From: Muchun Song <songmuchun@bytedance.com> stable inclusion from stable-v6.6.142 commit 686b4283f82cd630fafd7ca9b03dfc080b3ec8fa category: bugfix bugzilla: https://atomgit.com/src-openeuler/kernel/issues/16374 CVE: CVE-2026-64182 Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- commit 03a2cc1756a0570f887d624cd6c535ea0cbd4951 upstream. memblk_nr_poison_inc() and memblk_nr_poison_sub() look up a memory block via find_memory_block_by_id(), which acquires a reference to the memory block device. Both helpers use the returned memory block without dropping that reference, leaking the device reference on each successful lookup. Drop the reference after updating nr_hwpoison. Link: https://lore.kernel.org/20260428085219.1316047-3-songmuchun@bytedance.com Fixes: 5033091de814 ("mm/hwpoison: introduce per-memory_block hwpoison counter") Signed-off-by: Muchun Song <songmuchun@bytedance.com> Reviewed-by: Miaohe Lin <linmiaohe@huawei.com> Acked-by: Oscar Salvador <osalvador@suse.de> Acked-by: David Hildenbrand (Arm) <david@kernel.org> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: "Huang, Ying" <huang.ying.caritas@gmail.com> Cc: Naoya Horiguchi <nao.horiguchi@gmail.com> Cc: "Rafael J. Wysocki" <rafael@kernel.org> Cc: Vishal Verma <vishal.l.verma@intel.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Signed-off-by: Lin Ruifeng <linruifeng4@huawei.com> --- drivers/base/memory.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/drivers/base/memory.c b/drivers/base/memory.c index 32a7bbc00599..2196b53a62f7 100644 --- a/drivers/base/memory.c +++ b/drivers/base/memory.c @@ -1306,8 +1306,10 @@ void memblk_nr_poison_inc(unsigned long pfn) const unsigned long block_id = pfn_to_block_id(pfn); struct memory_block *mem = find_memory_block_by_id(block_id); - if (mem) + if (mem) { atomic_long_inc(&mem->nr_hwpoison); + put_device(&mem->dev); + } } void memblk_nr_poison_sub(unsigned long pfn, long i) @@ -1315,8 +1317,10 @@ void memblk_nr_poison_sub(unsigned long pfn, long i) const unsigned long block_id = pfn_to_block_id(pfn); struct memory_block *mem = find_memory_block_by_id(block_id); - if (mem) + if (mem) { atomic_long_sub(i, &mem->nr_hwpoison); + put_device(&mem->dev); + } } static unsigned long memblk_nr_poison(struct memory_block *mem) -- 2.34.1