On Mon 10-06-19 20:21:12, Minchan Kim wrote: [...] > >From 5cb8958ea240e2580bd2b331448009e8e1854240 Mon Sep 17 00:00:00 2001 > From: Minchan Kim <minc...@kernel.org> > Date: Fri, 24 May 2019 15:54:10 +0900 > Subject: [PATCH] mm: fix trying to reclaim unevicable LRU page > > There was below bugreport from Wu Fangsuo. > > In 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. > > 7200 [ 680.491097] c4 7125 (syz-executor) page:ffffffbf02f33b40 count:86 > mapcount:84 mapping:ffffffc08fa7a810 index:0x24 > 7201 [ 680.531186] c4 7125 (syz-executor) flags: > 0x19040c(referenced|uptodate|arch_1|mappedtodisk|unevictable|mlocked) > 7202 [ 680.544987] c0 7125 (syz-executor) raw: 000000000019040c > ffffffc08fa7a810 0000000000000024 0000005600000053 > 7203 [ 680.556162] c0 7125 (syz-executor) raw: ffffffc009b05b20 > ffffffc009b05b20 0000000000000000 ffffffc09bf3ee80 > 7204 [ 680.566860] c0 7125 (syz-executor) page dumped because: > VM_BUG_ON_PAGE(PageLRU(page) || PageUnevictable(page)) > 7205 [ 680.578038] c0 7125 (syz-executor) page->mem_cgroup:ffffffc09bf3ee80 > 7206 [ 680.585467] c0 7125 (syz-executor) ------------[ cut here > ]------------ > 7207 [ 680.592466] c0 7125 (syz-executor) kernel BUG at > /home/build/farmland/adroid9.0/kernel/linux/mm/vmscan.c:1350! > 7223 [ 680.603663] c0 7125 (syz-executor) Internal error: Oops - BUG: 0 [#1] > PREEMPT SMP > 7224 [ 680.611436] c0 7125 (syz-executor) Modules linked in: > 7225 [ 680.616769] c0 7125 (syz-executor) CPU: 0 PID: 7125 Comm: > syz-executor Tainted: G S 4.14.81 #3 > 7226 [ 680.626826] c0 7125 (syz-executor) Hardware name: ASR AQUILAC EVB (DT) > 7227 [ 680.633623] c0 7125 (syz-executor) task: ffffffc00a54cd00 task.stack: > ffffffc009b00000 > 7228 [ 680.641917] c0 7125 (syz-executor) PC is at > shrink_page_list+0x1998/0x3240 > 7229 [ 680.649144] c0 7125 (syz-executor) LR is at > shrink_page_list+0x1998/0x3240 > 7230 [ 680.656303] c0 7125 (syz-executor) pc : [<ffffff90083a2158>] lr : > [<ffffff90083a2158>] pstate: 60400045 > 7231 [ 680.666086] c0 7125 (syz-executor) sp : ffffffc009b05940 > .. > 7342 [ 681.671308] c0 7125 (syz-executor) [<ffffff90083a2158>] > shrink_page_list+0x1998/0x3240 > 7343 [ 681.679567] c0 7125 (syz-executor) [<ffffff90083a3dc0>] > reclaim_clean_pages_from_list+0x3c0/0x4f0 > 7344 [ 681.688793] c0 7125 (syz-executor) [<ffffff900837ed64>] > alloc_contig_range+0x3bc/0x650 > 7347 [ 681.717421] c0 7125 (syz-executor) [<ffffff90084925cc>] > cma_alloc+0x214/0x668 > 7348 [ 681.724892] c0 7125 (syz-executor) [<ffffff90091e4d78>] > ion_cma_allocate+0x98/0x1d8 > 7349 [ 681.732872] c0 7125 (syz-executor) [<ffffff90091e0b20>] > ion_alloc+0x200/0x7e0 > 7350 [ 681.740302] c0 7125 (syz-executor) [<ffffff90091e154c>] > ion_ioctl+0x18c/0x378 > 7351 [ 681.747738] c0 7125 (syz-executor) [<ffffff90084c6824>] > do_vfs_ioctl+0x17c/0x1780 > 7352 [ 681.755514] c0 7125 (syz-executor) [<ffffff90084c7ed4>] > SyS_ioctl+0xac/0xc0 > > Wu found it's due to [1]. Before that, unevictable page goes to cull_mlocked > routine so that it couldn't reach the VM_BUG_ON_PAGE line. > > To fix the issue, this patch filter out unevictable LRU pages > from the reclaim_clean_pages_from_list in CMA. > > [1] ad6b67041a45, mm: remove SWAP_MLOCK in ttu > > Cc: <sta...@kernel.org> [4.12+] > Reported-debugged-by: Wu Fangsuo <fangsu...@asrmicro.com> > Signed-off-by: Minchan Kim <minc...@kernel.org>
OK, this looks better. Thanks! Acked-by: Michal Hocko <mho...@suse.com> > --- > mm/vmscan.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/mm/vmscan.c b/mm/vmscan.c > index d9c3e873eca6..7350afae5c3c 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)) { > ClearPageActive(page); > list_move(&page->lru, &clean_pages); > } > -- > 2.22.0.rc2.383.gf4fbbf30c2-goog > -- Michal Hocko SUSE Labs