linux-kernel - Re: [PATCH] mm/slab: fix warning caused by duplicate kmem_cache creation in kmem_buckets

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <ZykLxG5Tyet5HcwL@casper.infradead.org>
Date: Mon, 4 Nov 2024 18:00:36 +0000
From: Matthew Wilcox <willy@...radead.org>
To: Koichiro Den <koichiro.den@...il.com>
Cc: vbabka@...e.cz, cl@...ux.com, penberg@...nel.org, rientjes@...gle.com,
	iamjoonsoo.kim@....com, akpm@...ux-foundation.org,
	roman.gushchin@...ux.dev, 42.hyeyoo@...il.com, kees@...nel.org,
	linux-mm@...ck.org, linux-kernel@...r.kernel.org,
	stable@...r.kernel.org
Subject: Re: [PATCH] mm/slab: fix warning caused by duplicate kmem_cache
 creation in kmem_buckets_create

On Tue, Nov 05, 2024 at 12:08:37AM +0900, Koichiro Den wrote:
> Commit b035f5a6d852 ("mm: slab: reduce the kmalloc() minimum alignment
> if DMA bouncing possible") reduced ARCH_KMALLOC_MINALIGN to 8 on arm64.
> However, with KASAN_HW_TAGS enabled, arch_slab_minalign() becomes 16.
> This causes kmalloc_caches[*][8] to be aliased to kmalloc_caches[*][16],
> resulting in kmem_buckets_create() attempting to create a kmem_cache for
> size 16 twice. This duplication triggers warnings on boot:

Wouldn't this be easier?

+++ b/arch/arm64/include/asm/cache.h
@@ -33,7 +33,11 @@
  * the CPU.
  */
 #define ARCH_DMA_MINALIGN      (128)
+#ifdef CONFIG_KASAN_HW_TAGS
+#define ARCH_KMALLOC_MINALIGN  (16)
+#else
 #define ARCH_KMALLOC_MINALIGN  (8)
+#endif

 #ifndef __ASSEMBLY__