From: Ming Wang <wangming01@loongson.cn> stable inclusion from stable-v6.6.89 commit 2ca9380b12711afe95b3589bd82b59623b3c96b3 category: feature bugzilla: https://gitee.com/openeuler/kernel/issues/IC6CVG CVE: NA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- LoongArch's huge_pte_offset() currently returns a pointer to a PMD slot even if the underlying entry points to invalid_pte_table (indicating no mapping). Callers like smaps_hugetlb_range() fetch this invalid entry value (the address of invalid_pte_table) via this pointer. The generic is_swap_pte() check then incorrectly identifies this address as a swap entry on LoongArch, because it satisfies the !pte_present() && !pte_none() conditions. This misinterpretation, combined with a coincidental match by is_migration_entry() on the address bits, leads to kernel crashes in pfn_swap_entry_to_page(). Fix this at the architecture level by modifying huge_pte_offset() to check the PMD entry's content using pmd_none() before returning. If the entry is none (i.e., it points to invalid_pte_table), return NULL instead of the pointer to the slot. Change-Id: Ic3b605551c5fe4e21ee3d02606bd0340cddcbf91 Co-developed-by: Hongchen Zhang <zhanghongchen@loongson.cn> Signed-off-by: Hongchen Zhang <zhanghongchen@loongson.cn> Signed-off-by: Huacai Chen <chenhuacai@loongson.cn> Signed-off-by: Ming Wang <wangming01@loongson.cn> --- arch/loongarch/mm/hugetlbpage.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/loongarch/mm/hugetlbpage.c b/arch/loongarch/mm/hugetlbpage.c index 62ddcea0aa14..aca52c42e94e 100644 --- a/arch/loongarch/mm/hugetlbpage.c +++ b/arch/loongarch/mm/hugetlbpage.c @@ -47,7 +47,7 @@ pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, pmd = pmd_offset(pud, addr); } } - return (pte_t *) pmd; + return pmd_none(pmdp_get(pmd)) ? NULL : (pte_t *) pmd; } int pmd_huge(pmd_t pmd) -- 2.33.0