diff options
| author | Ming Wang <wangming01@loongson.cn> | 2025-04-24 20:15:47 +0800 |
|---|---|---|
| committer | Huacai Chen <chenhuacai@loongson.cn> | 2025-04-26 09:58:12 +0800 |
| commit | bd51834d1cf65a2c801295d230c220aeebf87a73 (patch) | |
| tree | 2e29953b31ac94381968adc1f1c7e4e479bf5f93 | |
| parent | c37325cbd91abe3bfab280b3b09947155abe8e07 (diff) | |
LoongArch: Return NULL from huge_pte_offset() for invalid PMD
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 invalid (i.e., it points to invalid_pte_table), return NULL
instead of the pointer to the slot.
Cc: stable@vger.kernel.org
Acked-by: Peter Xu <peterx@redhat.com>
Co-developed-by: Hongchen Zhang <zhanghongchen@loongson.cn>
Signed-off-by: Hongchen Zhang <zhanghongchen@loongson.cn>
Signed-off-by: Ming Wang <wangming01@loongson.cn>
Signed-off-by: Huacai Chen <chenhuacai@loongson.cn>
| -rw-r--r-- | arch/loongarch/mm/hugetlbpage.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/arch/loongarch/mm/hugetlbpage.c b/arch/loongarch/mm/hugetlbpage.c index e4068906143b..cea84d7f2b91 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; } uint64_t pmd_to_entrylo(unsigned long pmd_val) |