diff options
| author | Miaohe Lin <[email protected]> | 2022-05-26 19:33:50 +0800 |
|---|---|---|
| committer | akpm <[email protected]> | 2022-05-27 08:55:18 -0700 |
| commit | 24c8e27e63224ce832b4723cb60632d3eddb55de (patch) | |
| tree | 7bfdfa301eb22eacbc930dbfc807823350146848 | |
| parent | 3e35142ef99fe6b4fe5d834ad43ee13cca10a2dc (diff) | |
mm/page_table_check: fix accessing unmapped ptep
ptep is unmapped too early, so ptep could theoretically be accessed while
it's unmapped. This might become a problem if/when CONFIG_HIGHPTE becomes
available on riscv.
Fix it by deferring pte_unmap() until page table checking is done.
[[email protected]: account for ptep alteration, per Matthew]
Link: https://lkml.kernel.org/r/[email protected]
Fixes: 80110bbfbba6 ("mm/page_table_check: check entries at pmd levels")
Signed-off-by: Miaohe Lin <[email protected]>
Acked-by: Pasha Tatashin <[email protected]>
Cc: Qi Zheng <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: David Rientjes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
| -rw-r--r-- | mm/page_table_check.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/page_table_check.c b/mm/page_table_check.c index 2458281bff89..bc55be28807f 100644 --- a/mm/page_table_check.c +++ b/mm/page_table_check.c @@ -251,11 +251,11 @@ void __page_table_check_pte_clear_range(struct mm_struct *mm, pte_t *ptep = pte_offset_map(&pmd, addr); unsigned long i; - pte_unmap(ptep); for (i = 0; i < PTRS_PER_PTE; i++) { __page_table_check_pte_clear(mm, addr, *ptep); addr += PAGE_SIZE; ptep++; } + pte_unmap(ptep - PTRS_PER_PTE); } } |