diff options
authorMinchan Kim <>2019-06-13 15:56:15 -0700
committerLinus Torvalds <>2019-06-13 17:34:56 -1000
commita58f2cef26e1ca44182c8b22f4f4395e702a5795 (patch)
parent59ea6d06cfa9247b586a695c21f94afa7183af74 (diff)
mm/vmscan.c: fix trying to reclaim unevictable LRU page
There was the below bug report from Wu Fangsuo. On the CMA allocation path, isolate_migratepages_range() could isolate unevictable LRU pages and reclaim_clean_page_from_list() can try to reclaim them if they are clean file-backed pages. page:ffffffbf02f33b40 count:86 mapcount:84 mapping:ffffffc08fa7a810 index:0x24 flags: 0x19040c(referenced|uptodate|arch_1|mappedtodisk|unevictable|mlocked) raw: 000000000019040c ffffffc08fa7a810 0000000000000024 0000005600000053 raw: ffffffc009b05b20 ffffffc009b05b20 0000000000000000 ffffffc09bf3ee80 page dumped because: VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page)) page->mem_cgroup:ffffffc09bf3ee80 ------------[ cut here ]------------ kernel BUG at /home/build/farmland/adroid9.0/kernel/linux/mm/vmscan.c:1350! Internal error: Oops - BUG: 0 [#1] PREEMPT SMP Modules linked in: CPU: 0 PID: 7125 Comm: syz-executor Tainted: G S 4.14.81 #3 Hardware name: ASR AQUILAC EVB (DT) task: ffffffc00a54cd00 task.stack: ffffffc009b00000 PC is at shrink_page_list+0x1998/0x3240 LR is at shrink_page_list+0x1998/0x3240 pc : [<ffffff90083a2158>] lr : [<ffffff90083a2158>] pstate: 60400045 sp : ffffffc009b05940 .. shrink_page_list+0x1998/0x3240 reclaim_clean_pages_from_list+0x3c0/0x4f0 alloc_contig_range+0x3bc/0x650 cma_alloc+0x214/0x668 ion_cma_allocate+0x98/0x1d8 ion_alloc+0x200/0x7e0 ion_ioctl+0x18c/0x378 do_vfs_ioctl+0x17c/0x1780 SyS_ioctl+0xac/0xc0 Wu found it's due to commit ad6b67041a45 ("mm: remove SWAP_MLOCK in ttu"). Before that, unevictable pages go to cull_mlocked so that we can't reach the VM_BUG_ON_PAGE line. To fix the issue, this patch filters out unevictable LRU pages from the reclaim_clean_pages_from_list in CMA. Link: Fixes: ad6b67041a45 ("mm: remove SWAP_MLOCK in ttu") Signed-off-by: Minchan Kim <> Reported-by: Wu Fangsuo <> Debugged-by: Wu Fangsuo <> Tested-by: Wu Fangsuo <> Reviewed-by: Andrew Morton <> Acked-by: Michal Hocko <> Cc: Pankaj Suryawanshi <> Cc: <> [4.12+] Signed-off-by: Andrew Morton <> Signed-off-by: Linus Torvalds <>
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c
index ffa82b1d39a2..7889f583ced9 100644
--- a/mm/vmscan.c
+++ b/mm/vmscan.c
@@ -1505,7 +1505,7 @@ unsigned long reclaim_clean_pages_from_list(struct zone *zone,
list_for_each_entry_safe(page, next, page_list, lru) {
if (page_is_file_cache(page) && !PageDirty(page) &&
- !__PageMovable(page)) {
+ !__PageMovable(page) && !PageUnevictable(page)) {
list_move(&page->lru, &clean_pages);