Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

mm/slab: fix warning caused by duplicate kmem_cache creation in kmem_buckets_create

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:

[ 2.325108] ------------[ cut here ]------------ [ 2.325135] kmem_cache of name 'memdup_user-16' already exists [ 2.325783] WARNING: CPU: 0 PID: 1 at mm/slab_common.c:107 __kmem_cache_create_args+0xb8/0x3b0 [ 2.327957] Modules linked in: [ 2.328550] CPU: 0 UID: 0 PID: 1 Comm: swapper/0 Not tainted 6.12.0-rc5mm-unstable-arm64+ #12 [ 2.328683] Hardware name: QEMU QEMU Virtual Machine, BIOS 2024.02-2 03/11/2024 [ 2.328790] pstate: 61000009 (nZCv daif -PAN -UAO -TCO +DIT -SSBS BTYPE=--) [ 2.328911] pc : __kmem_cache_create_args+0xb8/0x3b0 [ 2.328930] lr : __kmem_cache_create_args+0xb8/0x3b0 [ 2.328942] sp : ffff800083d6fc50 [ 2.328961] x29: ffff800083d6fc50 x28: f2ff0000c1674410 x27: ffff8000820b0598 [ 2.329061] x26: 000000007fffffff x25: 0000000000000010 x24: 0000000000002000 [ 2.329101] x23: ffff800083d6fce8 x22: ffff8000832222e8 x21: ffff800083222388 [ 2.329118] x20: f2ff0…