Re: [PATCH] mm/slab: Fix a kmemleak in kmem_cache_destroy()

Chengming Zhou
2024-02-28T09:31:18Z

On 2024/2/28 11:04, Xiaolei Wang wrote:
> For earlier kmem cache creation, slab_sysfs_init() has not been called.
> Consequently, kmem_cache_destroy() cannot utilize kobj_type::release to
> release the kmem_cache structure. Therefore, tweak kmem_cache_release()
> to use slab_kmem_cache_release() for releasing kmem_cache when slab_state
> isn't FULL. This will fixes the memory leaks like following:
>
> unreferenced object 0xffff0000c2d87080 (size 128):
> comm "swapper/0", pid 1, jiffies 4294893428
> hex dump (first 32 bytes):
> 00 00 00 00 ad 4e ad de ff ff ff ff 6b 6b 6b 6b .....N......kkkk
> ff ff ff ff ff ff ff ff b8 ab 48 89 00 80 ff ff.....H.....
> backtrace (crc 8819d0f6):
> [<ffff80008317a298>] kmemleak_alloc+0xb0/0xc4
> [<ffff8000807e553c>] kmem_cache_alloc_node+0x288/0x3a8
> [<ffff8000807e95f0>] __kmem_cache_create+0x1e4/0x64c
> [<ffff8000807216bc>] kmem_cache_create_usercopy+0x1c4/0x2cc
> [<ffff8000807217e0>] kmem_cache_create+0x1c/0x28
> [<ffff8000819f6278>] arm_v7s_alloc_pgtable+0x1c0/0x6d4
> [<ffff8000819f53a0>] alloc_io_pgtable_ops+0xe8/0x2d0
> [<ffff800084b2d2c4>] arm_v7s_do_selftests+0xe0/0x73c
> [<ffff800080016b68>] do_one_initcall+0x11c/0x7ac
> [<ffff800084a71ddc>] kernel_init_freeable+0x53c/0xbb8
> [<ffff8000831728d8>] kernel_init+0x24/0x144
> [<ffff800080018e98>] ret_from_fork+0x10/0x20
>
> Signed-off-by: Xiaolei Wang <xiaolei.wang@windriver.com>

Looks good to me. And I notice the PARTIAL_NODE state of slab_state is
also useless since SLAB removed.

Reviewed-by: Chengming Zhou <chengming.zhou@linux.dev>

Thanks.