On 7/21/20 5:11 AM, Kirill A. Shutemov wrote: > On Mon, Jul 20, 2020 at 04:51:44PM -0700, Andrew Morton wrote: >> On Sun, 19 Jul 2020 14:10:19 -0700 syzbot <syzbot+c48f34012b06c4ac67dd@xxxxxxxxxxxxxxxxxxxxxxxxx> wrote: >> >>> syzbot has found a reproducer for the following issue on: >>> >>> HEAD commit: 4c43049f Add linux-next specific files for 20200716 >>> git tree: linux-next >>> console output: https://syzkaller.appspot.com/x/log.txt?x=12c56087100000 >>> kernel config: https://syzkaller.appspot.com/x/.config?x=2c76d72659687242 >>> dashboard link: https://syzkaller.appspot.com/bug?extid=c48f34012b06c4ac67dd >>> compiler: gcc (GCC) 10.1.0-syz 20200507 >>> syz repro: https://syzkaller.appspot.com/x/repro.syz?x=1344abeb100000 >>> >>> IMPORTANT: if you fix the issue, please add the following tag to the commit: >>> Reported-by: syzbot+c48f34012b06c4ac67dd@xxxxxxxxxxxxxxxxxxxxxxxxx >> >> Thanks. >> >> __handle_mm_fault >> ->pmd_migration_entry_wait >> ->migration_entry_to_page >> >> stumbled onto an unlocked page. >> >> I don't immediately see a cause. Perhaps Matthew's "THP prep patches", >> perhaps something else. >> >> Is it possible to perform a bisection? > > Maybe it's related to the new lock_page_async()? Shouldn't be used for any of those paths at all, though of course can't rule out a bug that triggers it somehow. A bisection would be nice. -- Jens Axboe
