Re: [PATCH 4.4 093/132] sock: Reset dst when changing sk_mark via setsockopt

[Greg Kroah-Hartman]

On Wed, Nov 27, 2019 at 09:31:24PM +0100, Greg Kroah-Hartman wrote:
> From: David Barmann <david.barmann@xxxxxxxxxxxxx>
> 
> [ Upstream commit 50254256f382c56bde87d970f3d0d02fdb76ec70 ]
> 
> When setting the SO_MARK socket option, if the mark changes, the dst
> needs to be reset so that a new route lookup is performed.
> 
> This fixes the case where an application wants to change routing by
> setting a new sk_mark.  If this is done after some packets have already
> been sent, the dst is cached and has no effect.
> 
> Signed-off-by: David Barmann <david.barmann@xxxxxxxxxxxxx>
> Reviewed-by: Eric Dumazet <edumazet@xxxxxxxxxx>
> Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
> Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
> ---
>  net/core/sock.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)

This patch breaks a bunch of runtime tests in the Android ecosystem,
that somehow all successfully run just fine with kernels newer than 5.0
where this patch showed up in, so I think this is an "incomplete
backport".

Because of this, I'm going to drop this from the stable trees now.

thanks,

greg k-h