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From:   "H. Nikolaus Schaller" <hns@goldelico.com>
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Subject: MIPS: bug: gettimeofday syscall broken on CI20 board?
Date:   Thu, 7 Nov 2019 17:21:13 +0100
Message-Id: <18788C50-F29B-4BD7-89F6-B056FF490214@goldelico.com>
Cc:     Ralf Baechle <ralf@linux-mips.org>,
        Paul Burton <paul.burton@mips.com>,
        MIPS Creator CI20 Development 
        <mips-creator-ci20-dev@googlegroups.com>,
        Discussions about the Letux Kernel 
        <letux-kernel@openphoenux.org>, linux-mips@vger.kernel.org,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
To:     Vincenzo Frascino <vincenzo.frascino@arm.com>
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Sender: linux-kernel-owner@vger.kernel.org
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Hi,
I am trying to run v5.4-rc6 on the CI20 board (jz4780) and it
is almost ok. Except one strange thing.

If I install a v4.19.81 kernel I can initialize the
ethernet interface and dhclient works.

If I install a v5.4-rc6 kernel on exactly the same
rootfs dhclient fails with

root@letux:~# dhclient
../../../../lib/isc/unix/time.c:200: Operation not permitted
root@letux:~#

I have done some strace and the first significant difference
is that with v5.4-rc6 there is no gettimeofday syscall.

Another symptom pointing in the same direction is that
after manually assigning an IP address I can run ping
but get strange time values.

So it may be that

24640f233b46 mips: Add support for generic vDSO

did break gettimeofday when used with latest Debian Stretch
libraries. I tried to git revert but there are conflicts.

Just a side-note: both kernels work with Debian Jessie,
which likely has an older gettimeofday wrapper that
is not influenced by some subtle change.

BR and thanks,
Nikolaus Schaller