicinski" <kuba@kernel.org>,
"David S. Miller" <davem@davemloft.net>,
"Eric Dumazet" <edumazet@google.com>,
"Paolo Abeni" <pabeni@redhat.com>,
"Simon Horman" <horms@kernel.org>,
"Jason Xing" <kerneljasonxing@gmail.com>,
"Björn Töpel" <bjorn@kernel.org>,
"Jiayuan Chen" <jiayuan.chen@linux.dev>,
"Willem de Bruijn" <willemb@google.com>,
linux-kernel@vger.kernel.org, netdev@vger.kernel.org
Subject: Re: [PATCH v4 2/7] mm/slab: Give bucket caches the alignment of the caches they mirror
Date: Thu, 24 Sep 2026 19:22:58 +0100 [thread overview]
Message-ID: <arViR2Miz61-3fV4@thinkstation> (raw)
In-Reply-To: <202609211620.342AAA61@keescook>
On Mon, Sep 21, 2026 at 04:25:25PM -0700, Kees Cook wrote:
> On Mon, Sep 21, 2026 at 02:17:21PM +0100, Harry Yoo wrote:
> > On Mon, Sep 21, 2026 at 12:58:13AM -0700, Kees Cook wrote:
> > > if (WARN_ON(!cache_name))
> > > goto fail;
> > > (*b)[aligned_idx] = kmem_cache_create_usercopy(cache_name, size,
> > > - 0, flags, cache_useroffset,
> > > + kmalloc_caches[KMALLOC_NORMAL][idx]->align,
> > > + flags, cache_useroffset,
> > > cache_usersize, ctor);
> > > kfree(cache_name);
> > > if (WARN_ON(!(*b)[aligned_idx]))
>
> It looks "obviously correct", but I probably failed to correctly
> describe it. I'm happy to do whatever here.
That is correct, but is there any reason why kmem_buckets users should
not specify their own alignment requirement and inherit the alignment
from kmalloc?
For DMA yeah it might be confusing for every user to figure out that
the alignment should be __kmalloc_minalign(), but otherwise there isn't
really a good enough reason to inherit the alignment from kmalloc, no?
--
Cheers,
Harry / Hyeonggon
next prev parent reply other threads:[~2026-09-24 18:23 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-09-21 7:58 [PATCH v4 0/7] net: skb: isolate skb data area allocations into a separate bucket Kees Cook
2026-09-21 7:58 ` [PATCH v4 1/7] mm/slab: Mark the kmem_buckets_create() context as a Context: section Kees Cook
2026-09-21 12:03 ` Harry Yoo
2026-09-22 9:58 ` Pedro Falcato
2026-09-25 8:38 ` Hao Li
2026-09-21 7:58 ` [PATCH v4 2/7] mm/slab: Give bucket caches the alignment of the caches they mirror Kees Cook
2026-09-21 13:17 ` Harry Yoo
2026-09-21 23:25 ` Kees Cook
2026-09-24 18:22 ` Harry Yoo [this message]
2026-09-25 1:00 ` Kees Cook
2026-09-21 7:58 ` [PATCH v4 3/7] mm/slab: Add kmem_buckets_destroy() Kees Cook
2026-09-21 7:58 ` [PATCH v4 4/7] mm/slab: Add tests for the existing kmem_buckets behaviour Kees Cook
2026-09-21 7:58 ` [PATCH v4 5/7] mm/slab: Provide kmalloc type fallback for bucket allocations Kees Cook
2026-09-22 10:11 ` Pedro Falcato
2026-09-21 7:58 ` [PATCH v4 6/7] mm/slab: Let a bucket set handle __GFP_ACCOUNT Kees Cook
2026-09-21 13:25 ` Harry Yoo
2026-09-21 23:26 ` Kees Cook
2026-09-22 10:20 ` Pedro Falcato
2026-09-21 7:58 ` [PATCH v4 7/7] net: skb: isolate skb data area allocations into a separate bucket Kees Cook
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