2022-12-20 07:48:05

by Chih-En Lin

[permalink] [raw]
Subject: [PATCH v3 12/14] fs/proc: Support COW PTE with clear_refs_write

Before clearing the entry in COW-ed PTE, break COW PTE first.

Signed-off-by: Chih-En Lin <[email protected]>
---
fs/proc/task_mmu.c | 3 +++
1 file changed, 3 insertions(+)

diff --git a/fs/proc/task_mmu.c b/fs/proc/task_mmu.c
index 8a74cdcc9af00..7d34b036c1b96 100644
--- a/fs/proc/task_mmu.c
+++ b/fs/proc/task_mmu.c
@@ -1190,6 +1190,9 @@ static int clear_refs_pte_range(pmd_t *pmd, unsigned long addr,
if (pmd_trans_unstable(pmd))
return 0;

+ if (break_cow_pte(vma, pmd, addr) < 0)
+ return 0;
+
pte = pte_offset_map_lock(vma->vm_mm, pmd, addr, &ptl);
for (; addr != end; pte++, addr += PAGE_SIZE) {
ptent = *pte;
--
2.37.3