lkml.org 
[lkml]   [2021]   [Dec]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH] mm/madvise: elevate page refcount while isolating in process_madvise()
Date
The documentation of isolate_lru_page() says that, "it must be called
with an elevated refcount on the page", which is not followed while
isolating pages in process_madvise() system call with advise
MADV_PAGEOUT. Fix it.

Signed-off-by: Charan Teja Reddy <quic_charante@quicinc.com>
---
mm/madvise.c | 11 +++++++++--
1 file changed, 9 insertions(+), 2 deletions(-)

diff --git a/mm/madvise.c b/mm/madvise.c
index 0734db8..4c4a8e9 100644
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -317,6 +317,7 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
pte_t *orig_pte, *pte, ptent;
spinlock_t *ptl;
struct page *page = NULL;
+ int ret;
LIST_HEAD(page_list);

if (fatal_signal_pending(current))
@@ -373,12 +374,15 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
ClearPageReferenced(page);
test_and_clear_page_young(page);
if (pageout) {
- if (!isolate_lru_page(page)) {
+ get_page(page);
+ ret = isolate_lru_page(page);
+ if (!ret) {
if (PageUnevictable(page))
putback_lru_page(page);
else
list_add(&page->lru, &page_list);
}
+ put_page(page);
} else
deactivate_page(page);
huge_unlock:
@@ -459,12 +463,15 @@ static int madvise_cold_or_pageout_pte_range(pmd_t *pmd,
ClearPageReferenced(page);
test_and_clear_page_young(page);
if (pageout) {
- if (!isolate_lru_page(page)) {
+ get_page(page);
+ ret = isolate_lru_page(page);
+ if (!ret) {
if (PageUnevictable(page))
putback_lru_page(page);
else
list_add(&page->lru, &page_list);
}
+ put_page(page);
} else
deactivate_page(page);
}
--
2.7.4
\
 
 \ /
  Last update: 2021-12-15 13:24    [W:2.466 / U:0.152 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site