linux-kernel - Re: lost connection to test machine (4)

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Date:   Mon, 12 Feb 2018 09:03:25 -0800
From:   Tejun Heo <tj@...nel.org>
To:     Daniel Borkmann <daniel@...earbox.net>
Cc:     dennisszhou@...il.com, Dmitry Vyukov <dvyukov@...gle.com>,
        syzbot <syzbot+adb03f3f0bb57ce3acda@...kaller.appspotmail.com>,
        Alexei Starovoitov <ast@...nel.org>,
        netdev <netdev@...r.kernel.org>,
        LKML <linux-kernel@...r.kernel.org>,
        syzkaller-bugs@...glegroups.com
Subject: Re: lost connection to test machine (4)

Hello, Daniel.

On Mon, Feb 12, 2018 at 06:00:13PM +0100, Daniel Borkmann wrote:
> [ +Dennis, +Tejun ]
> 
> Looks like we're stuck in percpu allocator with key/value size of 4 bytes
> each and large number of entries (max_entries) in the reproducer in above
> link.
> 
> Could we have some __GFP_NORETRY semantics and let allocations fail instead
> of triggering OOM killer?

For some part, maybe, but not generally.  The virt area allocation
goes down to page table allocation which is hard coded to use
GFP_KERNEL in arch mm code.

Thanks.

-- 
tejun