linux-kernel - Re: vmscan: Reclaim unevictable pages

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <SG2PR02MB3098B751EC6B8E32806A42FBE84B0@SG2PR02MB3098.apcprd02.prod.outlook.com>
Date:   Thu, 14 Mar 2019 08:23:10 +0000
From:   Pankaj Suryawanshi <pankaj.suryawanshi@...fochips.com>
To:     "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
CC:     "minchan@...nel.org" <minchan@...nel.org>
Subject: Re: vmscan: Reclaim unevictable pages

Below is the Error Msg :

[   24.718792] page dumped because: VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page))
[   24.726949] page->mem_cgroup:bd008c00
[   24.730693] ------------[ cut here ]------------
[   24.735304] kernel BUG at mm/vmscan.c:1350!
[   24.739478] Internal error: Oops - BUG: 0 [#1] PREEMPT SMP ARM

Solved the issue by below patch.

diff --git a/mm/vmscan.c b/mm/vmscan.c
index be56e2e..2e51edc 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -990,15 +990,17 @@ static unsigned long shrink_page_list(struct list_head *page_list,
                page = lru_to_page(page_list);
                list_del(&page->lru);

               if (!trylock_page(page)) {
                        goto keep;
               }

                VM_BUG_ON_PAGE(PageActive(page), page);

                sc->nr_scanned++;

                if (unlikely(!page_evictable(page)))
-                       goto activate_locked;
+                      goto cull_mlocked;

                if (!sc->may_unmap && page_mapped(page))
                        goto keep_locked;
@@ -1331,6 +1333,12 @@ static unsigned long shrink_page_list(struct list_head *page_list,
                } else
                        list_add(&page->lru, &free_pages);
                continue;
+cull_mlocked:
+                if (PageSwapCache(page))
+                        try_to_free_swap(page);
+                unlock_page(page);
+                list_add(&page->lru, &ret_pages);
+                continue;

 activate_locked:
                /* Not a candidate for swapping, so reclaim swap space. */

From: Pankaj Suryawanshi
Sent: 14 March 2019 13:23:53
To: linux-kernel@...r.kernel.org
Cc: minchan@...nel.org
Subject: vmscan: Reclaim unevictable pages

Hello ,

shrink_page_list() returns , number of pages reclaimed, when pages is unevictable it returns VM_BUG_ON_PAGE(PageLRU(page) || PageUnevicatble(page),page);

We can add the unevictable pages in reclaim list in shrink_page_list(), return total number of reclaim pages including unevictable pages, let the caller handle unevictable pages.

Regards,
Pankaj

************************************************************************************************************************************************************* eInfochips Business Disclaimer: This e-mail message and all attachments transmitted with it are intended solely for the use of the addressee and may contain legally privileged and confidential information. If the reader of this message is not the intended recipient, or an employee or agent responsible for delivering this message to the intended recipient, you are hereby notified that any dissemination, distribution, copying, or other use of this message or its attachments is strictly prohibited. If you have received this message in error, please notify the sender immediately by replying to this message and please delete it from your computer. Any views expressed in this message are those of the individual sender unless otherwise stated. Company has taken enough precautions to prevent the spread of viruses. However the company accepts no liability for any damage caused by any virus transmitted by this email. *************************************************************************************************************************************************************