lkml.org 
[lkml]   [2018]   [Mar]   [23]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
From
Subject[PATCH 4.9 128/177] mm: hwpoison: call shake_page() after try_to_unmap() for mlocked page
Date
4.9-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>


[ Upstream commit 286c469a988fbaf68e3a97ddf1e6c245c1446968 ]

Memory error handler calls try_to_unmap() for error pages in various
states. If the error page is a mlocked page, error handling could fail
with "still referenced by 1 users" message. This is because the page is
linked to and stays in lru cache after the following call chain.

try_to_unmap_one
page_remove_rmap
clear_page_mlock
putback_lru_page
lru_cache_add

memory_failure() calls shake_page() to hanlde the similar issue, but
current code doesn't cover because shake_page() is called only before
try_to_unmap(). So this patches adds shake_page().

Fixes: 23a003bfd23ea9ea0b7756b920e51f64b284b468 ("mm/madvise: pass return code of memory_failure() to userspace")
Link: http://lkml.kernel.org/r/20170417055948.GM31394@yexl-desktop
Link: http://lkml.kernel.org/r/1493197841-23986-3-git-send-email-n-horiguchi@ah.jp.nec.com
Signed-off-by: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Reported-by: kernel test robot <lkp@intel.com>
Cc: Xiaolong Ye <xiaolong.ye@intel.com>
Cc: Chen Gong <gong.chen@linux.intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
mm/memory-failure.c | 8 ++++++++
1 file changed, 8 insertions(+)

--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -921,6 +921,7 @@ static int hwpoison_user_mappings(struct
int ret;
int kill = 1, forcekill;
struct page *hpage = *hpagep;
+ bool mlocked = PageMlocked(hpage);

/*
* Here we are interested only in user-mapped pages, so skip any
@@ -985,6 +986,13 @@ static int hwpoison_user_mappings(struct
pfn, page_mapcount(hpage));

/*
+ * try_to_unmap() might put mlocked page in lru cache, so call
+ * shake_page() again to ensure that it's flushed.
+ */
+ if (mlocked)
+ shake_page(hpage, 0);
+
+ /*
* Now that the dirty bit has been propagated to the
* struct page and all unmaps done we can decide if
* killing is needed or not. Only kill when the page

\
 
 \ /
  Last update: 2018-03-23 12:13    [W:0.895 / U:0.116 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site