mm: fix madivse_pageout mishandling on non-LRU page

MADV_PAGEOUT tries to isolate non-LRU pages and gets a warning from
isolate_lru_page below.

Fix it by checking PageLRU in advance.

------------[ cut here ]------------
trying to isolate tail page
WARNING: CPU: 0 PID: 6175 at mm/folio-compat.c:158 isolate_lru_page+0x130/0x140
Modules linked in:
CPU: 0 PID: 6175 Comm: syz-executor.0 Not tainted 5.18.12 #1
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014
RIP: 0010:isolate_lru_page+0x130/0x140

Link: https://lore.kernel.org/linux-mm/485f8c33.2471b.182d5726afb.Coremail.hantianshuo@iie.ac.cn/
Link: https://lkml.kernel.org/r/20220908151204.762596-1-minchan@kernel.org
Fixes: 1a4e58cce84e ("mm: introduce MADV_PAGEOUT")
Signed-off-by: Minchan Kim <minchan@kernel.org>
Reported-by: 韩天ç`\95 <hantianshuo@iie.ac.cn>
Suggested-by: Yang Shi <shy828301@gmail.com>
Acked-by: Yang Shi <shy828301@gmail.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/madvise.c b/mm/madvise.c
index 5f0f0948a50e4399a3115f6cd12ae8deae25f1bd..9ff51650f4f072f42fade3dc20090faf15c2a7f2 100644 (file)
--- a/mm/madvise.c
+++ b/mm/madvise.c
@@ -451,8 +451,11 @@ regular_page:
                        continue;
                }
 
-               /* Do not interfere with other mappings of this page */
-               if (page_mapcount(page) != 1)
+               /*
+                * Do not interfere with other mappings of this page and
+                * non-LRU page.
+                */
+               if (!PageLRU(page) || page_mapcount(page) != 1)
                        continue;
 
                VM_BUG_ON_PAGE(PageTransCompound(page), page);