On Tue, Aug 6, 2019 at 10:29 AM Michal Hocko <mhocko@xxxxxxxxxx> wrote: > > On Sat 03-08-19 05:06:43, Minchan Kim wrote: > > On Fri, Aug 02, 2019 at 10:58:05AM -0700, syzbot wrote: > > > Hello, > > > > > > syzbot found the following crash on: > > > > > > HEAD commit: 0d8b3265 Add linux-next specific files for 20190729 > > > git tree: linux-next > > > console output: https://syzkaller.appspot.com/x/log.txt?x=1663c7d0600000 > > > kernel config: https://syzkaller.appspot.com/x/.config?x=ae96f3b8a7e885f7 > > > dashboard link: https://syzkaller.appspot.com/bug?extid=8e6326965378936537c3 > > > compiler: gcc (GCC) 9.0.0 20181231 (experimental) > > > syz repro: https://syzkaller.appspot.com/x/repro.syz?x=133c437c600000 > > > C reproducer: https://syzkaller.appspot.com/x/repro.c?x=15645854600000 > > > > > > The bug was bisected to: > > > > > > commit 06a833a1167e9cbb43a9a4317ec24585c6ec85cb > > > Author: Minchan Kim <minchan@xxxxxxxxxx> > > > Date: Sat Jul 27 05:12:38 2019 +0000 > > > > > > mm: introduce MADV_PAGEOUT > > > > > > bisection log: https://syzkaller.appspot.com/x/bisect.txt?x=1545f764600000 > > > final crash: https://syzkaller.appspot.com/x/report.txt?x=1745f764600000 > > > console output: https://syzkaller.appspot.com/x/log.txt?x=1345f764600000 > > > > > > IMPORTANT: if you fix the bug, please add the following tag to the commit: > > > Reported-by: syzbot+8e6326965378936537c3@xxxxxxxxxxxxxxxxxxxxxxxxx > > > Fixes: 06a833a1167e ("mm: introduce MADV_PAGEOUT") > > > > > > raw: 01fffc0000090025 dead000000000100 dead000000000122 ffff88809c49f741 > > > raw: 0000000000020000 0000000000000000 00000002ffffffff ffff88821b6eaac0 > > > page dumped because: VM_BUG_ON_PAGE(PageActive(page)) > > > page->mem_cgroup:ffff88821b6eaac0 > > > ------------[ cut here ]------------ > > > kernel BUG at mm/vmscan.c:1156! > > > invalid opcode: 0000 [#1] PREEMPT SMP KASAN > > > CPU: 1 PID: 9846 Comm: syz-executor110 Not tainted 5.3.0-rc2-next-20190729 > > > #54 > > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS > > > Google 01/01/2011 > > > RIP: 0010:shrink_page_list+0x2872/0x5430 mm/vmscan.c:1156 > > > > My old version had PG_active flag clear but it seems to lose it with revising > > patchsets. Thanks, Sizbot! > > > > >From 66d64988619ef7e86b0002b2fc20fdf5b84ad49c Mon Sep 17 00:00:00 2001 > > From: Minchan Kim <minchan@xxxxxxxxxx> > > Date: Sat, 3 Aug 2019 04:54:02 +0900 > > Subject: [PATCH] mm: Clear PG_active on MADV_PAGEOUT > > > > shrink_page_list expects every pages as argument should be no active > > LRU pages so we need to clear PG_active. > > Ups, missed that during review. > > > > > Reported-by: syzbot+8e6326965378936537c3@xxxxxxxxxxxxxxxxxxxxxxxxx > > Fixes: 06a833a1167e ("mm: introduce MADV_PAGEOUT") > > This is not a valid sha1 because it likely comes from linux-next. I > guess Andrew will squash it into mm-introduce-madv_pageout.patch > > Just for the record > Acked-by: Michal Hocko <mhocko@xxxxxxxx> > > And thanks for syzkaller to exercise the new interface so quickly! syzkaller don't have any new descriptions for MADV_PAGEOUT. It's just the power of rand. If there is something more complex than just a single flag, then it may benefit from explicit interface descriptions. > > Signed-off-by: Minchan Kim <minchan@xxxxxxxxxx> > > --- > > mm/vmscan.c | 1 + > > 1 file changed, 1 insertion(+) > > > > diff --git a/mm/vmscan.c b/mm/vmscan.c > > index 47aa2158cfac2..e2a8d3f5bbe48 100644 > > --- a/mm/vmscan.c > > +++ b/mm/vmscan.c > > @@ -2181,6 +2181,7 @@ unsigned long reclaim_pages(struct list_head *page_list) > > } > > > > if (nid == page_to_nid(page)) { > > + ClearPageActive(page); > > list_move(&page->lru, &node_page_list); > > continue; > > } > > -- > > 2.22.0.770.g0f2c4a37fd-goog > > -- > Michal Hocko > SUSE Labs > > -- > You received this message because you are subscribed to the Google Groups "syzkaller-bugs" group. > To unsubscribe from this group and stop receiving emails from it, send an email to syzkaller-bugs+unsubscribe@xxxxxxxxxxxxxxxx. > To view this discussion on the web visit https://groups.google.com/d/msgid/syzkaller-bugs/20190806082907.GI11812%40dhcp22.suse.cz.
