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From:   Dmitry Vyukov <dvyukov@google.com>
Date:   Wed, 28 Jul 2021 10:37:44 +0200
Message-ID: <CACT4Y+apS=TXOSNkTaVXxARNDmOZ_R-ntvV8t-tXMk1ggGGspg@mail.gmail.com>
Subject: Re: [syzbot] BUG: sleeping function called from invalid context in munlock_vma_pages_range
To:     syzbot <syzbot+2e3ee45ea14cd0b81f26@syzkaller.appspotmail.com>,
        linux-kernel@vger.kernel.org, syzkaller-bugs@googlegroups.com
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On Thu, 15 Jul 2021 at 23:25, 'Hugh Dickins' via syzkaller-bugs
<syzkaller-bugs@googlegroups.com> wrote:
>
> On Thu, 15 Jul 2021, syzbot wrote:
>
> > Hello,
> >
> > syzbot found the following issue on:
> >
> > HEAD commit:    98f7fdced2e0 Merge tag 'irq-urgent-2021-07-11' of git://gi..
> > git tree:       upstream
> > console output: https://syzkaller.appspot.com/x/log.txt?x=13576e9c300000
> > kernel config:  https://syzkaller.appspot.com/x/.config?x=da2203b984f4af9f
> > dashboard link: https://syzkaller.appspot.com/bug?extid=2e3ee45ea14cd0b81f26
> > compiler:       Debian clang version 11.0.1-2
> >
> > Unfortunately, I don't have any reproducer for this issue yet.
> >
> > IMPORTANT: if you fix the issue, please add the following tag to the commit:
> > Reported-by: syzbot+2e3ee45ea14cd0b81f26@syzkaller.appspotmail.com
> >
> > BUG: sleeping function called from invalid context at mm/mlock.c:482
>
> Fixed by
> 023e1a8dd502 ("mm/rmap: fix new bug: premature return from page_mlock_one()")
> which went into the tree soon after the HEAD shown above
> (but was posted before any syzbot report, so contained no syzbot tag).

#syz fix: mm/rmap: fix new bug: premature return from page_mlock_one()


> > in_atomic(): 1, irqs_disabled(): 0, non_block: 0, pid: 14373, name: syz-executor.5
> > INFO: lockdep is turned off.
> > Preemption disabled at:
> > [<0000000000000000>] 0x0
> > CPU: 1 PID: 14373 Comm: syz-executor.5 Tainted: G        W         5.13.0-syzkaller #0
> > Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
> > Call Trace:
> >  __dump_stack lib/dump_stack.c:88 [inline]
> >  dump_stack_lvl+0x1d3/0x29f lib/dump_stack.c:105
> >  ___might_sleep+0x4e5/0x6b0 kernel/sched/core.c:9154
> >  munlock_vma_pages_range+0xa80/0xf60 mm/mlock.c:482
> >  mlock_fixup+0x40f/0x580 mm/mlock.c:552
> >  apply_mlockall_flags mm/mlock.c:768 [inline]
> >  __do_sys_munlockall+0x1ef/0x310 mm/mlock.c:810
> >  do_syscall_x64 arch/x86/entry/common.c:50 [inline]
> >  do_syscall_64+0x3d/0xb0 arch/x86/entry/common.c:80
> >  entry_SYSCALL_64_after_hwframe+0x44/0xae
> > RIP: 0033:0x4665d9
> > Code: ff ff c3 66 2e 0f 1f 84 00 00 00 00 00 0f 1f 40 00 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 73 01 c3 48 c7 c1 bc ff ff ff f7 d8 64 89 01 48
> > RSP: 002b:00007f448bc37188 EFLAGS: 00000246 ORIG_RAX: 0000000000000098
> > RAX: ffffffffffffffda RBX: 000000000056bf80 RCX: 00000000004665d9
> > RDX: 0000000000000000 RSI: 0000000000000000 RDI: 0000000000000000
> > RBP: 00000000004bfcb9 R08: 0000000000000000 R09: 0000000000000000
> > R10: 0000000000000000 R11: 0000000000000246 R12: 000000000056bf80
> > R13: 00007ffe7eb2d2ef R14: 00007f448bc37300 R15: 0000000000022000
> >
> >
> > ---
> > 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.
>
> --
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