queue-4.19/mm-vmscan.c-fix-trying-to-reclaim-unevictable-lru-page.patch

   1 From a58f2cef26e1ca44182c8b22f4f4395e702a5795 Mon Sep 17 00:00:00 2001
   2 From: Minchan Kim <minchan@kernel.org>
   3 Date: Thu, 13 Jun 2019 15:56:15 -0700
   4 Subject: mm/vmscan.c: fix trying to reclaim unevictable LRU page
   5
   6 From: Minchan Kim <minchan@kernel.org>
   7
   8 commit a58f2cef26e1ca44182c8b22f4f4395e702a5795 upstream.
   9
  10 There was the below bug report from Wu Fangsuo.
  11
  12 On the CMA allocation path, isolate_migratepages_range() could isolate
  13 unevictable LRU pages and reclaim_clean_page_from_list() can try to
  14 reclaim them if they are clean file-backed pages.
  15
  16   page:ffffffbf02f33b40 count:86 mapcount:84 mapping:ffffffc08fa7a810 index:0x24
  17   flags: 0x19040c(referenced|uptodate|arch_1|mappedtodisk|unevictable|mlocked)
  18   raw: 000000000019040c ffffffc08fa7a810 0000000000000024 0000005600000053
  19   raw: ffffffc009b05b20 ffffffc009b05b20 0000000000000000 ffffffc09bf3ee80
  20   page dumped because: VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page))
  21   page->mem_cgroup:ffffffc09bf3ee80
  22   ------------[ cut here ]------------
  23   kernel BUG at /home/build/farmland/adroid9.0/kernel/linux/mm/vmscan.c:1350!
  24   Internal error: Oops - BUG: 0 [#1] PREEMPT SMP
  25   Modules linked in:
  26   CPU: 0 PID: 7125 Comm: syz-executor Tainted: G S              4.14.81 #3
  27   Hardware name: ASR AQUILAC EVB (DT)
  28   task: ffffffc00a54cd00 task.stack: ffffffc009b00000
  29   PC is at shrink_page_list+0x1998/0x3240
  30   LR is at shrink_page_list+0x1998/0x3240
  31   pc : [<ffffff90083a2158>] lr : [<ffffff90083a2158>] pstate: 60400045
  32   sp : ffffffc009b05940
  33   ..
  34      shrink_page_list+0x1998/0x3240
  35      reclaim_clean_pages_from_list+0x3c0/0x4f0
  36      alloc_contig_range+0x3bc/0x650
  37      cma_alloc+0x214/0x668
  38      ion_cma_allocate+0x98/0x1d8
  39      ion_alloc+0x200/0x7e0
  40      ion_ioctl+0x18c/0x378
  41      do_vfs_ioctl+0x17c/0x1780
  42      SyS_ioctl+0xac/0xc0
  43
  44 Wu found it's due to commit ad6b67041a45 ("mm: remove SWAP_MLOCK in
  45 ttu").  Before that, unevictable pages go to cull_mlocked so that we
  46 can't reach the VM_BUG_ON_PAGE line.
  47
  48 To fix the issue, this patch filters out unevictable LRU pages from the
  49 reclaim_clean_pages_from_list in CMA.
  50
  51 Link: http://lkml.kernel.org/r/20190524071114.74202-1-minchan@kernel.org
  52 Fixes: ad6b67041a45 ("mm: remove SWAP_MLOCK in ttu")
  53 Signed-off-by: Minchan Kim <minchan@kernel.org>
  54 Reported-by: Wu Fangsuo <fangsuowu@asrmicro.com>
  55 Debugged-by: Wu Fangsuo <fangsuowu@asrmicro.com>
  56 Tested-by: Wu Fangsuo <fangsuowu@asrmicro.com>
  57 Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
  58 Acked-by: Michal Hocko <mhocko@suse.com>
  59 Cc: Pankaj Suryawanshi <pankaj.suryawanshi@einfochips.com>
  60 Cc: <stable@vger.kernel.org>    [4.12+]
  61 Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
  62 Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
  63 Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
  64
  65 ---
  66  mm/vmscan.c |    2 +-
  67  1 file changed, 1 insertion(+), 1 deletion(-)
  68
  69 --- a/mm/vmscan.c
  70 +++ b/mm/vmscan.c
  71 @@ -1510,7 +1510,7 @@ unsigned long reclaim_clean_pages_from_l
  72
  73         list_for_each_entry_safe(page, next, page_list, lru) {
  74                 if (page_is_file_cache(page) && !PageDirty(page) &&
  75 -                   !__PageMovable(page)) {
  76 +                   !__PageMovable(page) && !PageUnevictable(page)) {
  77                         ClearPageActive(page);
  78                         list_move(&page->lru, &clean_pages);
  79                 }