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 <20200715160426.225feefb@canb.auug.org.au>
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From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Fri, 30 Oct 2020 10:53:44 +0100
Message-ID: <CACT4Y+a6Z-8Vp4Z_0cqbckiCedQSGD=hp7n4o-CJzp8LKdMSNQ@mail.gmail.com>
Subject: Re: kernel panic: System is deadlocked on memory
To:     Stephen Rothwell <sfr@canb.auug.org.au>
Cc:     Yafang Shao <laoar.shao@gmail.com>,
        syzbot <syzbot+98be80110b9043885626@syzkaller.appspotmail.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        LKML <linux-kernel@vger.kernel.org>,
        Linux MM <linux-mm@kvack.org>,
        syzkaller-bugs <syzkaller-bugs@googlegroups.com>
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On Wed, Jul 15, 2020 at 8:04 AM Stephen Rothwell <sfr@canb.auug.org.au> wrote:
>
> Hi all,
>
> On Wed, 15 Jul 2020 13:54:04 +0800 Yafang Shao <laoar.shao@gmail.com> wrote:
> >
> > On Wed, Jul 15, 2020 at 12:49 PM syzbot
> > <syzbot+98be80110b9043885626@syzkaller.appspotmail.com> wrote:
> > >
> > > Hello,
> > >
> > > syzbot found the following issue on:
> > >
> > > HEAD commit:    d31958b3 Add linux-next specific files for 20200710
> > > git tree:       linux-next
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=11a2fe13100000
> > > kernel config:  https://syzkaller.appspot.com/x/.config?x=3fe4fccb94cbc1a6
> > > dashboard link: https://syzkaller.appspot.com/bug?extid=98be80110b9043885626
> > > compiler:       gcc (GCC) 10.1.0-syz 20200507
> > > syz repro:      https://syzkaller.appspot.com/x/repro.syz?x=101ec967100000
> > > C reproducer:   https://syzkaller.appspot.com/x/repro.c?x=14a77000900000
> > >
> > > The issue was bisected to:
> > >
> > > commit e642d9be463d02c735cd99a9a904063324ee03d6
> > > Author: Yafang Shao <laoar.shao@gmail.com>
> > > Date:   Fri Jul 10 04:58:08 2020 +0000
> > >
> > >     mm, oom: make the calculation of oom badness more accurate
> > >
> > > bisection log:  https://syzkaller.appspot.com/x/bisect.txt?x=1432bd77100000
> > > final oops:     https://syzkaller.appspot.com/x/report.txt?x=1632bd77100000
> > > console output: https://syzkaller.appspot.com/x/log.txt?x=1232bd77100000
> > >
> > > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > > Reported-by: syzbot+98be80110b9043885626@syzkaller.appspotmail.com
> > > Fixes: e642d9be463d ("mm, oom: make the calculation of oom badness more accurate")
> > >
> > > Out of memory and no killable processes...
> > > Kernel panic - not syncing: System is deadlocked on memory
> > > CPU: 0 PID: 6810 Comm: syz-executor919 Not tainted 5.8.0-rc4-next-20200710-syzkaller #0
> > > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > > Call Trace:
> > >  __dump_stack lib/dump_stack.c:77 [inline]
> > >  dump_stack+0x18f/0x20d lib/dump_stack.c:118
> > >  panic+0x2e3/0x75c kernel/panic.c:231
> > >  out_of_memory mm/oom_kill.c:1106 [inline]
> > >  out_of_memory.cold+0xa6/0x182 mm/oom_kill.c:1041
> > >  pagefault_out_of_memory+0x109/0x11c mm/oom_kill.c:1135
> > >  mm_fault_error+0x123/0x380 arch/x86/mm/fault.c:930
> > >  do_user_addr_fault+0x5f8/0xbf0 arch/x86/mm/fault.c:1317
> > >  handle_page_fault arch/x86/mm/fault.c:1351 [inline]
> > >  exc_page_fault+0xab/0x170 arch/x86/mm/fault.c:1404
> > >  asm_exc_page_fault+0x1e/0x30 arch/x86/include/asm/idtentry.h:544
> > > RIP: 0033:0x40154d
> > > Code: Bad RIP value.
> > > RSP: 002b:00007ffddf4649b0 EFLAGS: 00010202
> > > RAX: 0000000000000001 RBX: 0000000000000000 RCX: fffffffffffffffd
> > > RDX: 0000000000000001 RSI: 00007ffddf4665e0 RDI: ffffffffffffffff
> > > RBP: 00007ffddf4665e0 R08: 0000000000000000 R09: 0000000000000001
> > > R10: 0000000000000064 R11: 0000000000000246 R12: ffffffffffffffff
> > > R13: 0000000000000003 R14: 0000000000000000 R15: 0000000000000000
> > > Kernel Offset: disabled
> > > Rebooting in 86400 seconds..
> > >
> > >
> > > ---
> > > This report is generated by a bot. It may contain errors.
> > > See https://goo.gl/tpsmEJ for more information about syzbot.
> > > syzbot engineers can be reached at syzkaller@googlegroups.com.
> > >
> > > syzbot will keep track of this issue. See:
> > > https://goo.gl/tpsmEJ#status for how to communicate with syzbot.
> > > For information about bisection process see: https://goo.gl/tpsmEJ#bisection
> > > syzbot can test patches for this issue, for details see:
> > > https://goo.gl/tpsmEJ#testing-patches
> >
> > Thanks for the report.
> > This issue has been already fixed by
> > "mm-oom-make-the-calculation-of-oom-badness-more-accurate-v3", which
> > is already in the -next tree.
>
> #syz fix: mm-oom-make-the-calculation-of-oom-badness-more-accurate-v3

The final patch title is:

#syz fix: mm, oom: make the calculation of oom badness more accurate


> --
> Cheers,
> Stephen Rothwell