From: Greg KH <greg@kroah.com>
To: Christian Eggers <ceggers@arri.de>
Cc: stable@vger.kernel.org, Willem de Bruijn <willemb@google.com>,
Deepa Dinamani <deepa.kernel@gmail.com>
Subject: Re: [PATCH] socket: don't clear SOCK_TSTAMP_NEW when SO_TIMESTAMPNS is disabled
Date: Thu, 29 Oct 2020 12:04:14 +0100 [thread overview]
Message-ID: <20201029110414.GD3840801@kroah.com> (raw)
In-Reply-To: <20201027171526.23151-1-ceggers@arri.de>
On Tue, Oct 27, 2020 at 06:15:26PM +0100, Christian Eggers wrote:
> [ Upstream commit 4e3bbb33e6f36e4b05be1b1b9b02e3dd5aaa3e69 ]
>
> SOCK_TSTAMP_NEW (timespec64 instead of timespec) is also used for
> hardware time stamps (configured via SO_TIMESTAMPING_NEW).
>
> User space (ptp4l) first configures hardware time stamping via
> SO_TIMESTAMPING_NEW which sets SOCK_TSTAMP_NEW. In the next step, ptp4l
> disables SO_TIMESTAMPNS(_NEW) (software time stamps), but this must not
> switch hardware time stamps back to "32 bit mode".
>
> This problem happens on 32 bit platforms were the libc has already
> switched to struct timespec64 (from SO_TIMExxx_OLD to SO_TIMExxx_NEW
> socket options). ptp4l complains with "missing timestamp on transmitted
> peer delay request" because the wrong format is received (and
> discarded).
>
> Fixes: 887feae36aee ("socket: Add SO_TIMESTAMP[NS]_NEW")
> Signed-off-by: Christian Eggers <ceggers@arri.de>
> Acked-by: Willem de Bruijn <willemb@google.com>
> Acked-by: Deepa Dinamani <deepa.kernel@gmail.com>
> ---
> Hi Greg,
>
> I just got your E-mail(s) that this patch has been applied to 5.8 and 5.9.
> This is a back port for the same problem on 5.4. It does the same as the
> upstream patch, only the affected code is at another position here. Please
> decide yourself whether the Acked-by: tags (from the upstream patch) should
> be kept or removed.
>
> This back port is only required for 5.4, older kernels like 4.19 are not
> affected.
>
> regards
> Christian
Now queued up, thanks.
greg k-h
next prev parent reply other threads:[~2020-10-29 11:03 UTC|newest]
Thread overview: 3+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-10-27 17:15 [PATCH] socket: don't clear SOCK_TSTAMP_NEW when SO_TIMESTAMPNS is disabled Christian Eggers
2020-10-29 11:04 ` Greg KH [this message]
2020-10-29 11:07 ` Christian Eggers
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